Saturday, February 13, 2016

Paleontological Research Tips, part 3: a complete idiot's guide to taking photographs that don't suck

Here's the third installment of my series on paleontological research tips! This one is on specimen photography. It took me years to learn all this crap, picking up tips here and there from various sources, but the sheer majority of this was learned from my Ph.D. adviser R. Ewan Fordyce who is an unusually talented and skilled photographer. Ewan passes down much of his knowledge to his students, and we try to pick up as much of it as possible. Some paleontologists don't worry enough about taking and publishing good photographs, whereas others worry too much - photography can seem daunting, but it's OK - we're all here to repent and better ourselves through learning.

A very valuable skill to have as a paleontologist - and many scientists in general - is the ability to take high quality photographs that are acceptable for publication. Evidently, judging from the figures of many published papers I've read, I see that there is quite a lot of room for improvement. As per usual I won't name any names, and rather than pretend that I was born perfect and have not learned anything, I'll go ahead and make fun of some of my earlier published figures before I learned what I know about photography now. So, before I go into the nitty gritty, let's look at a couple of figures with several photographs each and critique what we can see.


Here's a shining example of a published figure I'm not very proud of - Boessenecker 2013: J. Paleo.

The two examples here are a figure I'm not so proud of, and another which I find to be one of my most visually satisfying figures. The first figure is from my J. Paleo paper on barnacle encrusted sea lion bones from Oregon, one of my first post-master's degree manuscripts which had a bit of a tortured review history, and I had taken all of the photos in fall of 2011. I started attempting (notice the word choice!) to publish the paper in summer 2012 when I was in NZ (northern, not austral summer) - which meant that I could not re-take the photos. I was beginning to learn at that point, and new that the photos weren't great, but had no idea when I'd be able to go back to UCMP at Berkeley where the fossils were. Even the reviewers complained about the photos. The lighting and contrast is a bit different, with the dorsal views having much higher contrast and being somewhat sharper; part 4 is washed out and mostly out of focus, and the same can be argued for part 3; parts 1 and 2 look fine. In part 5, the transverse processes are out of focus; part 6 is almost entirely in focus, but washed out. These photos were shot hand-held under direct sunlight, hence the 1) fine scale fuzziness and 2) extreme contrast.

And a figure with much, much better lighting, contrast, focus, and detail: the holotype periotic of Tohoraata raekohao. From Boessenecker and Fordyce 2015: Papers in Palaeontology.

The next figure is one I'm much more proud of - the periotic (inner ear bone) of the eomysticetid Tohoraata raekohao, derived from the first chapter of my Ph.D. thesis at University of Otago. This is not the published figure, but rather the super-dense and overly chaotic figure at the time of initial submission. Ignoring the anatomical labels written in the manner of a crazy person's living room wall manifesto, the photos are quite nice. All of them are consistent in lighting, contrast, lighting direction, and clarity. Everything is in focus - which is a bit of an impossibility for some lenses, but there is an advanced method to take care of that which I'll discuss below (see Advanced tips: focus stacking). In general, I can't point out anything glaringly obvious that's bad with this one, and am overall quite pleased. I did, after all, have to get my Ph.D. adviser R. Ewan Fordyce - well known in the field for painstakingly taking incredibly good photographs - to give me the OK to publish these images. These images were shot with 1) ammonium chloride coating, 2) focus-stacking for continuous focus, 3) soft lighting, 4) under manual setting with correct exposure set, and 5) on a camera stand.


My personal photography kit: yes, I bring all this crap with me to every museum visit. It's a pain, but it permits me maximum flexibility. Large camera tripod, medium tripod for LED lamp, tiny tripod, LED lamp, manual shutter release, camera body, short zoom, telephoto zoom lens, and of course a scale bar!


An example of my basic setup: camera tripod, fossil/scale bar on a white background, and the LED lamp positioned at upper left of photo.

Basic tips 1: the camera

I'll get this out of the way at the start: sure, you might be capable of taking decent photographs with a point and shoot or a smartphone, but for the purposes of this post I'm going to be talking about real cameras that have all sorts of scary knobs and dials with numbers on them. I'm talking about DSLR cameras - digital single lens reflex camera. I've met many people who buy these cameras, which often cost 400-500 us$ at the cheapest, and leave the camera setting on auto (the green box on the dial), and taking hundreds of crap photos for every good photo - wondering why they spent so damn much on the camera. You can treat an expensive DSLR like an overpriced point and shoot camera, but it's a bit like buying an armored humvee with a machine gun port on the roof to go grocery shopping and drop the girls off at soccer practice. So, if you want to take pictures with a smartphone or a crappy point and shoot, be my guest - but you won't be able to use many of the tips below, so go away.

Actually, that's not entirely true: smartphones and point and shoot cameras do have their uses, and owing to their smaller pricetag, are ideally suited towards field photography. Landscape photos out in nature (under regular daytime lighting) are easy to take and smartphones give you the option of panoramic panning photos. Because field photos are relatively easy, we're basically going to ignore them and mostly discuss close-up photographs of specimens.

DSLRs are pricey, but essentially anything where you can use a manual setting and change ISO, aperture (aka F-stop), and shutter speed is desirable. On smartphones/point and shoots only automatic settings are generally possible and the camera does it automatically for you. The camera is dumb; don't let it make decisions for you. I've got a relatively basic Canon Rebel EOS, but have used Nikon D1200, D700, and a D90 during my Ph.D. 

Basic tips 2: the lens

I'll admit I'm not that much of an expert on lenses, so this will be brief. Most cameras come with a standard 55-85 mm zoom lens; I've got a decent lens that came with an old film camera that took a swim in Monterey bay during fieldwork, which killed the camera but not the lens - and the lens is still happily clicking away on my current DSLR. Zoom lenses are great: the width of the photo can be modified, as can focus, but generally speaking the image quality is somewhat lower than a fixed focal length AKA prime lens. Prime lenses produce higher quality images, have a wider aperture (more on this below), and are generally lighter in weight as they have fewer internal lenses and working parts. The rub is that the focal length is fixed, meaning that if you are standing X feet away and cannot fit everything into frame, you cannot simply zoom out and either need to back away from the subject or swap with a different lens.

With prime lenses, the lower the number the shorter the lens and the wider the field of view; a standard prime lens is 50 mm, whereas a telephoto is 135mm, and a wide or extra wide angle lens is 34-14 mm (respectively). The shorter the prime lens, the greater the distortion (wide angle and extra wide approach a fish-eye lens), whereas minimal distortion is present in standard, telephoto, or super telephoto lenses. Here's the other rub: prime lenses are expensive, and if taking photos of a sporting event, it can be a pain in the ass to switch lenses. Luckily, fossils are not exactly fast-moving, so if well-funded, that's not really a problem.

Don't have a lot of money? Me neither! Zoom lenses work just fine and I've done a side-by-side comparison of photography using my cheap DSLR with a zoom lens, using the same lighting setup, and switching it out with a Nikon D90 with expensive prime lenses and the results are quite favorable. I still like the results with the expensive camera slightly more, but in general most would be hard-pressed to actually tell the difference. One last note: the limiting factor for taking good photos will be the lens, not the camera body. If you've got an expensive camera body with shit lenses, you will take photos that look crappier than an expensive high quality lens on a shit camera body.

A super handy chart showing what different aperture (f-stop), shutterspeed, and ISO settings mean for photos, put together by Daniel Peters.

 Basic tips 3: exposure

So you've got a DSLR and some kind of lens. Just put it on auto and click away, right? No! Please don't. You've got a state of the art piece of technology in your hands, and it is not that difficult to learn how to use it properly! The most important thing to learn is exposure - how to juggle different settings in order to take a photo that is at optimal exposure. First, when you look into the viewfinder you'll see a little bar with a zero in the middle and tick marks for -2, -1, +1, and +2. Exposure is essentially how much light is coming into the camera; the camera is set so that zero is optimal exposure, +1 or +2 is overexposed (too much light), and -1 or -2 is underexposed (too little light). "Ok great, let's just press a button to make exposure zero". Nope, doesn't work that way. Exposure is a function of three different settings on your camera: aperture, shutter speed, and ISO. All of these work with eachother to make great photos but if used at their extremes can produce shit.

When shooting in manual on a DSLR you can adjust shutter speed (upper left), aperture (upper middle), and ISO (upper right), the three of which should be adjusted to attain correct exposure using the little scale in the middle. Adjusting these three to get to zero, and maintaining quick enough shutterspeed to take a non-blurry photograph, is half the battle in photography. From digitalcameraworld.com

Aperture, known colloquially as F-stop, is a measure of how wide the mechanical aperture of the lens is. The lower the number, the wider the aperture - the higher the number, the smaller the aperture. My little zoom lens ranges from f/5.6 at the widest to f/32 at the smallest. At lower aperture, for god knows what reason (this isn't a post on optical science so read elsewhere if curious) the depth of field narrows - this is the band in which everything is in focus. Also, the closer an object is to the camera, generally speaking the depth of field scales so that it is narrower closer to you - hence the difficulty in focusing with your own eyes on objects close to your face. The higher the f-number, the broader the depth of field, and everything tends to be in focus. The flipside is that if you keep everything else constant, a lower f-number (wider aperture) will produce an overexposed image whereas a higher f-number (narrower aperture) will produce an underexposed image - because of the amount of light coming through the aperture (wider aperture = more light). A good strategy is to split the difference: f/16 is what I typically shoot with for small to medium sized specimens as it permits a decent amount of light but also has an intermediate depth of field.

 Which brings us to shutterspeed. This is literally how long the camera shutter is open for, and is fairly intuitive: the slower the shutter speed, the longer the shutter is open, the more light comes through; the faster the shutter speed, the shorter it is open, less light comes through. This compliments F-stop and the two can be used to balance each other: need to shoot at wide aperture? shutterspeed should be higher. Need everything in focus (high F-number/narrow aperture)? shutterspeed should be lower. Here's the best part: the camera (in this case) does all the thinking for you and automatically calculates the ratio for which settings will produce perfect exposure. A little tick mark on the exposure "bar" in the viewfinder will tell you when you've got each setting at an appropriate place - this is called the exposure meter. If you have your F-stop setting where you want it, just move the shutterspeed dial until the tick mark goes right in the middle; it might jump around a little to +/- 0.25 or so, and that's fine. Shutterspeed will be brought up again below on the issue of camera shake.

ISO is a different issue - this is the sensitivity of the digital sensor to light. Let's say you need to take a photo at narrow aperture, but with appropriate shutterspeed, your photos are blurry because you 1) are shooting in some dimly lit mildewy museum basement, 2) either have drank too much or not enough coffee, or 3) need to eat or 4) do not have a tripod. In this case, not enough light is getting in even with a longer shutterspeed, and the long shutter time is letting motion blur from shaking the camera to make the photo blurry. You can increase the light sensitivity of the sensor by increasing ISO. ISO should normally be set low at 100 or 200. For sub-optimal lighting conditions setting it to 400, 600, or 800 can fix most problems, whereas 1600 ISO essentially permits you to take pictures at night. The flipside is that the higher the ISO the more artifacts make it into the picture - all sorts of graininess which looks shit, anomalous blips of color (usually red), and that doesn't really work well for a published picture. For the most part, unless your shooting fossils at night, ISO won't need to go so high as to introduce noticeable artifacts - and even then, raw photos I've taken of the aurora borealis at midnight in Montana can be edited using so that 90% of the artifacts go away. Again, adjusting ISO will be factored into the camera's exposure meter. ISO can generally be left on a fairly low setting if you are shooting with a tripod or camera stand, and is thus mostly relevant towards handheld shooting.

Here's some examples of different photos of a xenorophid dolphin vertebra taken with varying exposure achieved through different means:
 

Handheld, on auto, with flash, f/5.6, 1/40 second shutterspeed, and ISO at 400. There's no lighting from upper left, there's a bit of shine, and some weird shadows which make editing challenging.


Taken in manual and handheld with exposure set to zero, f/32, 1/4 second shutterspeed, and ISO 1600. Camera shake! Even with ISO set so high the image is still blurry. I initially set the aperture to be tiny to get this effect for educational purposes. Setting a wider aperture (down to f/5.6 on mine) would have permitted a faster shutterspeed.


Underexposure! Taken using tripod, underxposed by approximately 1-2 full "stops" - f/16, 1/8 second shutterspeed, ISO at 100.



Overexposure - f/10, 1 second exposure, ISO 100. This actually doesn't look too horrible.


This image is ideal, and made use of a tripod, f/16, 1/5 second shutterspeed, and ISO at 400. ISO isn't needed to be that high for this shot, but from an earlier session I discovered our second floor vibrates when large vehicles drive by outside, meaning camera shake even when on a tripod!


A very basic lighting setup, here photographing a small xenorophid dolphin skull on a white sheet. LED lamp at upper left, camera in foreground.

Basic tips 4: lighting

From the prior section it should be obvious that the most important aspect of photography is getting the correct amount of light into the camera. There are ways around shitty lighting, but you don't have to accept dim lighting and deal with it - you can always bring your own light. Spotlights can be useful, but the bulbs burn very hot and can explode. A cheaper alternative is LED lamps - little banks of 100s of LEDs which can be battery powered or plug into an outlet. These use far less electricity, do not get hot, and are very very portable. Most come with a little miniature tripod, but can also be mounted on their own full size tripod. I have one of these, but at U. Otago we had three or four to use. Light intensity can also be adjusted.

Convention dictates that lighting should come from the upper left in published photographs, so that shading and shadows are consistently in the same direction. DO NOT think this translates to "let's use a single light source in a dark room - we still need to see the lower right side! Ideally, you could use four light sources, and have all but the upper left turned to lower light intensity, with the upper left set higher - this will give maximum lighting of all features and conform to the standard "upper left" rule. Only have two lamps? Put the second one at the lower right, but at lower intensity. Only have one? Ambient lighting can be used for most of it (think low F-stop, slow shutter speed, higher ISO) with your lamp positioned again at upper right.

If you have access to a camera stand with four lamps, "great" - many camera stands do not allow adjustment of the light intensity, and I find most to just be cumbersome and awkward and thus to most museums I bring two tripods and an LED lamp which is ultimately more flexible. Alternatively, diffusers can be used to dim non-upper right light sources, or to soften light that is too "hard" (see below).

If working with larger specimens, lighting can be very tricky - at U. Otago we used several large size sheets of white styrofoam to reflect light. It's not quite as effective as a mirror, but still has a noticeable effect and you can really get light into all the tough to see spots on a large specimen with minimal lighting and lots of white sheets. Tyvek cloth works as well - anything you can reasonably use that is white and reflects lots of light in the direction you need it.


Most LED lamps can be placed directly onto the flash mount of a DSLR camera.

Another trick, if you need to get a lot of reference shots but they do not 1) need to have a nice background or 2) need to have consistent lighting from upper left: if you have one, take your LED lamp and stick it on the flash mount - voila! You now have a consistent light source that doesn't flood your fossil with shiny highlights. Set F-stop down at its lowest possible number, and there will be a "Program" setting where you can set ISO to the desired level, set F-stop where you want it, and the camera will automatically set shutterspeed. If ISO is high enough and F-stop low enough, the shutterspeed will be fast enough to take hand-held shots with your lamp mounted. I've done this a lot and it works great. I first experimented with this on my colleague Rachel Racicot's face at the La Brea Tar Pits. This method also saves your camera battery - and most LED lamps run on batteries (double A). Mine has its own special rechargeable battery AND works on double As, and I use a set of rechargeable double A batteries so that one the regular battery wears down, I put in the double As and put the other back onto the charger, and then recharge the double As when necessary - allowing nearly continuous photography.

Osedax craters in the holotype skull of Waharoa ruwhenua, photographed with ammonium chloride coating and low angle diffused LED lighting. From Boessenecker and Fordyce 2014: Lethaia.


Need to photograph subtle surface texture such as patches of bryozoans, bite marks, or other traces? Use low angle lighting - i.e. place the light source low on the "horizon" of the surface being photographed.

Lastly, any increase in the amount of light you can achieve will 1) permit you to shoot at higher f-stop (and therefore with a broader depth of field so more will be in focus), shorter shutter speed (reducing camera shake and therefore reducing blurriness), and lower the necessary ISO (reducing the number of ISO-derived artifacts in the image). More light = better conditions for photography.

OK one more point: unless you know how to manually tinker with flash, DO NOT USE FLASH. Flash often makes fossils appear shiny and often negates all the careful tinkering you've done to master the f-stop, shutter speed, and ISO above in basic tips 3.

Basic tips 5: tripods, camera stands, and shutter release
Camera shake is a terrible thing, and unless you know how to set exposure, play around with f-stop and ISO to get a working shutter speed, you will end up with shitty, blurry photos that will drive your colleagues insane. Fortunately, tripods are cheap! Mine cost 35$ at WalMart. Stick your camera on a tripod (remember to never over-tighten the screw) and you can take long exposure shots with ease. If crappy lighting is all that's possible, just dial down the f-number and shutterspeed and you'll be able to achieve a decent exposure - just don't cough, bump the camera, or let a train or 18 wheeler drive by. Do not press the shutter button yourself - even if done carefully with a super heavy duty expensive tripod, the pressure being released by your finger on the button will cause the camera to shake. Use the timer - on my camera it can be set to 2, 5, or 10 seconds. I'm an impatient bastard, and my camera makes a horrid beeping sound during it and I use an old school manual shutter release - a cord with a button on the end. The button can even be depressed halfway for autofocus - how about that! Remote shutter releases also exist, but I find them equally irritating as some of them need to be recalibrated with the camera every 10 minutes and have a battery of their own. Also, the remote can be lost or misplaced. Corded ones are cheaper, run off of the camera's battery, and are stuck right onto the damned camera so it's pretty difficult to lose them. Most of this applies to camera stands as well: stands reduce camera shake, but often (especially during museum visits) you might be stuck with inflexible lighting.


A lightmaster lightbox my lovely wife got me for my birthday - rather than use conventional halogen or tungsten bulbs, this one is LED powered and is less than 1 cm thick. Though I'll be using it for drafting and artwork rather than photography.


Our giant light box at U. Otago - an old drafting lightbox the size of a refrigerator. The glass was not frosted, so we just laid down a bunch of large sheets of tracing paper to give it a more diffuse effect; LED lamps can just be placed directly on top like this.


One of the lumbar vertebrae of OU 22163, a juvenile specimen of the eomysticetid Waharoa ruwhenua, photographed on a lightbox with diffused soft lighting from upper left - original photo (left) and edited image on right as used in Boessenecker and Fordyce 2015: PeerJ. With the even background and consistent contrast on the crisp edge and lack of shadows, editing this with the magnetic lasso tool took all of ten seconds.

Want to make editing the photographs much, much easier? If you can, find a large light box - many geology departments will have old large ones used for drafting cross sections and geologic maps, likely to be in mothballs thanks to the use of software like GIS. I'm a bit old fashioned and love to do lots of stuff by hand, and gleefully admit that I still use light boxes for drafting (my lovely wife - Hi Sarah! - got me a spectacular light box for my 30th birthday last fall). Back-lit fossils are super easy to edit in photoshop. What a light box achieves is a continuous light tone around your fossil, which makes editing the image and getting rid of the background (either through the magic wand tool or the magnetic lasso tool) 3-10 times faster. The flipside is that light boxes are expensive. Light boxes do another thing: they seriously increase the amount of light available for your camera - again drastically improving lighting conditions.

Basic tips 6: what to put your fossil on

This may be intuitive: anything you care enough to learn all this crap for is likely important enough that you don't want to damage it during the process of taking photos. If a fossil, use foam! Or sandbags. Since you're not storing the fossil permanently like this it is OK to use non-archival materials for a couple of hours. Fossils should be propped up so they don't fall over. Sand bags and wedges of foam are great for this.

The holotype skull of Tohoraata raekohao perched on a series of sandbags and foam blocks covered by a sheet of white tyvek, with a giant sheet of white styrofoam behind to provide a degree of backlighting for ease of editing, and of course diffused lighting from upper left.

Another consideration is what the background around the fossil will look like. Most are going to crop out the background in photoshop so that the pile of ugly sand bags and other random objects stuck together like a house of cards underneath your fossil aren't cluttering up your published image. How can we make this easier? For smaller specimens on a flat surface that won't stand the way you need , you can use a lump of plasticene clay (which can leave grease on your fossil) or playdough (which does not). It's best to not have any of this material visible to keep editing time down. Another trick is to use sheets of Tyvek, which is super thin and lightweight. For gods sake do not use black cloth! Black cloth doesn't reflect much light and produces much crappier lighting conditions often leading to underexposure of your fossil around the edges or in cracks along the periphery. If you need to build a large pile of styrofoam blocks and sand bags to jug up several bones or a large awkward one into an appropriate orientation, cover the whole thing with tyvek which can settle into all the nooks and crannies and voila! The monstrous 3D support pile you've meticulously constructed is now hidden and easily edited away!

A temporary diffuser made out of an ethafoam sheet and a piece of scotch tape...

Advanced tips 1: diffusers

Hard lighting can cast small shadows that may obscure some detail and increase "local" contrast in spots so that small highlights are overexposed and shadows are underexposed. Using a diffuser can scatter light and produce softer lighting. Diffusers can be purchased, but we're paleontologists - we're ingenuitive and often broke! Make your own diffuser and spend the money on a better lens instead. Diffusers can be made with sheets of vellum, mylar, or even tracing paper - anything thin and semi transparent works. Too much light coming through? Use another sheet! At Otago we had a number of different homemade diffusers made from a card matte from a picture frame with mylar or vellum taped in place, stuck onto a wooden base to keep it upright. Different sizes are great. For a large light that's on a tripod, you don't need to waste time making a four-foot tall diffuser: just get some sheets of mylar or vellum and use artist tape (the blue masking tape) and stick it directly onto your lamp! Also: make sure not to knock your diffusers over onto your fossil during photography if your fossil is precariously balanced. If you're shooting in a museum and don't have any of those types of paper, thin sheets of ethafoam can be used in a pinch.

...and a much better diffuser, seen at left, made out of vellum and a wooden frame. This is a better example since it also showcases the soft lighting produced.

Professional photographers who photograph small (e.g. jewelry) to large objects (e.g. people) often use light tents - which essentially is a 270 degree diffuser that also acts to provide backlighting. I'd love to try using one of these. Here's an example below, and here's a how-to guide on making your own light tent.

A collapsible light tent - from youtube.com.

Advanced tips 2: focus stacking

Can't get a fossil to be completely in focus? Short of increasing the amount of light you have and closing the aperture severely, sometimes some specimens just won't fully go into focus. Luckily there's a technological fix for that called focus stacking. If you take photos under the same lighting conditions with the focus set at different overlapping levels of the subject, you can digitally merge those using Photoshop or another program which takes the parts of your photos that are in focus and merging those whilst ignoring the parts that are out of focus. To take appropriate photos, you can 1) keep the focus fixed on the camera and slide the camera back/forth on a rail (expensive) or 2) just manually adjust the focus, taking 3-10 photos depending on how much of the subject is in/out of focus. Note: this will be more important if shooting with prime lenses at low F-numbers.

Focus stacking: image on left is one of five original photos. In this photo (holotype periotic of Tohoraata raekohao) the parts of the bone closest and furthest away are out of focus, while the middle of the bone is in focus; five photos spanning all parts of the subject were taken and then merged using focus stacking to produce a photograph with continuous focus (right).

Digital merging can be done in Photoshop CS5, CS6, and above, and tutorials for it can be found online - but very briefly, you load individual photos into photoshop as layers (adobe Bridge is the easiest way to do this) within a single PSD file, then go edit->align layers, and once that's done, edit->merge layers. Photomerge doesn't really work too well at this. There are other dedicated freeware programs, but from what I've tried they're all awful. All of my earbone photographs from my Ph.D. thesis on New Zealand eomysticetid whales were shot at different intervals and focus-stacked... literally over 100 different images composited from 4-12 separate photographs.


A large (but by no means the largest!) specimen being photographed in the stairwell at U. Otago; the block is the rostrum of a referred Tokarahia lophocephalus skull, and is positioned right next to the giant penguin Kairuku display case for those familiar with the Otago geology department.

Advanced tips 3: photographing large specimens

Large fossils - some dinosaurs and whales come to mind - pose a whole host of problems. Occasionally fossils are embedded into a wall of plaster or are in some sort of a mount - or worse, in a dark corner in a basement and are too large to move. In these cases, some creativity is needed with lighting and camera angles. For very large specimens, you can either use a very, very tall ladder (if available, say at an oversize facility like UCMP's Regatta building in Richmond, CA, or USNM's Garber facility in Maryland) and photograph the fossil on the ground. This means handheld shooting or the use of a swing arm that can clamp onto a railing. At U. Otago, we had no room for something like that, but we did have a very tall stairwell - so we'd literally place a whale on the floor at the bottom, clamp a camera onto the railing on the second story (first story had ~12 foot ceilings, so the camera was nearly 20' up). All of my photos of eomysticetid skulls for my Ph.D. thesis were taken like this.

If a fossil can be tilted so that you can shoot horizontally, even better! Just go far away from the fossil until everything is in frame and shoot horizontally as if it were a deer out in nature or something. If the specimen is too fragile, this option is probably not a great idea.

Can't fit a tripod or a flood light in because the fossil is too damned huge? Stick a white sheet or a large plank of styrofoam at the desired lighting angle, and aim a spotlight or LED lamp at the foam - and bounce the light off the foam at the desired angle (e.g. upper left). This is a workaround for photographing enormous specimens in cramped areas.

Sometimes you're stuck with a specimen that is too big to shoot from above and too heavy or large to move. The holotype skull of the eomysticetid Tokarahia kauaeroa is such a case - the basement ceiling at U. Otago is about 7' above the floor, and the block needs about six people to lift - it's quite scary to do so, and logistically a nightmare. So, we took photographs from the highest point possible using a tripod, and stitched the photo together. This ended up looking not quite as great as a photogrammetric 3D model I put together, so we ended up just using an arguably undistorted image derived from photogrammetry. Point is - creativity means that there is always more than one way to skin a cat (or dead whale).

An OKish photo of a cow shark upper anterior tooth, shot horizontally at UCMP (Berkeley) with my zoom/macro lens from about three feet away.

Advanced tips 4: photographing tiny specimens

Macro lenses and good lighting mean that you do not need to screw around with cameras attached to binocular microscopes. With a proper macro lens (a type of prime lens ideally suited towards closeup photos) you can take photographs of objects 4-15 mm in size with excellent resolution, no microscope needed. It's a great way to photograph the middle ear ossicles of whales and tiny shark and dolphin teeth.

I have a bit of a "ghetto" macro lens - it's a telephoto zoom lens with a macro lens feature. It can take great closeup images, but only from about 30-40 cm away at the closest. What this means is that it's really awkward to use this on a camera stand, and I have to get up on a chair to look through the viewfinder and risk falling over. So, rather than bother with all that crap, I set up my tripod, light, scale bar, and shoot horizontally on a table top. Problem solved!

Advanced tips 5: light temperature

When I was four I saw a light bulb turned on up close for the first time, and it was within reach, so I reached out my hand and touched it with my right index finger. It took a second before I realized the pain, and within minutes I had a pretty gross blister; I was a stupid child. Light temperature does not refer to how hot a bulb gets. Rather, different bulbs will produce a different color. Tungsten bulbs produce yellow light - and though most cartoons depict the sun as somewhat yellow, it is far from it - a blinding white light. LED lights look a bit blue in comparison to tungsten - but are actually daylight temperature. The point of all this is that if you care enough, it's perhaps best not to mix different temperatures - the two most common being daylight (LED, camera flash, halogen) and yellow light (tungsten bulbs). Note that this does not matter one bit if your final image is going to be converted to black and white. It *might* look weird if going for a color image, but most are not going to notice so this is something I never really worry about.

 Yours truly coating the holotype specimen of the sea lion Neophoca palatina for a paper with Morgan Churchill - coming soon in Journal of Paleontology. Note the glass place and cake turntable below; the glass plate allows blacklighting with a lightbox.

Advanced tips 6: ammonium chloride coating

Fossils that are dark brown or black pose a problem in that little surface detail will be apparent no matter what the lighting conditions are. An old school method to solve this problem is to coat a fossil with sublimated ammonium chloride. Ammonium chloride is mostly harmless and can be placed into a glass vessel that somewhat resembles a crack pipe: ideally it will have a small nozzle followed by an expanded bulb, and then a tube to which you can attach a little air puffer or a slow stream of compressed air. Solid ammonium chloride is placed into the bulb (which is unfortunate since the chemical looks like white powder) and then, even worse - you heat the bulb up over a bunsen burner or other comparable flame. It sublimes - in other words, goes directly from a solid to a gas - and a gentle puff of air pushes the gas out the nozzle, and onto your fossil - where it sublimates back into a solid, giving a very thin coating of white. This coating is easily removed with water - make sure your fossil can take a brief and gentle soaking to remove the ammonium chloride. Be careful though, it will come off on your fingers - meaning another spraying is in order. Some practice is necessary to get a nice even coating. Another tip: you do not have to start over fresh for each view. I would spray as much as possible on the first try, take the photo, flip the specimen, spray the other side, and repeat until everything is photographed. Remember the focus stacking described above? Each of my eomysticetid whale earbones was ammonium chloride coated AND focus stacked. Goddamn that was a lot of work. This is sort of unnecessary if you can publish in color, unless a fossil is really, really black like the inside of a black hole (phosphatized bones/teeth for example).

Bunsen burner and ammonium chloride in the glass tube, chemical is present in the bulb - you can see a bit of whitish gas escaping: this is what is blown onto the fossil.

Quick note: if shooting with backlighting on a light box, you do NOT want to pick up the fossil and so at Otago we would place the fossil onto a sheet of glass, coat it, and place the glass onto the light box so the light can still shine through.

At other institutions that will kindly remain unnamed, some sort of aerosol can spray crap has been used as a shitty alternative to ammonium chloride - but unless removed immediately, this stuff becomes rock solid and will not be easily removed except with diligent scraping. I've seen many fossils unnecessarily and potentially irreversibly harmed this way, and the hardened paint-like substance is nearly more difficult to remove than the actual rock the fossil was initially entombed within. Please, for the love of god, do not abuse your fossils like this!

Advanced tips 7: shooting in raw

DSLR cameras can shoot in two modes: they will save a jpg "preview" file - the image most digital cameras will produce - as well as a "raw" file. Raw files are difficult to edit and only a few programs can actually open them, and even those do not permit the image to be permanently tinkered with. Raw files are great because they can be adjusted and a jpg or tiff file generated from them, but no information is lost. In other words: if you want to increase contrast in a jpg and save the file, you lose information from that image and it is altered forever unless you have an original backed up someplace. With a raw file, the "sliders" in the program can just be reset and the image is never permanently altered. Essentially, raw files are "archival" image files. The flipside is that raw files are large, and may be a bit cumbersome to edit, and require specific image editing software. Different camera companies use different file types: Canon (what I use) uses CR2 files whereas Nikon uses NEF. Adobe Bridge can open up some (NEF). I personally hate software that isn't free, so I use the very flexible freeware program "RawTherapee". A word of caution: shooting in raw takes a lot of harddrive space; my Ph.D. dissertation folder on my computer has nearly 20 gigabytes of photos thanks to raw files.

Advanced tips 8: efficiency

Lastly, a word on efficiency. A good lighting setup can take anywhere from 10 to 45 minutes to set up, depending on how much room you have to set up, if you have help, or alternatively, have somebody in your damn way or distracting you. Or if all of a sudden it's afternoon tea and it would be rude to continue shooting. It takes a while to set up all of this crap, and it's not fun. Many, many arguments with my lovely wife were started by me taking too damn long to take all my thesis related photos on campus during my Ph.D. Hours spent taking photos without food or water plus bright lights is a great cocktail for a massive headache.

So: get an assembly line started and photograph everything you can over a few hours. This also really helps if you need to maintain consistent lighting; you may very well not remember how to mimic a certain lighting setup you had before (take a cellphone picture). This is especially relevant if you are taking ammonium chloride coated photos.

Don't get too caught up in the details; it's simply not possible to produce a perfect photograph, though many will try under the delusion that it is reachable. If you begin to think that you're wasting a lot of time doing some of this, perhaps you're right! Think about how you could work around a particular problem or how to be more efficient. Photography is not art - I'm sorry to photographers, but after doing a fair amount of it, it takes a tiny fraction of the amount of skill required for fine art. What I mean is this: there's nothing really special about it, and a fair amount of judging of photograph quality is a bit of a black art and fades quickly into the realm of minute subjectivity. Photography is easy to learn, and anybody can read what I've written and use these tips to produce better quality images. Photography is mostly scientific, but bending the rules to get a better picture - or the same quality picture for less effort - requires a bit of creativity.

Further reading:

The Fossil Forum: Fossil Photography subforum

Photographing fossils PDF by Wayne Itano 

Photographing Burgess Shale Fossils by Royal Ontario Museum

High Dynamic Range photography in Paleontology by Jessica Theodor and Robin Furr in Palaeo Electronica

Thursday, February 11, 2016

Paleontological research tips II: field notes, continued

Here's the second part in my series, and admittedly, it's a (short) continuation of the first post on field notes - a couple of additional tips, and what to do after the field with notes and specimens.

Q: What do you do with field notes after you're back from the field?

A: Keep them. Forever.

My dad is an attorney, and there is a similar problem in law: a full paper trail documenting all aspects of a given legal case is required to be kept by the attorney for 10 years. My dad does get a bit of business, so growing up I was a bit confused about why we had so many banker boxes filled with boring legal documents sitting in our garage. About once a year, he'd go out and dispose of whatever case files were over 10 years old. It's a pain, but it's got to be done in order to "cover your ass", so to speak. Fortunately in science we don't quite have that same level of paper to churn through - in a decade of research I've filled up about a dozen field notebooks and a half dozen moleskine lab notebooks - it won't even fill up a single banker's box. But here's the catch: in science, there is no statute of limitations. We've got to keep our notes forever; the best way to go about this is to literally deposit your notebooks - or a copy of it - with the institution housing the material the notes are associated with. Disclaimer: I still haven't actually done this for UCMP, but have transcribed all the notes for individual specimens that are now in their collections - so they have all the information, just not in notebook form. This way, in case your house burns down, or your cat pees on your stuff (it happens, trust me) there is another copy someplace. An even better idea - scan your notebooks to pdf; I did this with all of my notebooks before leaving NZ.


Here's all of my notebooks - see, you don't throw them away when you're done. Safeguard them!

Traveling? I always carry my notebooks on my person - I NEVER trust the airline (or shipping company) to do the right thing. So, my bookbag coming to/from New Zealand was a bit heavy, as I literally carried every single one of my notebooks on me rather than risk the fate of losing them if my bag was misplaced, stolen, or just got wet or damaged. I once had a partial fossil baleen whale skull from a tidepool in Santa Cruz - shipped as a checked bag (well, cardboard box) - sit on the tarmac overnight in the rain at SETAC on my way back to Bozeman for spring semester. Now, the skull was fine because 1) it sat in a tidepool for probably a century and is fairly immune to water (it was covered in algae and barnacles and smelled HORRENDOUS when it was delivered the next day, but that's another story) and 2) is in a concretion and practically indestructible. But say that had been a non-waterproof duffel bag with handwritten notes in it? Sayonara! My buddy Lee Hall has lost his checked luggage while flying to Canada twice (once at the 2006 Ottawa Society of Vertebrate Paleontology meeting, including all of his nice clothes) and luckily got all of his stuff back the first time (can't remember if he got his bags back the second time). Losing clothes (and field gear the second time) is frustrating enough - but it could happen if something really important is placed in checked luggage.

Moral of the story: don't trust yourself to be the only steward of data. Scan it to pdf, email it to the host institution (or print it out and snail mail it to them), upload the pdf to cloud storage if you're really paranoid.

Q: What do you do with fossils after you're back from the field?

A: A bit more nuanced than the answer above. I'll explain more.

Presumably you've followed my advice from the prior post and have started using field numbers for fossils - if so, great! If not, go read it again and reevaluate why you want to be a paleontologist - professional or otherwise. Now, after returning triumphantly from the field, your first interest (aside from taking a shower and sleeping) might be to start preparing the fossils. And that's fine - this is the stage of the process where you can paint numbers onto a smooth exposed surface. I recommend sticking with archival materials - use acrylic white paint and an archival micron pen to write with. Now, if you still need your field notebook - or if your notes are in shorthand, as mine are - you're going to need to transcribe them somehow in order to keep that data physically associated with the fossil. You can write out the field number, collection collector, date, identification, location, and stratigraphic level onto a small sheet of paper - these are the basics, and many museum databases do not give the opportunity to include intra-formational stratigraphic data, so including this information will help future researchers interested in higher precision data use your fossils.




Here's an example of one of my specimen cards: I print out 6 of these on a letter size sheet (single sided, of course). It's got all the basics: ID, museum specimen number, field number, locality number, collection date, plus a more specific description of the locality and stratum.


Or, if you're more organized and prefer something standardized, you can use pre-made collection sheet forms that are small enough to fit all relevant data that 1) links the field number and museum number and 2) also includes more detailed information that cannot easily be included into a database. I'll admit I got the idea for mine from seeing these sheets in UCMP collections filled out by marine mammal paleontologist Ed Mitchell (the guy who named Valenictus, Imagotaria, Allodesmus kelloggi, and Llanocetus denticrenatus) and used a similar approach.




A distal humerus of the walrus Dusignathus collected this summer by Dick Hilton during fieldwork in Marin County. It's a future UCMP specimen, but until it is formally accessioned there it can be tied to relevant data by my field number - RBPR-46 (meaning Robert Boessenecker Point Reyes), written on the swatch of acrylic paint at the upper left corner of the specimen in this photo. When the specimen is formally accessioned, the field number stays and can be checked across my field notes years from now.


Some other tips:

-Don't write field numbers in permanent ink, and don't write directly on the bone; according to work done by former Museum of the Rockies artist-in-residence Michael "Spiff" Holland, if it ever goes on display the only way to get around permanent ink written right on the bone is to paint over it, with a matching "bone" color. A swatch of white acrylic paint is fine, and can be removed if you so desire.

-If you prepare multiple fossils at the same time, make sure you keep something clearly indicating what field number belongs to a particular specimen until the time comes when you can paint a label onto it. Preparation is the easiest stage at which field numbers can disappear. I tend to keep incompletely prepped fossils sitting on their actual field ziplock bag until they're fully prepped and labeled.

-What if a fossil is too small to write on? Use a smaller plastic bag and write on that! There are archival tiny plastic bags (and yes, they do resemble the ones drug dealers use) that can be used. If a fossil is super super tiny, I use two-part ~250 mg pill capsules and cut out a tiny rectangle of index card and write the field number in archival ink. And because the capsule is still tiny, I then put that inside a smallish bag and write on that too.

Sunday, January 24, 2016

2015 in review: Advances in marine mammal paleontology

Welcome to the fourth annual review of advances in marine mammal paleontology! Similar to 2014, there were just over 50 new papers. I've managed to read most of them in detail, and am sufficiently caught up in reading that I can take a break and read some of what's come out in 2016. I'll admit that I spent most of winter break relaxing, visiting museums, and doing fieldwork - and as a result at least 1/2 or 1/3 of this has been typed up since January 1st. My apologies for being about three weeks late. Also, you're welcome.

As usual, I'm sure I've missed something. If so, let me know, and if I'm not too sick and tired of working on this, I'll go ahead and add it in. 




In the 1980s Daryl Domning and Christian de Muizon reported a small sirenian rib from the Pisco Formation of Peru, one of the few records of dugongid sea cows from the Pacific coast of South America. Years later it was more precisely identified as a rib of the small sea cow Nanosiren, but considered to be strange in comparison to most other sea cows. This new study by Eli Amson and others took a histological slide from the rib and compared it with sirenians and the aquatic sloth Thalassocnus. Sea cows typically have an unremodeled layer of sheet-like cortical bone with an inner zone consisting of remodeled "secondary osteons"; Thalassocnus lacks this parallel-sheet like zone and instead the entire cross section consists of remodeled bone. The mystery rib matches the histological pattern of Thalassocnus, and is reidentified by the authors as an aquatic sloth rib. The authors point out that the most highly specialized aquatic sloths now do not overlap stratigraphically with sea cows in the Pisco Formation, suggesting that the sea cow niche was occupied by Thalassocnus after sirenians went extinct in the western south Atlantic.


This new study reports a fragmentary mysticete mandible from the Azores Islands off the coast of North Africa from Pleistocene strata. This mandible is not complete enough to identify to the family level, but is significant owing to its geographic location and strange bone modifications. It has a series of large pits on one surface, which appear to be anatomically genuine (e.g. ante-mortem rather than post-mortem) and thus not taphonomic in origin. The authors point out that relatively few fossil cetaceans have been reported from small oceanic islands, and hypothesize that such occurrences are likely underreported. However, it's worth noting that small islands are unlikely to have large sedimentary basins and that most small islands have Cenozoic strata formed as "bathtub ring" deposits where the abundance and ease of discovery for fossil cetaceans is likely going to be rather low in comparison to continental margin deposits. Then again, cetacean bones are not small (quite the opposite) so there's always a trade off.




Desmostylians are some of the most wonderfully bizarre of all marine mammals. Well known Miocene forms like Desmostylus, Paleoparadoxia, and the recently split-off Archaeoparadoxia and Neoparadoxia, are so derived that it's difficult to pick out exactly which group of plodding semiaquatic herbivores they belong to. Tradition dictates that they're tethytheres, most closely related to sirenians and proboscideans - but the possibility remains that they're perissodactyls. More fossils of early desmostylians are needed, and in 1986 Daryl Domning, Clayton Ray, and Malcolm McKenna published some late Oligocene specimens from Oregon that my hero Doug Emlong had collected - some mandibles and other elements, upon which they erected two species - Behemotops proteus and Behemotops emlongi - the "Behemoth face". None of the skull was known, but the more primitive teeth permitted the authors to link desmostylians with the anthracobunids, hippo-like relatives of early elephants. Later finds of Behemotops led the same authors to reevaluate the more fragmentary species B. emlongi and synonymize it with B. proteus. Still, no skull was known - until Brian Beatty and Thomas Cockburn reported this new specimen of Behemotops cf. proteus with most of a skull, some teeth, and quite a bit of the postcranial skeleton. The new specimen indicates that the rostrum was unusually elongate and narrow, similar to Cornwallius. The rather wide "shovel jaw" of B. emlongi is proportionally much wider than the rostrum of Behemotops cf. proteus, and so these authors erected the new genus Seuku to house the other species - Seuku emlongi. These Oligocene desmostylians indicate that several different desmostylians inhabited the same area at the same time - Cornwallius sookensis, Behemotops proteus, and Seuku emlongi - apparently coexisted in the Pacific Northwest, paralleling ecological diversity in sea cow assemblages.



This textbook is the best edition yet - the first edition came out in 1999, and the second edition came out in 2006. This text deals with most aspects of the biology and evolution of marine mammals, and gives a comprehensive summary of the phylogeny, anatomy, and adaptations of all marine mammal groups (modern & extinct), serving as an excellent introduction to graduate students interested in marine mammal paleontology. I got a copy of the second edition at the SVP benefit auction in Ottawa (2006) and read the entire front half - the second half, focusing more on soft tissues, diving behavior, and ecology and conservation is less relevant towards paleontologists. The third edition has nearly completely revamped the phylogeny and skeletal anatomy chapters, and many up-to-date references have been added. To my surprise, many citations of my own work were included - I'm young enough to still suffer from a bit of impostor syndrome, so seeing my papers referenced in a textbook is quite surreal. Several of my illustrations have been included as well, which I was quite pleased with! I highly recommend this for any "student" (in the broad sense) of marine mammal evolution.

 


The fossil record of pinnipeds was dominated by taxonomic confusion for nearly a century because most fossil pinnipeds - particularly the phocid seals - were named based on isolated postcranial bones and referred to the same species based on dubious criteria (see below, Koretsky et al.). Pinniped paleontology began in earnest in the North Sea, principally with true seals (Phocidae) and the overly confusing taxonomy of walruses (see my series on the walrus fossil record, hereXXX). Pliophoca etrusca, a Pliocene phocid from northern Italy, is a notable exception as the holotype is a partial skull with associated cervical, thoracic, lumbar, sacral, and even caudal vertebrae, as well as forelimb and hindlimb elements. However, it was originally reported in the 1940's and has been needing a modern "treatment" - which is exactly what this study provides. Pliophoca is very similar to extant Monachus (Hawaiian, Mediterranean, and the extinct Caribbean monk seals) but differs in several cranial, dental, and hindlimb features - such as having narrow, compressed incisors. This study reports many new specimens of Pliophoca cf. P. etrusca including mandibles, isolated teeth, and ankle bones, from Italy, France, and Spain. Previously, other material from the early Pliocene Yorktown Formation of North Carolina was referred to Pliophoca etrusca, but the authors rightly point out that no comparisons were made and no anatomical features linking the two were identified. Cladistic analysis fails to corroborate identification of this east coast USA material, which appears to represent an unnamed monachine instead; true Pliophoca is closely related to Monachus, sharing common ancestry and indicating origin of the Pliophoca-Monachus clade in the Mediterranean during the Plio-Pleistocene. This was followed by dispersal to the Caribbean, and later to the tropical Pacific.







The Pisco Formation is a spectacular Miocene shallow marine deposit in coastal Peru with excellent exposures of diatomite, sandstone, and mudrocks with skeletons of marine vertebrates littering the desert. Preservation is generally quite comparable to that of the Monterey Formation in central California in terms of preservation (i.e. abundant well-preserved skeletons with high rates of articulation), one of the only other stratigraphic units in the world where fossilized baleen has been reported - yet central California is not desert and is instead well-vegetated, relegating most exposures to difficult to access coastal outcrops. These two studies report highly detailed maps showing the occurrence of vertebrate fossils at two of the more important localities in the Pisco Formation: Cerro Los Quesos (cheese hills) and Cerro Colorado (red hills). The study at Cerro Los Quesos indicated that an earlier study conducted by young earth creationists failed to identify many smaller non-baleen whale fossils (small odontocetes, pinnipeds, birds, bony fish, sharks) calling into question the rigor of their field methods. At Cerro Los Quesos, the sheer majority of marine vertebrates are present within a 160 m thick section of the Pisco exposed at the tops of these hills. Again, at Cerro Colorado, marine vertebrates are concentrated into a narrow stratigraphic band (nearly 90% of all marine vertebrates from Cerro Colorado were found in a 35 m section near the base of their column). Both of these carefully executed studies fill in a desperately needed baseline for basic data in one of the world's premier marine vertebrate lagerstätten which, until the past year or so, was being supplied entirely by studies published by young earth creationists.




In the late 19th century a local found a large cetacean skull eroding from a cliff of the late Miocene Monterey Formation near Santa Barbara in southern California. It slowly eroded out over 30 years before being excavated in 1909. It was named Ontocetus oxymycterus by Remington Kellogg in 1925, who recognized it to be a very small part of a very large sperm whale. The tip of the snout is preserved with about ten upper alveoli, and the anterior tips of both mandibles with several poorly preserved teeth. The type species of Ontocetus, Ontocetus emmonsi, is not a sperm whale but is in fact a walrus and a senior synonym of Alachtherium and Prorosmarus. Because of this, O. oxymycterus needed a new genus name, and these authors provide a much needed redescription of this fragmentary but fascinating whale and rename it Albicetus oxymycterus. The teeth of Albicetus are enormous – 8 cm in diameter, roughly ¾ the size of the giant sperm whale Livyatan melvillei from Peru. I always assumed that the snout of this gigantic whale was incomplete, but these authors interpret the rostrum to be more than ¾ complete, and when plugged into body size calculations for odontocetes, a body size of 6 meters (~20 feet), small in comparison to the 10-14 meter length estimate of Livyatan despite the rather large teeth. The teeth of Albicetus, like Livyatan and other members of the “Scaldicetus” tooth grade, has enamel caps on the teeth. Given its size and robust enamel-capped teeth, Albicetus is probably another large macroraptorial apex predator like Livyatan – though in my opinion perhaps somewhat underestimated in terms of body size. 




The fossil record of eared seals (Otariidae) is limited and mostly consists of a few primitive fur seal-like species from the latest Miocene and Pliocene of the Pacific basin in comparison to their higher modern diversity and wider geographic range. The oldest known fur seals, Pithanotaria and Thalassoleon, are only known from the late Miocene of the North Pacific (California, Japan) and are no older than about 10 Ma in age; otariids evolved from an enaliarctine ancestor similar to Pteronarctos, but the youngest enaliarctines are much older - early middle Miocene, about 17-16 Ma. This ~7 million year gap in the mid Miocene begs the question "where the heck did otariids come from?" and "where were they in the middle Miocene?" Morgan and I published this paper after I discovered a partial mandible from the early middle Miocene Topanga Formation (~17.5-15 Ma) hiding in collections at the Cooper Center in Orange County. This specimen was misidentified as the small walrus Neotherium, but differed in having greatly simplified teeth and being much smaller - it was almost on its way towards being a typical late Miocene otariid, but retained an extra cusp on the lower molar lost in all other otariids (the metaconid) as well as primitively retaining a second lower molar. We named this new transitional pinniped Eotaria crypta, referencing its early age, and also its rarity - no specimens of true otariids have yet been reported from the ridiculously oversampled Sharktooth Hill bonebed, nor from well-sampled middle Miocene rocks in Japan. The earliest otariids may have been primarily pelagic, rarely straying into shallow shelf waters - a hypothesis originally proposed by our Japanese colleague Naoki Kohno.

 


The “river” dolphin Parapontoporia is widely known from the late Miocene and Pliocene of California, known from three species, and found exclusively in marine rocks. Its relationships have been elusive, and when first described originally thought to be similar to the La Plata River dolphin Pontoporia and placed in the Pontoporiidae – though similarities with the earbones of the now-extinct Yangtze River dolphin Lipotes were noted by the author. More recent studies utilizing cladistic methods have consistently identified Parapontoporia as a lipotid dolphin with no close relation to the pontoporiids (though the family is known from Pliocene rocks of the Atlantic states, and widely within South American fossil assemblages). Lipotes was completely riverine, which begs the question: why, when, and where did the lipotids become adapted to freshwater? In 2011 I found a single earbone, originally misidentified as a delphinid dolphin, hiding in fossil collections at UCMP in Berkeley. This earbone – the petrosal – is very distinctive, and closely matched those of Parapontoporia. However, this earbone was recovered from the non-marine Tulare Formation, which is late Pliocene in age, from the Kettleman Hills in the San Joaquin Valley of California. The valley was an ocean basin with a narrow connection until about 2 Ma when uplift of the Sierra Nevada introduced more and more sediment into the basin, along with uplift of the coast ranges which closed off the connection to the sea. At the time this individual of Parapontoporia died, the inland sea had transformed into a large lake or body of brackish water fed by rivers. This discovery not only indicates that palaeontologists in California should more closely search Pliocene terrestrial deposits for marine mammal remains, but that freshwater living may have characterized Parapontoporia in addition to Lipotes, heralding modern behaviour and distribution as far back as the late Pliocene.
 

 
[This is the third publication of my Ph.D. thesis - and one of the biggest chapters.] The history of study of eomysticetids is a bit convoluted - first formally recognized in 2002 with the publication of Eomysticetus, the most primitive toothless baleen whale. Eomysticetus was reported from the Oligocene of South Carolina, right here in the Charleston area - it has a mix of archaeocete-like features (e.g. tiny braincase, primitive earbones, large sagittal and nuchal crests, anteriorly placed blowhole, large fan-shaped coronoid process, "pan bone" on the mandible) and many derived features unique to modern baleen whales (rostral kinesis, flattened palate, toothlessness, beam-like mandibles without a fused symphysis). As it turns out, the story of eomysticetids really begins 70 years earlier with the discovery of an unassuming mysticete braincase in the Milton Lime Quarry in south Otago, about a half hour's drive from Otago Campus. It was named Mauicetus parki by Prof. Benham in the late 1930s; 20 years later, Prof. B.J. Marples discovered several mysticete skeletons in the Kokoamu Greensand and Otekaike Limestone of north Otago - and named all these as species of Mauicetus. One of these, Mauicetus waitakiensis, was reidentified as an eomysticetid and placed in the new genus Tohoraata last year (Boessenecker and Fordyce 2014). The most complete of these, Mauicetus lophocephalus, had an Eomysticetus-like skull; more recently, additional preparation and new specimens of Mauicetus parki shows that it is actually in the stem Balaenopteroidea - a "Kelloggithere", or cetothere sensu lato - poorly known baleen whales that are structurally similar to Parietobalaena. Because Mauicetus parki (the type species) and M. lophocephalus belonged to different families altogether, a new genus name was needed for the latter - but, always a complication: sometime in the 1960s an enterprising mover involved in moving the Otago Zoology dept. collections threw away the holotype skull of M. lophocephalus in the garbage, and is now likely in a landfill within 20 km of campus somewhere. R.E. Fordyce started collecting eomysticetid specimens from the Kokoamu Greensand and Otekaike Limestone in the early 1990s, and found at least one specimen (OU 22235) that is congeneric but with some tympanoperiotic differences (the tympanic bullae and postcrania of the type specimen were indeed spared by the ever-so-talented university movers) and another specimen (OU 22081) that was morphologically inseparable from the remaining elements of the type specimen. So, we named the first specimen as the holotype of Tokarahia kauaeroa, a beautiful Eomysticetus-like skull with a significant amount of postcrania, identified the second skull as a referred specimen of Mauicetus lophocephalus, and referred lophocephalus to Tokarahia, recombining it as Tokarahia lophocephalus. Tokarahia is structurally similar in terms of skull morphology to Eomysticetus but principally differs in having a longer occipital shield and more derived postcrania; Tokarahia kauaeroa has a beautiful mix of basilosaurid-like and modern mysticete-like features in the well-preserved tympanoperiotics and postcranial skeleton, and is a spectacular example of a transitional fossil. Most significantly, a single tooth with a flattened was found near the maxilla of the referred T. lophocephalus, matching the size and shape of maxillary tooth alveoli in other eomysticetids - suggesting that eomysticetids like Tokarahia retained a vestigial dentition, now representing an additional intermediate stage between the tooth/baleen bearing aetiocetids and the completely toothless crown Mysticeti.





At the time this study was published, eomysticetids from New Zealand (4 species: Tohoraata, Tokarahia), Japan (Yamatocetus canaliculatus), and South Carolina (3 species: Micromysticetus rothauseni, Eomysticetus spp.) were known, probably indicating a worldwide distribution with at least some local diversity (3 species from the lower Duntroonian stage of New Zealand, for example). Most of these are singletons – known by a single specimen (Micromysticetus rothauseni is a notable exception), meaning that patterns of adult variation and ontogenetic variation are unknown. This largely characterizes the cetacean fossil record in general, and particularly for Oligocene cetaceans. This study reports another beautifully preserved eomysticetid, Waharoa ruwhenua, represented by three partial skeletons including well preserved skulls, mandibles, and tympanoperiotics. The genus name Waharoa means “long mouth” in Māori, whereas the species name ruwhenua means “shaking land”, referring to the English name of the type locality - “The Earthquakes”. The adult has a very long surfboard-shaped palate, which is proportionally shorter in the two juvenile specimens, indicating that it nearly doubled in its length (relative to the width of the skull). Similarly, the mandible elongates as well from juvenile to adult. The tympanoperiotics are nearly adult-like in the juveniles, but the tympanic bulla appears to grow somewhat in size – a novel discovery amongst cetaceans, modern species of which all seem to be born with fully adult size earbones. These changes and  others reported in this study are among the first ontogenetic changes reported for any Oligocene cetacean. Additional features – and the ontogenetic trend of palate lengthening – permit inference of the feeding behavior of Waharoa. The anterior ¼ of the palate is barren and lacks palatal vascularization, suggesting that baleen was only present along the posterior ¾; the lengthening of the palate (more extremely than in any extant mysticete) suggests that extreme length is selected for in eomysticetids, and a feeding adaptation – rather than widening of the palate as in rorquals (minke, blue, humpback whales). Furthermore, the jaw joint appears to have been synovial and differs from the robust jaw joint of modern rorquals which permits extreme opening of the mouth, rotation of the jaws, and dislocation of the jaw joint – all this points towards Waharoa not being able to lunge feed like modern rorquals. Instead, the lengthening of the palate could be analogous to rostral arching of right whales as a strategy towards maximizing the cross-sectional area of the filter feeding apparatus – an adaptation for skim feeding. On our cladogram, right whales are the next diverging lineage after eomysticetids – potentially indicating that skim feeding is the primitive mode of feeding for baleen whales.



  
 Fossils of oceanic dolphins (Delphinidae) are not exactly common in late Neogene rocks of the eastern North Pacific. This family is the most diverse and widely distributed modern group of cetaceans and can be found in every ocean basin. Delphinids are widely known from north Atlantic and Mediterranean Plio-Pleistocene fossils, but are virtually unknown from the late Miocene except for a few fragmentary specimens from Japan (Eodelphinus) and California (unpublished). Given this background, I'm very interested whenever evidence turns up in California of fossil delphinids, since they are quite rare in Pacific margin sediments. In 2009, photos of a rather enormous skull which I at first thought was a monstrous beluga turned up in my email inbox; within a few days I had the collector on the line and he agreed to donate the specimen to UC Berkeley. Sometime later that summer I looked at a private collection and noticed two rather large pilot-whale like earbones, which the collector agreed to donate to UCMP as well. Most odontocetes from the late Miocene and Pliocene of California are small - porpoises, the "river dolphin" Parapontoporia, small delphinid dolphins, with only occasional evidence of early belugas and sperm whales. This rarity of large odontocetes, especially in the Purisima Formation of California - makes me quite interested whenever I stumble across any fossil evidence. After some preparation with an airscribe at Museum of the Rockies in Bozeman, Montana (where I was a student at the time), I found that the skull was actually rather similar to pilot whales (Globicephala) and false killer whales (Pseudorca) rather than extinct belugas (Denebola). The skull was found as float, but is almost certainly younger than 5.3 Ma and older than 2.47 Ma based on associated matrix and its likely stratigraphic position; the earbones (petrosals) were found in situ within a bonebed dated to 3.5-2.5 Ma. I initially thought the petrosals were from the same species as the skull, but a linear regression of petrosal size and skull size amongst delphinoids indicates that the petrosals are too small to belong to the same species as the skull - potentially indicating that two species of globicephalines inhabited the California coastline during the Pliocene. These new fossils, in concert with published fossils, indicates that globicephaline dolphins were already widely spread around the world by the early Pliocene.




Desmostylians are a bizarre but progressively more publicly beloved group of extinct marine mammals with hypothesized affinities to sea cows and proboscideans. Vaguely hippo-like with a conveyor-belt like tooth replacement seen in elephants and sea cows, and hippo-like tusks, desmostylians are inferred to have fed on sea grasses and kelp. The clade was never diverse, but new specimens are always being found and new material from the lower Miocene Unalaska Formation of Unalaska Island in the Aleutian island archipelago of Alaska appear to represent a new species. The new material includes a rather gigantic mandible similar to Desmostylus and Cornwallius, and several more fragmentary specimens. Based upon some minor differences with Cornwallius and Desmostylus, the new genus and species Ounalashkastylus tomidai was named. Another gigantic mandible known only as the Sanjussen specimen from Hokkaido is reidentified as a western Pacific occurrence of Vanderhoofius, formerly reported from the middle Miocene of California. The separation of Vanderhoofius from Desmostylus has been questioned before, but a distinguishing feature suggested by these authors is the loss of lower incisors during postnatal ontogeny; indeed, the upper incisors (but not lower) are lost by Desmostylus and Cornwallius during postnatal ontogeny. These desmostylines also bear large bony prominences on the medial side of the mandible but do not house unerupted teeth, and their function has remained unclear; this study suggests that either 1) the dense bone serves as ballast to keep the head negatively buoyant during feeding or 2) the bony prominences help buttress the mandible as the animal “clenched its teeth” together during suction feeding.  





The diet of pinnipeds is well-established for modern species, but it's difficult to determine the diet of fossil pinnipeds. For modern species we can go watch them eat – or we can cut them open when they die and look at what's in their stomach. For example, before we observed leopard seals filter feeding like crabeater seals, dead leopard seals with bellies full of krill had been found. Diet in fossil pinnipeds is difficult because we certainly cannot do the former, and the latter is rare – only one fossil pinniped with preserved gut contents has been recovered, the phocid seal Kawas from Patagonia. Diet, or at least feeding behavior, can be inferred some cases from feeding adaptations. Many pinnipeds feed in a similar fashion on fish (sea lions), whereas some others are primarily suction feeders that don't really use their teeth (walruses). Can diet be inferred from feeding morphology in extinct pinnipeds? This new study attempts to answer this question by using principal components analysis (PCA), hierarchical cluster analysis (HCA), and discriminant function analysis (DFA) to examine trends in tooth spacing and crown size, and diet. The DFA only reported a weak relationship with diet, and a stronger correlation between tooth spacing/crown size and feeding behavior (e.g. prey capture strategy. Tooth size and spacing were most strongly correlated with how important teeth were in prey capture, with narrowly spaced large teeth present in “biting” pinnipeds, and smaller, spaced out teeth present in “sucking” pinnipeds. Smaller tooth spacing and larger crowns also characterized pinnipeds that rip prey into pieces or filter feed (e.g. leopard, crabeater seals). This study applied these features to the extinct pinnipeds Desmatophoca and Enaliarctos, and recovered both as being similar to modern otariids – generalist feeders like sea lions and fur seals.  



Pinnipeds – seals, sea lions, and walruses – are a group of mammalian carnivores that evolved from dog or bear-like ancestors (or possibly otter-like – e.g. Puijila darwini). Modern pinnipeds are all either suction feeders or pierce feeders – teeth are used only to capture prey, but prey is swallowed whole instead of being chewed (masticated). Enaliarctine pinnipeds – the earliest known seals – have carnassials like terrestrial “fissiped” carnivores. Modern carnivores chew their food, and the carnassials shear through bone and flesh during mastication. Did enaliarctines chew their food like their terrestrial ancestors? And if so, did they have to leave the water to masticate after prey capture? To address these questions, data similar to that collected for modern and fossil pinnipeds as in Churchill and Clementz (2015: see above) was analyzed using principal components analysis (PCA) and phylogenetic independent contrasts (PIC) to see where Enaliarctos plotted within 2 dimensional "morphospace". Enaliarctines occupied an intermediate morphospace between terrestrial carnivores and pinnipeds, retaining close tooth spacing of "fissipeds", but with reduced heterodonty of pinnipeds. PCA indicated that Enaliarctos grouped with other pinnipeds as a pierce feeder - and that it likely did not masticate; this indicates that pierce feeding likely arose as a common feeding behavior of pinnipeds early during their evolution. Lastly, this suggests that Enaliarctos did not need to return to land after catching fish in order to feed, as suggested by some earlier studies. This article also gives a fantastic review of dental evolution of pinnipeds, supplementing earlier discussions by Boessenecker (2011) and Boessenecker and Churchill (2013). There's a common theme here: Morgan and I really like seal teeth!




On rare occasions vertebrate skeletons will get preserved with the remnants of their last meal. The identity of the gut contents associated with the Triassic dinosaur Coelophysis has been debated to death: are smallish bones found within the ribcage of an adult Coelophysis skeleton bones of a different species, or bones of a juvenile? Because the latter would make Coelophysis a cannibal. Fossilized examples of gut contents are rare, but provide pretty powerful data on trophic relationships - in other words, "who ate who". Examples of fossil marine reptiles with gut contents abound - from the Cretaceous of Kansas alone there is evidence of virtually every imaginable trophic relationship amongst large marine vertebrates. However, until this year there was very little evidence of gut contents for marine mammals. Two basilosaurids have been discovered with gut contents (Dorudon - published; Basilosaurus, not published) and two pinnipeds (phocid seal, New Zealand - private collection, not published; Kawas, published). Within Neoceti (baleen whales and toothed whales) there were no known examples. This new study reports fossilized gut contents of a late Miocene cetotheriid baleen whale from the Pisco Formation of Peru consisting of a mass of fractured fish bones tucked between the ribs of a partial baleen whale skeleton. The entire skeleton was not excavated by the authors, but the mass of fish bones was documented in situ and removed. The fish material consists of a single skeleton of a sardine, Sardinops; while the bones are fractured and disarticulated, they show no evidence of partial acid digestion. The authors interpreted the fish remains as being within the forestomach at death (whales are artiodactyls and thus have chambered stomachs). The authors interpret this as indicating that cetotheriid mysticetes were adapted to feed upon fish as opposed to soft bodied planktonic crustaceans (e.g. krill). A few minor problems exist with this study - such as the fact that the gut contents consist of a single individual - which is not a problem for the gut contents of a large macrophagous predator like a mosasaur, but for a filter feeder that would consume thousands of fish this size a day, it makes you wonder if it's an example of accidental ingestion. Another issue is that the taphonomically informative skeleton was left in the field (I suspect owing to a storage problem at the host museum). Regardless, it's a solid advance and I was pleased to see it published. Truth be told, I wondered when fossil odontocetes and mysticetes would be found with gut contents - and I always assumed they would be discovered in the Pisco Formation of all places. It's nice when predictions are verified!
 




Modern true porpoises (Phocoenidae) are amongst the smallest of all cetaceans, and few surpass 2.5 meters in length; they share a common ancestry with oceanic dolphins (Delphinidae) and white whales (Monodontidae) sometime during the middle or late Miocene, perhaps arising from the "kentriodontid" dolphins. The sheer majority of fossil porpoises are from the north Pacific with a few important specimens from the west coast of South America, a possible periotic from New Zealand, and an extinct genus Septemtriocetus from Belgium. In contrast, phocoenids are currently nearly worldwide in distribution (within subtropical/temperate waters, anyway). This study reports a second porpoise from the North Sea, Brabocetus gigaseorum, based on a partial braincase from the early Pliocene Kattendijk Formation of Belgium. In many regards this genus is Phocoena-like (harbor porpoise) with a similar facial region but differs by possessing some archaic features. At first glance, I would assume that this would be one of the closest morphological matches to modern phocoenids, which typically form a crown clade without any extinct genera in cladistic analyses of porpoises, with all extinct genera of porpoises falling outside this group. However, their analysis shows Brabocetus forming a clade with Septemtriocetus, Haborophocoena, Salumiphocoena, Archaeophocoena, Miophocaena, and strangely, Semirostrum. I'm skeptical of the placement of Brabocetus, and I strongly suspect that the Phocoenidae is taxonomically oversplit - but more fossils are the only way to cure this issue and this paper is a fine contribution to porpoise evolution. Because Brabocetus and Septemtriocetus are in the eastern North Atlantic, they suggest an early Pliocene dispersal of phocoenids through the Arctic shortly after the opening of the Bering Strait - followed by a second dispersal through the arctic during the middle or late Pleistocene by extant harbor porpoise (Phocoena phocoena).






The giant sea cow Hydrodamalis gigas was discovered by the shipwrecked crew of the Svyatoy Pyotr in the Komandorsky Islands in 1741 and named the Steller's sea cow after the Russian expedition's German naturalist Georg Wilhelm Steller. Within 30 years this giant kelp-feeding sirenian was extinct; for over two centuries it was assumed that Hydrodamalis was hunted to extinction because of how easy it was to kill. Indeed, stories about this source of food circulated amongst fur traders in the Kamtchatka region, and it has always been suspected that subsistence by fur traders drove the last population of Hydrodamalis to extinction. Another hypothesis that has gained traction in recent years, but has been notoriously difficult to actually test - is the possible influence of sea otter hunting rather than direct hunting of Hydrodamalis. After all, Hydrodamalis lived pretty much from Japan to the Aleutians and down to Baja California during the late Pliocene, long before humans ever made it to the Pacific coasts; whatever snuffed out the last remaining populations of Hydrodamalis in the subarctic was perhaps a long time coming. The idea is simple and elegant: sea otters tend to keep sea urchin populations down, and in areas where sea otters have been removed from the environment by overzealous hunting, sea urchins completely consume and destroy kelp forests (within 5-8 years of sea otter extirpation). The diet of Steller's sea cow was entirely based on kelp - and the crew of Bering's expedition noted abundant sea otters in the Komandorsky Islands. Because of this relationship, sea otters are a keystone species and help maintain kelp forests. Whereas sea cows were demonstrably extinct by 1768 at Bering Island, sea otters had been extirpated in the Komandorsky Islands by 1753; in Alaska, sea urchin populations did not really "explode" until a few years after sea otters began to decline, followed by kelp forest collapse. This lag matches rather well with the earlier reported extirpation date of sea otters (1753) and the sea cows (1768). [Note that the Bering expedition discovered the sea otter as well, and within a year or so of being discovered the word got out about their luxurious fur and the sea otter fur trade began; sea otters were hunted mercilessly from west to east, with the Russians pushing the fur trade into Northern California by the early 19th century.] The authors go one step further and used population modeling and simulation of starvation to show that sea otter hunting alone, even without any direct hunting of sea cows, would have driven extinction of the doomed giant sirenian by itself.




This paper is a review of archaeocete evolution, and since it is a review paper, will only get brief treatment here. The review is intended to provide a comprehensive summary of trends in archaeocete evolution - indeed, nearly 2/3 of the paper consists of a family-by-family discussion of what we know about each archaeocete "family". While the reference list is quite good in terms of inclusion regarding papers published prior to 2005, many more recent advances such as the discovery of good postcrania for North American protocetids (Natchitochia, Georgiacetus), protocetids with excellent skeletons and fetuses (Maiacetus), and also fails to include any citations of recent excellent work produced by Julia Fahlke and colleagues. The paper casts doubt on the hippo-whale link, consistently claiming that the cetacean-mesonychid hypothesis is always identified when molecular data is excluded - which may have a grain of truth, but the most comprehensive analysis to date by Michelle Spaulding et al. (2009: PLoS One) showed that tree topology of the artiodactyls (and thus cetaceans and mesonychids) is very sensitive towards which taxa are included/excluded from the matrix, which seems to be a bigger problem than just molecules v. morphology/combined analyses. Ultimately, this paper doesn't really present any new ideas, and since we've already had on average one review paper on archaeocete evolution ever two years, I'm not sure why we needed another - particularly considering that many important studies of archaeocete evolution have been omitted in this study. The authors could have just consulted my 2012, 2013, and 2014 marine mammal paleontology summary posts!
 






Marine vertebrate paleontologists studying fossils from the west coast of North America are well-acquainted with concretions - extremely hard carbonate (and occasionally phosphatic) nodules that form around marine vertebrate remains. Concretions are much harder than surrounding rock, and will often erode out of cliffs but keep the entombed fossil in good condition as it slowly worries away by wave action. Concretions are an absolute pain to work with, as they often require mechanical preparation with pneumatic tools or chemical preparation with acids to remove the bones. Fossil marine vertebrates in the Pisco Formation of Peru are often entombed within dolomite concretions, and may be linked with the excellent preservation of fossils. This new study is yet another excellent contribution towards the geological context of spectacular marine vertebrate assemblages from the Pisco Formation, and reports new data from the field and petrographic results to investigate the formative processes involved in Pisco concretions. These authors note that a higher proportion of mysticete (baleen whale) fossils are associated with concretions, suggesting that they are more likely to form with larger carcasses. Specimens in concretions are also more likely to be complete and articulated. Based on the distribution of dolomitic matrix, soft tissues must have already been decayed prior to formation of dolomitic cement, and bones must have been at least partially buried. In some cases, dolomitic matrix forms only within the bones - an ideal situation, as it  has prevented burial compaction and deformation of the bones. Dolomite is commonly assumed to be a diagenetic or metamorphic "sequel" to original limestone - but in these cases, it appears that dolomite was directly precipitated without a limestone precursor (a similar process affects Purisima Formation vertebrate-bearing concretions at Point Reyes National Sea Shore). This study proposes that dolomite was precipitated as a response to the decay of organic matter of the whale after skeletonization and burial, thereby forming nodules and infilling bones with cement that contribute to their preservation and recovery. An earlier study by young earth creationists claims that excellent vertebrate preservation in the Pisco Formation is caused by extremely fast sedimentation (these rates, by the way, they use in the non-scientific literature and extrapolate to the entire Pisco basin, claiming that the entirety of the strata would have been deposited in 20,000 years rather than 20 million, supposedly meaning that scientific dating methods do not work). Instead of requiring bizarre claims about ultra-fast (shall we say, biblical?) sedimentation rates, this new study finds a far more logical solution: that the organic matter whales possess at the time of death and burial contributes to dolomitic cementation and ultimately their preservation.





In 2013 Mark Uhen published a review of basilosaurids from North America and noted that the classic species Zygorhiza kochii, the smallest basilosaurid from the Eocene of the gulf coast, is based on a poorly preserved braincase that does not preserve any autapomorphies and is therefore non diagnostic, thereby making Zygorhiza kochii a non-diagnosable taxon. To remedy this Uhen submitted a proposal to the ICZN requesting that well known specimen USNM 11962 (the de facto reference specimen for the species since Kellogg described it in the 1930s) be designated as a neotype. Gingerich (alluded to above) published this comment on Uhen's proposal effectively pointing out that such actions are unwarranted under current ICZN rules for type specimens. Type specimens do not necessarily need to be "good" or diagnostic (they just ought to be). Gingerich (and see Gingerich, above) insists that the Jackson Group cetacean assemblage includes only three basilosaurids: a small species (Zygorhiza), a medium sized species (Pontogoneus brachyspondylus, aka Cynthiacetus maxwelli), and a large species (Basilosaurus cetoides). Under this paradigm, all basilosaurid material smaller than Pontogoneus/Cynthiacetus belongs to Zygorhiza anyway, and designating a neotype wouldn't really solve any pressing issue. This debate highlights an interesting philosophical rift within paleontology: what good are shitty type specimens? I see pros and cons on each side, but at the end of the day, identification of new material should be based on more than just size alone, meaning that having anatomically informative type specimens is important towards reliably making comparisons and identifications of new material in a semi-repeatable, non-willy nilly approach.





The toothy basilosaurids are easily some of the most iconic of all cetaceans owing to their fearsome jaws and large size, and are also the largest and most completely known of all the archaeocetes. Many are quite large (Basilosaurus, Basilotritus) but others are smaller - including Dorudon and Zygorhiza. The former is easily the most well-known archaeocete (South Carolina, Egypt) and the latter is well-known from the southeastern USA - but this paper was more or less the first treatment of Zygorhiza since Remington Kellogg's seminal masterpiece "Review of the Archaeoceti" published 80 years ago, a fact which Gingerich laments. There are many new specimens of Zygorhiza now, but for some strange reason very few of them have been published upon (the same can be said for Basilosaurus cetoides, in my opinion). A "new" specimen (collected in a large plaster jacket in the 1960s, and shopped around on loan for forty years until Gingerich took it to Michigan to get prepped out) includes part of a skull and much of the vertebral column, allowing reevaluation of vertebral numbers and morphology. Further, the skull was scanned to produce a digital endocast, which was compared with a digital endocast for a separate specimen published a decade ago by Lori Marino and others. Relative brain size is on the small size for a terrestrial mammal of comparable body size, but intermediate between mysticetes and odontocetes. Lastly, Gingerich discusses the archaeocete fauna of the Eocene of the Gulf Coast, remarking that there is always one small basilosaurid (Zygorhiza kochii), one large basilosaurid (Basilosaurus cetoides), and a medium size basilosaurid. Pontogeneus priscus was originally based on an isolated, medium sized cervical vertebra, in the 19th century when standards for paleocetological holotypes were not yet "evolved". This taxon was later declared a nomen nudum by Mark Uhen, who named the new genus and species Cynthiacetus maxwelli based on a partial skeleton including a nearly complete (but incompletely figured) skull. Gingerich interpreted Cynthiacetus as a junior synonym of Pontogeneus, and discussed what we can and should do with ICZN rules for types. In other words: a type need not survive to the present day (see below) or even be diagnostic, so we can get away with using shitty Georgian or Victorian era types. My opinion: if there's no preserved autapomorphic features (e.g. the fossil is a cetacean vertebra), it should be declared a nomen dubium as it is impossible to unambiguously diagnose the taxon. A name, then, is only as good as its type. We'll see how this one pans out.




A lot of ideas are floating around in this paper, which reports a new archaeocete fauna from the middle Eocene Aridal Formation of Morocco. Six archaeocetes are present, including three protocetids (protocetids are the geochronologically latest archaeocetes which retain hindlimbs - Maiacetus, Rodhocetus, Georgiacetus). The protocetids include unidentified small and medium sized taxa based on fragmentary postcranial bones, and teeth and postcrania of the large protocetid Pappocetus lugardi. Pappocetus is of particular note because it was originally reported from similarly aged deposits in Nigeria, and this record extends the range of this early whale across most of west Africa. The basilosaurids tell a much more interesting story, and include the small bodied new species Chrysocetus fouadassii, the somewhat larger new species Platyosphys aithai, and the large basilosaurid Eocetus schweinfurthi. The new species of Chrysocetus is notable since the type species, Chrysocetus healeyorum, was named from the Eocene of South Carolina, and is the smallest basilosaurid from the Atlantic coastal plain - and thought to be one of the earliest monophyodont cetaceans (e.g. only a single set of teeth). Most of the differences with C. healeyorum are expressed in the postcranial skeleton. I'll explain Eocetus next, since it's a bit easier: Eocetus schweinfurthi, formerly identified as a giant protocetid, is likely instead a basilosaurid according to this study. New specimens include teeth, vertebrae, and a tympanic bulla - and expand the range of Eocetus schweinfurthi from Egypt to Morocco. Lastly, a strange basilosaurid skull with abundant pachyosteosclerotic growth and large, inflated vertebrae with many small foramina and elongate transverse processes is named as Platyosphys aithai. It matches the vertebral anatomy of Platyosphys paulsonii, a poorly known archaeocete described in the late 19th century from the Eocene of Ukraine. The type of P. paulsonii is an isolated vertebra that is now lost. Platyosphys-like species have since been reported from the southeastern US (Eocetus wardii) and then Ukraine again, and named Basilotritus uheni (and the former reclassified as Basilotritus wardii). Gol'din and Zvonok (2013) declared Platyosphys to be a nomen dubium because the type specimen is lost; however, Gingerich points out that technically speaking, under the ICZN, a name is available so long as evidence towards the type actually existing has been published - so despite being lost, Brandt (1873) published beautiful illustrations of the type vertebra(e). Is the type specimen crappy? Yes, and it's possibly gone forever - but the vertebrae of Platyosphys paulsonii are very distinctive in comparison to the crappy type specimen of Pontogoneus brachyspondylus (see above) so I'm more inclined to agree with Gingerich on this case.




This new paper provides a long-needed redescription of the problematic "cetothere" Mesocetus argillarius, originally named by Flemming Roth in the late 1970s. This specimen is from the upper Miocene Gram Formation of Denmark, which historically has also yielded the Pelocetus-like baleen whale Uranocetus and poorly preserved pontoporiid dolphins. Differing from other Mesocetus (which similarly deserve modern re-treatment), the authors assign it to the new genus Tranatocetus. The skull is broadly similar with some poorly known "cetotheres" (occasionally regarded as true Cetotheriidae or "cetotheres" sensu lato) such as Mixocetus, "Aulocetus" latus, "Cetotherium" vandelli, and "Cetotherium" megalophysum,, but has a very primitive lower jaw with an enormous mandibular foramen. Cladistic analysis places these poorly known "cetotheres" including Tranatocetus as sister to the Balaenopteroidea (gray whales + rorquals), and the authors erect a new family, Tranatocetidae, based on derived features of the tympanic bulla and some other features of the braincase. "Cetotheres" in this study have been split into the Cetotheriidae, sister to the Neobalaenidae similar to the provocative hypothesis of Fordyce and Marx (2013), on the neobalaenid/cetotheriid "stem", within the Tranatocetidae, and on the tranatocetid + balaenopteroid "stem". Further testing of this interesting hypothesis of mysticete relationships will require redescription and reanalysis of poorly known "cetotheres" like "Cetotherium" megalophysum and "Cetotherium" vandelli.




Bone histology is a useful way to study how vertebrates grow. In the case of many terrestrial vertebrates, bone growth can even be studied at a level where annual growth lines may be counted like tree rings - many friends of mine who were in graduate school when Sarah and I were at Montana State involved this sort of study - Holly Woodward, Julie Reizner, Alida Bailleul, John Scannella, and even our friends Liz Freedman-Fowler and Laura Wilson-Brantley (taphonomists originally!) couldn't avoid histology. Marine vertebrates on the other hand do not preserve these sorts of growth lines quite so well (though counting growth lines in marine mammal teeth is a commonly used method for modern species). However, various marine tetrapods have adapted their terrestrial skeletons to problems of swimming and buoyancy in various ways, and many possess peculiar patterns of dense bone growth, hypothesized by some to be bone ballast. Histology is destructive, and this study sought to sample many postcranial bones of archaeocete whales including precious vestigial hindlimbs - so high resolution CT imaging was used instead to study changes in bone microstructure across the terrestrial-marine transition in early whales - remingtonocetids, protocetids, and basilosaurids. All exhibited bone mass increase in their ribs, but the vertebral column consists chiefly of spongy bone. The humerus of protocetids retains thick cortex (an adaptation for locomotion on land or paddling), but within basilosaurids the humerus becomes more strongly spongy and porous - indicating a transition from forelimb paddling to use of the foreflipper as a simple hydrofoil like modern cetaceans. On the contrary, the femur becomes very dense - even in the vestigial hindlimb of basilosaurids, which remains unexplained. The pattern of bone mass increase in Basilosaurus was originally interpreted to be an adaptation for control of "trim" - orientation of the vertebra column with respect to the horizontal plane (e.g. "pitch" in an aircraft) - sampling additional bones from the skeleton now rules out this hypothesis, but the authors indicate that no other existing explanation is sufficient. Regardless, patterns of bone microstructure are consistent with remingtonocetids and protocetids being shallow diving, semiaquatic swimmers with a limited capability of terrestrial locomotion like pinnipeds and sea otters, whereas basilosaurids are broadly comparable with modern cetaceans, consistent with interpretations of basilosaurids being the earliest oceangoing (pelagic) cetaceans. This study also showed that microstructure can change dramatically along the long axis of a rib or other bone, demonstrating the importance of taking numerous sections.




How did the skull of aquatic carnivores evolve after making the land to sea transition? Was it a passive process, or did pinnipeds undergo an adaptive radiation? This new study by Katrina Jones and others investigates this by using 3D morphometrics of modern and extinct terrestrial "fissiped" and pinniped carnivorans within a phylogenetic context. Several fossil pinnipeds were included such as Enaliarctos emlongi, Allodesmus, Pontolis, Piscophoca, and Acrophoca. Overall pinnipeds exhibit a greater variation in skull shape (disparity) than terrestrial carnivores. However, there is no increase in evolutionary rate at the base of the pinniped tree, indicating passive evolution of skull shape (e.g. "Brownian motion") and indicating that an adaptive radiation model does not fit very well. Within later groups of pinnipeds evolutionary rates sped up, perhaps associated with ecological specialization (e.g. walruses and suction feeding). In the context of the late Oligocene-early Miocene pinniped fossil record, this does make sense as nearly all pre-middle Miocene pinnipeds are enaliarctines that look fairly similar and share similar body sizes despite belonging to different lineages (Enaliarctos, Pteronarctos, Pinnarctidion, Prototaria, Proneotherium) - Desmatophoca being a notable exception.




This article is entirely in Japanese, and while it does have an English abstract and good photos, the fossil described is incomplete and the abstract short – so my summary will be as well! This specimen is from the middle Miocene and consists of a partial posterior part of a mandible. This specimen has a small, laterally projecting coronoid process, an enormous and anteriorly expanded mandibular foramen a tiny mandibular condyle, and a ventrally deflected angular process. These features are all consistent with this specimen belonging to a “Kelloggithere” - an informal name for “cetotheres” sensu lato like Parietobalaena, Pelocetus, and Diorocetus. This group is well-represented by a large collection of terribly understood fossils. Other specimens with a similar angular process have also been reported from Japan, but belong to an unknown mysticete – a similar mandible is present in Mauicetus parki from New Zealand.




This article is also entirely in Japanese with the exception of the abstract, so my summary is going to be brief! It does have an English abstract and good figures, so I'll communicate what I can. Japan has an excellent fossil record of cetaceans including my favorite group - baleen whales. However, many of these are not yet described, and many late Miocene and Pliocene mysticetes from Japan have been under study for years without any resulting publications, a frustrating situation for some. This new paper reports a balaenopterid whale, more commonly known as a rorqual (humpbacks, minke, fin, blue whales are all rorquals), from upper Miocene rocks of Miyako Island which is located pretty far south and relatively close to Taiwan. This specimen consists of a partial skull lacking a rostrum, is somewhat fractured, and has some adhering concretionary matrix. The specimen cannot be identified to any existing balaenopterid genus owing to its braincase morphology - and is too incomplete to designate as a type specimen, so the authors simply identify it to the family level. In my opinion, this whale is most similar to the archaic taxon Protororqualus cuvieri, but it's anybody's guess at this point; more preparation would be instructive, as the critical earbones are still in situ. A tantalizing find, and according to Felix Marx more research is being done on this specimen.




Many of the world's oldest well-preserved phocid seals (true, or earless seals) - and many of the earlier reports of fossil true seals in general - come from marine deposits of Paratethys, a former sea that occupied a foreland basin to the north of the Tethys sea (the Black, Caspian, and Aral seas are the remaining deep pockets of this former sea). Paratethyan deposits stretch from Austria to Kazakhstan; biostratigraphy is often rudimentary, but marine mammal fossils are plentiful. One of the earliest phocids known by a good skull was named Devinophoca claytoni in 2002; this early seal has features of both the Monachinae (southern seals) and the Phocinae (northern seals), potentially indicating ancestral relationships. This new article by Irina Koretsky and Sulman Rahmat names a second species of Devinophoca based on another well preserved skull, isolated teeth, and mandibles. The skull is similarly generalized, but has a monachine-like number of incisors; the new mandible differs from monachines and is very similar to the gracile mandible of the early phocine Leptophoca. Interestingly, Devinophoca inhabited subtropical waters with abundant corals, and was likely a shallow diver.




Unlike the above mentioned Devinophoca, the sheer majority of the phocid (true seal) fossil record is constituted by disarticulated, non-associated postcranial bones. This problem has plagued pinniped paleontology in general since J.P. Van Beneden began studying Mio-Pliocene true seals from North Sea deposits in Belgium and the Netherlands, and named a bunch of problematic species & genera based on disparate material, many of which have been suspected to be chimaeric assemblages of postcrania. With the exception of European & Paratethyan taxa based on crania (Devinophoca, Praepusa, and Pliophoca - see Berta et al., above) and New World taxa based on associated skeletons (Monotherium wymani, Leptophoca, Piscophoca, Acrophoca, Hadrokirus, and now Australophoca - see below) it's unclear how many of these postcranial taxa are real. How much do pinniped postcrania vary within a population, or how similar are they between taxa? Sexual dimorphism is also a huge problem. These are valid but also very basic questions that have not really been addressed, yet the study of fossil phocids has been plagued by these problems for over a century while students of true seal anatomy continue to ignore them. This new study reports several isolated postcranial elements from the including two humeri and a sacrum - one complete female humerus, and a partial male humerus. These remains do reflect an extraordinarily tiny seal - smaller even than the newly described Australophoca (see Valenzuela-Toro et al., below). The authors make favorable comparison to postcrania of the Miocene Paratethyan seal Praepusa, and base the new species Praepusa boeska on the complete female humerus and refer the other bones to it. Dating of the locality is poor - late Miocene to "mid" Pliocene, 11.5-3.5 Ma. The authors discuss the fossil record of Praepusa, and point out that the earliest fossils (P. vindobonensis) originate from the middle to late Miocene (16.5-11.2 Ma) of Kazakhstan and Austria, the somewhat younger species P. pannonica is from the late Miocene (12.3-11.2 Ma) of Moldova and Hungary, P. magyaricus is similarly from the late Miocene (13.6-12.3 Ma) of Austria, and the new North Sea species, P. boeska, is from the late Miocene-Pliocene of the eastern North Atlantic (11.6-3.2 Ma). This does paint a rather interesting picture of seal dispersal out of the Paratethys westward into the north Atlantic. Future discoveries of cranial material and associated skeletons are needed to assess whether or not Praepusa is monophyletic.
 






The early Miocene is an intimidating time for students of toothed whale evolution – quite a bit is going on, and there are a zillion different types of long-snouted dolphins living alongside the early ancestors of modern groups (some of the earliest sperm whales, the earliest possible delphinoids, purported early beaked whales). Some of these speciose families of longirostrine dolphins either originating or diversifying during the early Miocene include the Eurhinodelphinidae, Squalodelphinidae, Platanistidae, Allodelphinidae, Eoplatanistidae, and the “Dalpiazinidae”. Early Miocene odontocetes suffer from several problems – many are known from good skulls but not well-prepared or figured earbones; some taxa are almost certainly oversplit, and there is likely an overemphasis on the definition of family level taxa, some of which are likely para- or polyphyletic. Lastly, because of these issues, the phylogenetic relationships of these problematic dolphins are poorly known – and these reasons are why the early Miocene scares the shit out of me. This study daringly reports a long snouted dolphin, Chilcacetus cavirhinus from the lower Miocene Chilcatay Formation of Peru. This dolphin has a long snout and a homodont dentition – in other words, the teeth are all identical in shape and all are single rooted. Chilcacetus uniquely has a deep cavity between the nasal bones and the mesethmoid. It is similar to the giant dolphin Macrodelphinus kelloggi from the lower Miocene Jewett Sand of California, which has been classified in the past as a giant eurhinodelphinid. However, Chilcacetus – which has part of a mandible as opposed to the fragmentary Macrodelphinus type specimens – has an unfused mandibular symphysis, unlike all eurhinodelphinids. The taxonomically informative earbones were unfortunately lost between collection and publication, but somewhat detailed line drawings were prepared before they were lost. Other features preclude assignment to any other odontocete family. Cladistic analysis of Chilcacetus and other odontocetes actually supports a clade including Chilcacetus, Macrodelphinus, Argyrocetus from Argentina, and “Argyrocetus” (two species from California) – which could be named as a new family. The authors stop short of this, highlighting low statistical support for the grouping and lack of unambiguous synapomorphies. However, the grouping does consist of mostly eastern North Pacific and South American species; anatomical features supporting this clade are mostly primitive features that set them apart from later diverging odontocetes. As per usual, more fossils and more character evidence is needed to make sense of these challenging taxa.





Gut contents is widely reported for fossil skeletons of marine reptiles – skeletal remains of a larger animal's last meal. Mosasaurs, plesiosaurs, ichthyosaurs, sharks, and large fish are all known with well-preserved gut contents. For some reason, however, gut contents of marine mammals is much more rare. Ironically, little is known about the feeding behavior of modern marine mammals since it is difficult to directly observe them out at sea – so much of our knowledge of the diet of modern marine mammals is recorded from necropsies and gut contents. The difference is that in modern specimens, soft bodied prey can be observed – but in the rock record, only prey items with hard tissues become preserved, with some rare exceptions (e.g. cephalopod beaks, which are keratinous). Prior to this study the only marine mammal with gut contents was the Miocene seal Kawas from Argentina. I have wondered when the first fossil cetacean with gut contents would be discovered, and figured that if it were to be discovered anywhere it would be from the Pisco Formation of Peru. My gut instinct (no pun intended) was vindicated this year with the discovery of a Messapicetus specimen with abundant sardine skeletons preserved around it. However, it is unclear what exactly was collected as opposed to left in the field (see Collareta et al., above). Regardless of these issues, this study indicates that an early beaked whale (Ziphiidae) had a gut full of shallow water fish (Sardinops) when it died. Modern beaked whales are suction feeding, deep diving squid specialists. Assuming that this individual died after consuming a typical meal for its species, this fossil may indicate that Messapicetus was not a deep diving squid specialist, perhaps indicating that deep diving “teuthivory” is a more recent feature of beaked whales. Surely, the Pisco Formation will produce more treasures that will expand our knowledge of ancient food webs.




This new study is the product of Felix Marx's Ph.D. thesis at the University of Otago, and I was fortunate to see quite a bit of this long before it came out. The core of this study is a new phylogenetic analysis of baleen whales (Mysticeti) and is a successor to an earlier cladistic matrix produced during Marx' master's program at Bristol. This new phylogenetic analysis includes the most number of baleen whales (though with 3/4 the character evidence as the largest published analysis). These authors again recovered an aetiocetid-mammalodontid toothed mysticete clade, a monophyletic Cetotheriidae including the pygmy right whale, possible resolution amongst "kelloggitheres", and gray whales (Eschrichtiidae) deeply nested within the rorquals (Balaenopteridae). This new analysis is essentially a semi-comprehensive study of mysticete evolution, and also used the morphological dataset to study disparity (anatomical diversity) through time. Disparity peaked during the Oligocene and plateaued during the Neogene, whereas taxonomic diversity was highest during the middle and late Miocene and dropped off during the Plio-Pleistocene (perhaps an artifact of the rarity of published accounts of Pliocene mysticetes). Alternatively, evolutionary rates were highest during the Oligocene and flatlined thereafter - suggesting early settling into "modern" filter feeding niches. Mysticete diversity seems to drop as soon as modern gigantism appears, suggesting an influence of Plio-Pleistocene glacial influence on baleen whale evolution.
  


Marx, F.G., C.H. Tsai, and R.E. Fordyce. 2015. A new early Oligocene toothed ‘baleen’ whale (Mysticeti: Aetiocetidae) from western North America: one of the oldest and the smallest. Royal Society Open Science2:150476.

Most modern baleen whales are known best for their massive size – the smallest modern baleen whales – the pygmy right whale Caperea marginata and the dwarf form of the minke whale Balaenoptera acutorostrata – are still 5-6 meters long. Many of the earliest baleen whales which retained teeth – aka toothed mysticetes – were on average quite a bit smaller. One family in particular, the Aetiocetidae – perhaps the best understood of all toothed mysticetes next to the well-published mammalodontids – were comparable in size to modern small-bodied dolphins. Aetiocetus & Morawanacetus are in the size range of bottlenose dolphins, whereas Chonecetus is approximately the size of a harbour porpoise. Aetiocetids are hypothesized to be the earliest baleen-bearing cetaceans, with teeth and palatal vascularization reported in Aetiocetus weltoni. However, their earbones – an anatomically informative part of the skull – are very poorly known, and their teeth are virtually unknown aside from two species of Aetiocetus and a single pair of molars in Morawanacetus, making inferences about their diet and feeding adaptations difficult. A new specimen from the Makah Formation of the Olympic Peninsula in Washington is named as Fucaia buelli – the species name in honor of the talented and prolific illustrator Carl Buell (a well deserved honor, and I think this was a very nice touch by the authors), with the genus name referring to the type locality along the southern shore of the Strait of Juan de Fuca. This new aetiocetid preserves a partial skull, earbones, some teeth, many vertebrae, and a scapula – it is characterized by small size, large eye sockets (orbits), primitive archaeocete-like teeth, delicate hyoid bones. Cladistic analysis allies this species with Chonecetus goedertorum, which the authors reassign to the new genus as Fucaia goedertorum. Though most of the feeding apparatus is gone, the teeth are heterodont – caniniform anterior teeth and multicuspate, subtriangular cheek teeth are present, similar to archaeocetes – and they have wear facets, indicative of some degree of occlusion. Tooth morphology and wear suggests that Fucaia was a raptorial feeder, using its dentition to catch fish, contrasting with the comparably tiny teeth of Aetiocetus (Aetiocetus is approximately double the size of Fucaia, but has teeth that are much smaller) – the latter was likely an early filter feeder owing to its tiny teeth, rotate-able mandible, and possible presence of baleen. The authors suggest that aetiocetids (and mammalodontids) represent an intermediate stage of feeding adaptation involving raptorial suction feeding, which led to suction-based filter feeding, and eventually “pure” filter feeding.

  


Desmostylians are known only from the late Oligocene and Miocene of the North Pacific, ranging from Japan north to Alaska (see Chiba et al., above) and south to California and Baja California. Paleoparadoxia has of course now been split out into three genera, including Archaeoparadoxia and Neoparadoxia. Prior to this, Paleoparadoxia was the longest ranging desmostylian, ranging in age from about 23-9 Ma or so. Since being taxonomically split, the situation is a bit different - and this study seeks to refine the geochronologic range of true Paleoparadoxia, as the splitting by Barnes (2013) mostly affected fossils from the Miocene of California, but left the situation unclear regarding other paleoparadoxiines. This study reviews the fossil record of "true" Paleoparadoxia from Japan and reports a partial forelimb from the earliest Miocene. Several records of Paleoparadoxia from Japan are associated with cold temperate mollusk assemblages while others are associated with warm temperate mollusks - indicating flexibility towards water temperature (i.e. within the lineage). The new specimen reported from Hokkaido is the geochronologically oldest record of Paleoparadoxia, determined to be earliest Miocene (23.8-20.6 Ma) by the authors. Inuzuka previously hypothesized that Paleoparadoxia from the early Miocene of Japan may have evolved directly from Archaeoparadoxia weltoni. However, the discovery of a more derived true Paleoparadoxia from temporally equivalent rocks in Japan indicate that at least two paleoparadoxiines were living during the earliest Miocene, complicating the picture somewhat.




Modern river dolphins were formerly thought to constitute a single group, the Platanistoidea - until it became obvious in the 1980s from skeletal anatomy and fossils that each modern river dolphin (Inia, Lipotes, Platanista, Pontoporia) likely had separate origins, later confirmed by molecular work in the early 2000s. Two of these may in fact be somewhat closely related - the Amazon river dolphins, Inia, and the La Plata river dolphin, aka Franciscana, Pontoporia (which is actually mostly marine). The recently extinct Yangtze river dolphin Lipotes is now thought to be closely related to Parapontoporia from California (see Boessenecker and Poust, above), but has no other near relatives in the fossil record. The origins of the totally bizarre Ganges/Indus river dolphins Platanista have been more contentious, possibly involving the Squalodelphinidae, Squalodontidae, and even the Oligocene Waipatiidae. The evolution of the South American river dolphins is less controversial, and many fossils have been reasonably identified as extinct marine (and freshwater) of Inia (Ischyorhynchus, Saurocetes, Goniodelphis, Meherrinia) and Pontoporia (Brachydelphis, Pliopontos, Protophocoena, Auroracetus, Stenasodelphis). A new fossil discovered by J. Velez-Juarbe and others during the Panama Canal Project (PCP-PIRE) from the late Miocene of Panama includes a large, well-preserved skull and mandible with associated teeth, scapula, and carpal elements and is named in this study as Isthminia panamensis. It is large (nearly 3 meters in length based on skull size) with relatively robust teeth and an elongate, narrow rostrum like extant Inia. Unfortunately, anatomically informative tympanoperiotics are unknown. Because Isthminia was recovered from marine sediments, the authors interpret it to be a marine rather than a freshwater iniid. However, it is important to note that terrestrial animals frequently become entombed in marine sediments (likely carried out to sea during floods) and in general tetrapods are terrible paleodepth indicators. Regardless, the cladistic analysis and inferred environmental preference of modern and extinct inioids indicates that in South America, a patchwork pattern of freshwater invasion of river basins occurred, paralleling the recently reported occurrence of a platanistid from the Peruvian Amazon (Miocene; Bianucci et al., 2013) and the possible freshwater invasion of California's San Joaquin Valley by Parapontoporia (Boessenecker and Poust 2015, see above) - indicating significant adaptability among modern and extinct river dolphins and their marine relatives. 




The early evolution of baleen whales is now revealed by a series of nice transitional fossils including many well-preserved skulls showing a gradual evolution of baleen whale "features" from the ancient basilosaurid skeletal plan. However, most early fossils of odontocetes - toothed whales - are already highly derived, quite obviously being early dolphins with facial features consistent with echolocation and already well-telescoped skulls (telescoping is the posterior migration of rostral bones over the braincase, thought to "track" the posterior migration of the bony nares). Some putative latest Eocene odontocetes are reported from the Olympic Peninsula of Washington, but they are not yet really published (a short conference paper exists - not just an abstract - but there are no figures, nothing is named, and a longer paper is promised). A new fossil dolphin from the Ashley Formation here in Charleston, appropriately named in this paper as Ashleycetus planicapitis, is noted for its rather plesiomorphic (="primitive morphology") skull including limited telescoping, anteriorly positioned bony nares, and maxillae that only cover part of the frontal. The top of the skull is remarkably flat when viewed from the side, hence the species name. With the exception of the enigmatic dolphin Archaeodelphis (the locality of which is unknown, but thought by some to be from the Oligocene Ashley or Tiger Leap Formation of the Charleston area), Ashleycetus is the most plesiomorphic known odontocete - and given that much more derived dolphins are known from the Oligocene Ashley Formation, it's already a relict species. Given what we know of the Oligocene cetacean record, I would expect Ashleycetus-like odontocetes to show up in much earlier rocks, perhaps somewhat more archaic forms even in the late Eocene. This paper is absolutely overflowing with ideas and good observations, and given my new job working with early odontocetes here in SC - I've been finding myself re-reading parts of this paper over and over. This paper also provides some new photographs, observations, and interpretations of Xenorophus sloani (another Oligocene dolphin from the Ashley Formation of Charleston) and Mirocetus riabinini, a weird odontocete from the Oligocene of Azerbaijan originally mistaken for a toothed baleen whale (an assumption or cognitive bias which I would wager was originally based on its size). Students of early odontocete evolution will want to read this paper very carefully. Lastly, as an aside, an interesting talk at SVP by my colleague Jorge Velez-Juarbe (LACM) included a cladistic analysis that recovered Ashleycetus as a basal member of the Simocetidae - a group of Agorophius-like dolphins with downturned snouts.
 



This is another review article, so this will be brief. Most of this review is concerned with the ecology and evolution of the invertebrate fauna inhabiting modern whale falls - which, for the uninitiated, are whale carcasses that have sunk down to the deep sea floor and host a very distinctive fauna of marine invertebrates also seen at deep see vents and methane seeps. Occasionally fossil cetaceans have been recovered with trace fossils or associated/attached body fossils of these deep sea specialists, such as vesicomyid clams and the bone eating worm Osedax (which doesn't have a mineralized skeleton, but produces distinctive borings in whale bones which do preserve). This summary concludes that most elements of modern whale fall communities had their origins during the Oligocene, corresponding to the diversification of the Neoceti - one third of all extant genera of cold seep mollusks appear during the late Eocene and early Oligocene, tightly corresponding to the diversification and worldwide dispersal of Pelagiceti (Neoceti + Basilosauridae). These authors suggest that more research into the evolution of bone lipids (the principal source of nutrients for many whale fall specialist invertebrates) within extinct cetaceans should be conducted - which may perhaps be inferred from postcranial bone histology. Lastly, modern evidence of the "reef stage" - the fourth stage in the evolution of a single whale fall (after the mobile scavenger, enrichment-opportunist, and sulfophilic stages) has been criticized by other whale fall biologists, yet has support from fossils. This stage was hypothesized to exist as a period after which the nutrients have been completely removed from the bone, but because the bones still physically extend above the seafloor sessile filter feeding invertebrates will colonize the bone to take advantage of a higher current. Many examples of barnacles, serpulid worms, bryozoans, and other sessile filter feeders are known from marine vertebrate skeletons preserved in deep marine settings.





Basilosaurus is known from two species from eastern North America (B. cetoides) and northern Africa (B. isis) and represents the largest basilosaurid archaeocetes known - giant serpentine whales with quasi-vestigial hindlimbs that lived during the late Eocene (a third possible species is debated but has been reported from Pakistan - B. drazindai). All basilosaurids are characterized by fearsome dentitions with caniniform anterior teeth and large, triangular, cuspate shearing cheek teeth - and like most archaeocetes, have tiny braincases with enormous jaw muscle attachments. Smaller archaeocetes from the same deposits as B. isis, including several juvenile skulls of the small basilosaurid Dorudon atrox, have been found with large tooth punctures, reasonably hypothesized by Julia Fahlke to be tooth punctures from B. isis. Does Basilosaurus have sufficient bite force to cause bite marks like this? What is the bite force of an archaeocete? We can't go out and put a force gauge into the mouth of an extinct organism - so computer modeling, specifically finite element modeling -  provides a means by which to estimate bite force. I won't go into how FEM modeling works, principally because I am not mentally equipped to do so - but it can be done using CT data or, as in this case, a 3D surface scan of a 3D object. Using high resolution CT data permits density/strength values to be placed onto tiny 3D 'cells' (voxels: aka 3D pixels) with the density derived directly from the CT scan. Another method is to use a surface scan and arbitrarily assign bone wall thickness (or treat it as a solid) and uniform bone density/strength within. When scaled to the same size, FEM indicates that Basilosaurus had comparable bite forces with giant predatory pliosaurs (e.g. Pliosaurus kevani). Although lesser in magnitude than the highest bite forces measured and estimated for large crocodylians and dinosaurs, bite forces predicted (16,400 newtons) at the upper third premolar (P3) of Basilosaurus exceed those of any other mammal and additionally exceed predictions of force as expected from its relatively narrow skull. Notably, Basilosaurus was capable of comparably higher bite force at the tip of its snout than crocodylians. Bite force is indeed consistent with indenting and breaking bones, and feeding behavior likely consisted of catching prey with the anterior teeth and mastication (or should we say in this case, "chopping") of prey items with the cheekteeth. 




This paper utilizes newly recovered molecular data from the extinct Steller's sea cow (see Estes et al., above) to run a comprehensive phylogenetic analysis - combined with morphological data - of modern and extinct sirenians. Much of this paper is concerned with new molecular results - which are interesting, but this post is focusing on paleontological advances so I'll focus on those. The second sentence of the abstract goes like this: "The phylogenetic affinities of [Hydrodamalis gigas] to other members of this clade, living and extinct, are uncertain based on previous morphological and molecular studies." This raised huge red flags for me because from everything I had read by two of the foremost experts in the world on sirenian evolution and anatomy, Daryl Domning and Jorge Velez-Juarbe - had indicated that Hydrodamalis is closely related to the southwestern Pacific Dugong dugon, and that giant hydrodamaline sea cows evolved in situ within the north Pacific during the late Neogene, giving rise to Hydrodamalis by the late Miocene/early Pliocene - all of this appeared non-controversial. The paper of course reports similar results, and both Daryl and Jorge are coauthors - upon further reading, other researchers have produced some rather odd results with the west Indian manatee coming out as more closely related to Hydrodamalis - which doesn't make sense for a number of reasons, such as the shared presence of tail flukes. The article also provides a brief but handy summary of macroevolutionary trends in sirenian evolution.

  

The incompletely preserved dolphin Prosqualodon marplesi was named in the 1960's from the upper Oligocene-lower Miocene Otekaike Limestone of New Zealand, originally placed in the squalodontid genus Prosqualodon. R.E. Fordyce recognized how dissimilar it was to Prosqualodon, and placed it in the squalodelphinid genus Notocetus instead when he described the other NZ dolphin Waipatia maerewhenua. Last year, my labmate Yoshi Tanaka published a reevaluation of "P." marplesi and assigned it to the new genus Otekaikea - and surprisingly recovered this specimen in a cladistic analysis as a sister taxon to Waipatia, and reclassified Otekaikea marplesi as a waipatiid. In this new paper, Tanaka and Fordyce describe a second species, Otekaikea huata, based on a much more complete specimen. Otekaikea huata has a similar braincase and earbones, differing in only a few subtle ways obvious only to students of whale anatomy too nuanced to repeat here. However, the relatively complete holotype specimen of O. huata exhibits many notable features that are interesting from a functional perspective. The rostrum is very elongate, and the teeth are nearly homodont posteriorly, with simple crowns and single roots - and transition anteriorly into tusklike apical teeth. The anteriormost tooth is huge, about 4-5 inches long, and straight - the tusk would have been procumbent, and probably not functioning for biting prey. The facial region is strongly dish-shaped, indicating the presence of a melon and associated facial muscles involved in sound production - clearly indicating that Otekaikea huata used echolocation. Hearing was specialized like many modern odontocetes, with large sinuses in place around the earbones, either for soft tissues or pneumatic sinuses - acoustically isolating the inner ear from bone-conducted sounds in the skull. Interestingly, most Oligocene odontocetes to date are known for their comparably modest rostral proportions - whereas nearly all non-squalodontid odontocetes from the early Miocene have embarrassingly elongate snouts, like Otekaikea huata (and nobody has really offered a good solution as to why). Otekaikea thus may represent the first known member of this functional group of longirostrine dolphins, giving a preview of future affairs.

  



During the late 19th and early 20th centuries a number of fragmentary but anatomically curious fossil cetaceans and penguins were discovered and named from various Oligocene marine rocks in the Waitaki Valley region of the South Island of New Zealand. Several other papers summarized above have also dealt with some of these historical specimens (Boessenecker and Fordyce 2015, Tokarahia), as well as more recently collected fossils (Boessenecker and Fordyce, 2015 – Waharoa; Tanaka and Fordyce, 2015, Otekaikea huata; Tsai and Fordyce, 2015, Horopeta). Early identifications and efforts to properly interpret these fossils were hampered by their incompleteness and lack of comparable material. The species Microcetus hectori is one of these, based on a fragmentary mandible and some isolated teeth collected from the upper Oligocene Otekaike Limestone in 1881 by notable geologist Alexander McKay. The teeth are tiny with high crowns, accessory cusps on the posterior side, and labial and lingual cingulum – in person, I call them “cute” (Yoshi Tanaka had these on the desk next to me in my office for several months while working on this chapter of his thesis). This fragmentary specimen was originally placed in the genus Microcetus based on its inferred dental similarity with Microcetus ambiguus; however, detailed observations show that the teeth differ in many regards, and at a gross level are more similar with other NZ dolphins like Waipatia. A skull in a block of sediment was also collected and discovered over 100 years later by R.E. Fordyce. Given that numerous teeth, a partial mandible, and most of a braincase were now known, the authors included it within a cladistics analysis – wherein it was allied with Waipatia maerewhenua. The authors recombined it as Waipatia hectori. This, with the reinterpretation of “Prosqualodonmarplesi as the new genus of waipatiid Otekaikea and the naming of a second species, Otekaikea huata (see above), really shakes up what was formerly thought of in terms of odontocete diversity in New Zealand as many of these seemingly different odontocetes were formerly thought to represent other odontocete families. And, there are more waipatiids to come!

 

Readers of this blog already know I have a healthy obsession with fossil walruses. Avid readers of this blog remember my series of posts on walrus evolution and already know that most extinct walruses did not have tusks, and that tusks only really characterize a few highly derived walruses from the Pliocene and younger. Most fossil walruses had skulls (and likely outward appearances in life) broadly similar to sea lions. After all, walruses are pinnipeds, and no other modern pinnipeds have tusks or such highly specialized diets - so we should expect the modern walrus to have evolved from a more generalized, fish eating ancestor. Fossils from the North Pacific - chiefly California and Japan - now illuminate the early history of walrus evolution stretching back to the early Miocene and include many early diverging, sea lion-like "imagotariine" walruses like Neotherium, Imagotaria, Prototaria, and Proneotherium. In California we have the small-bodied Neotherium in the mid Miocene (~15 Ma) and by the late Miocene (~9-10 Ma) we have the much larger Imagotaria downsi, with simpler teeth (less cusps, single rooted teeth). In 2006, Naoki Kohno reported Pseudotaria muramotoi from the early late Miocene of Japan (9.5-10 Ma), which is intermediate in terms of morphology and size between Neotherium and Imagotaria. This new paper stems from Yoshi Tanaka's master's thesis research in Japan and names a new imagotariine from the same deposits (Ichibangawa Formation, Hokkaido) that is quite a bit more complete than Pseudotaria. The type specimen of the new species Archaeodobenus akamatsui is broadly similar to Pseudotaria but differs in many features of the basicranium as well as the morphology of the cervical vertebrae. Only the left side of the skull is preserved, but hyoid apparatus and mandible as well as many teeth were recovered; additionally most of the cervical and thoracic vertebrae were recovered as well as ribs, a sternebra, scapula, and humerus. This specimen demonstrates that two similar walruses coexisted in the late Miocene of Japan, which is interesting - but multispecies walrus assemblages are already known from the Pliocene San Diego Formation (Valenictus, Dusignathus, Odobenini indet.) and mid Miocene Sharktooth Hill Bonebed (Neotherium, Pelagiarctos) of California, so this is perhaps not very surprising.



This study marks another contribution by retired fossil preparator Howell Thomas into the field of paleopathology - the study of disease in the fossil record. This study surveys osteochondrosis in modern and fossil marine mammals. Osteochondrosis has an idiopathic origin - idiopathic roughly translates to "we have no idea what exactly causes it." Osteochondrosis usually comprises damage to the articular surface of a long bone, and is thought to be caused by trauma to the joint, like extreme vertical loading of a human knee; shear loading, avulsions, and continued low-grade traumas to the same location along with some other problems can cause osteochondrosis. Trauma upsets normal cartilage growth at the joint and bone death occurs below the cartilage which manifests as a deep pit on the articular end of the bone. The authors figure and describe pits in humeri, ulnae, scapulae, and skulls of extant marine mammals including walrus, monk seals, and narwhals. Osteochondrosis is present in postcranial bones of the desmatophocid pinnipeds Allodesmus "kelloggi", Allodesmus kernensis, the "cetothere" Tiphyocetus temblorensis, a skull of the sperm whale Aulophyseter morricei, the atlas vertebra of the dolphin Zarhinocetus errabundus, and postcrania of isolated odontocetes and the desmostylian Neoparadoxia cecilialina from the Monterey Formation. This study reports the first occurrences of osteochondrosis both within modern and fossil marine mammals. It was not found in any sirenians, but instead was found only within amphibious pinnipeds and desmostylians (which could become injured when exiting/entering the water) and cetaceans (which could become injured when breaching or similar behavior).




Modern baleen whales are readily identifiable based upon their baleen as well as their enormous body size; indeed, their great mass is perhaps what best captures the imagination of the public. As alluded to above, baleen whales had rather humble beginnings – the “chonecetine” aetiocetids (e.g. Chonecetus, Fucaia) were scarcely larger than a harbor porpoise (~2 meters long). Other aetiocetids, like Aetiocetus and Morawanacetus, reported from Japan and the Pacific Northwest – are only slightly larger, perhaps approaching the size of a large bottlenose dolphin (~3-4 meters). This rather small range of body sizes contrasts with the somewhat larger (and contemporaneous) early baleen-bearing eomysticetids, which were about the size of minke whales (5-8 meters). A new aetiocetid fossil from the upper Oligocene of Hokkaido (northernmost major island of Japan) reported by Tsai and Ando consists of a squamosal and a periotic similar in morphology to Morawanacetus yabukii – but is approximately twice as large, with a body length estimate of 8 meters. This body length is in the size range of eomysticetids, and expands the range of size disparity amongst toothed mysticetes. Furthermore, because this large morawanacetine is found in the same deposits as smaller Morawanacetus yabukii, some degree of niche partitioning must have been present. Future finds preserving the feeding apparatus of the large, unnamed morawanacetine may reveal how niche partitioning occurred.




 One of the earliest fossil baleen whale earbones I ever saw photos of was a specimen collected by Ron Bushell, formerly of Eureka in northern California, who had collected it from the Plio-Pleistocene Rio Dell Formation nearby in Humboldt County. As a high school student interested in local paleontology, it boggled my mind that nobody could identify it. Years later I found out that it, and other neat specimens collected by Ron, had been kindly donated to Sierra College in Rocklin, CA. After spending a couple years during my Ph.D. staring at mysticete earbones until my eyes felt like they were going to bleed, I realized it was probably an early record of a gray whale – so I invited my labmate Cheng-Hsiu Tsai to describe it. Turns out it’s nearly identical to modern Eschrichtius robustus, so we identified it as Eschrichtius sp., cf. E. robustus. This specimen, consisting of a tympanic bulla and a compound posterior process, is more similar to modern E. robustus than a Pliocene specimen published in 2006 from Japan identified as Eschrichtius sp. As it happens, Bushell’s specimen is from the uppermost Rio Dell Formation, making it early Pleistocene (~1-2 Ma) in age – a time period nearly completely unrepresented for marine mammal fossils in the east Pacific. There is a more “primitive” unnamed genus of gray whale (Eschrichtiidae) from older Pliocene rocks in California, but no bona fide records of Eschrichtius; the Pliocene of California is probably well sampled enough to declare that Eschrichtius was not present (but at least a half dozen other mysticetes were present instead). Given the delayed occurrence of Eschrichtius in California relative to Japan, we hypothesized that the modern gray whale evolved in the western North Pacific during the Pliocene, and dispersed to the eastern North Pacific during the early Pleistocene – sometime after the Plio-Pleistocene marine mammal extinction which led to the demise of eastern Pacific walruses (Dusignathus, Valenictus), the bizarre porpoise Semirostrum, and other cetaceans. 




 The idea of ancestor-descendant relationships has pervaded paleontology since the 19th century, but with the advent of cladistics and the emphasis on phylogenetic relationships a bizarre misconception that we cannot identify ancestors and descendants in the rock record has arisen. Certainly this is an artifact caused by the fact that cladistics - the dominant method for inferring phylogenetic relationships amongst modern and extinct organisms - can only infer "relatedness" but not time. Thus, inability to interpret ancestors versus descendants is based on a limitation of our current methodological paradigm - a limitation that this new study seeks to circumvent. This study investigates the highly problematic and controversial relationships of the pygmy right whale, Caperea marginata. A very Caperea-like fossil, Miocaperea pulchra, is known from the late Miocene of Peru (and these authors suggest that it could even be recombined as Caperea pulchra, given the similarity). A well-known but underappreciated aspect of anatomy is that growth of vertebrates roughly parallels the evolutionary history - in an imperfect sense, not quite as predicted by Ernst Haeckel (ontogeny recapitulates ontogeny). Generally speaking, in many vertebrate groups, juveniles will look like ancestors - to the point where juvenile hadrosaur dinosaurs have been misinterpreted as small adults of late surviving archaic hadrosauroids. An earlier study by some Canadians and my dear friend Liz Freedman-Fowler (Hi Liz!) found that when juveniles of known hadrosaur species within different families were coded into an existing cladistic dataset, the juveniles all plotted together on the paraphyletic "stem" of the group. This concept applies to cetaceans as well. In this study, Miocaperea, adult Caperea, and juvenile Caperea were coded as different OTUs into two existing cladistic matrices. In both cases, Miocaperea was phylogenetically bracketed between juvenile and adult Caperea. Given this, and relatively slow change in the neobalaenid lineage and neoteny within the ontogeny of modern Caperea, Miocaperea and Caperea could be end-members of a late Miocene-Holocene anagenetic lineage undergoing evolutionary stasis. Ultimately, this does raise additional red flags for interpreting the relationships of cetaceans based on juvenile specimens (e.g. Nannocetus eremus, Parietobalaena palmeri).





Lunge feeding - otherwise known as gulp feeding - is one of the more derived means by which baleen whales filter feed for prey. As discussed above (see Boessenecker and Fordyce 2015: Waharoa) skim feeding consists of swimming slowly through the water column and continuously filtering out planktonic prey - this is utilized by modern right whales, probably Caperea, and inferred in eomysticetids. Gray whales feed by ingesting large volumes of sediment and filtering out small benthic crustaceans. Rorquals (humpbacks, blue, fin, minke whales) lunge feed - they swim fast towards prey and rapidly open the mouth and close it; water is expelled by the slowly contracting throat pouch. Many fossil baleen whales from the Oligocene of New Zealand - particularly the Duntroonian stage (27-25 Ma) - are eomysticetids, but by the Waitakian (25-23 Ma) are much more rare, and early "Kelloggithere" like mysticetes are present - these are poorly known, poorly understood whales like Parietobalaena; Mauicetus parki from the Waitakian (Otekaike Limestone, Milburn Limestone) of NZ is a prime example. Their relationships are unclear, and do not belong within the true Cetotheriidae, and a number of other families have been proposed. This new study reports perhaps the oldest member of this grade, Horopeta umarere, from the transition between the Kokoamu Greensand and the Otekaike Limestone in south Canterbury, New Zealand (same locality as one of the juvenile specimens of Waharoa ruwhenua). This whale has a partial skull that was disarticulated and bioeroded and thus many of the bones do not articulate, but the braincase is otherwise well preserved and includes immaculately preserved earbones - which are weird looking. They resemble the younger Mauicetus parki, but differ from pretty much all other Chaeomysticeti (except the more archaic eomysticetids) in lacking fusion of the posterior process of the earbones, indicating rather archaic status amongst the mysticetes. The mandibles are huge with a wide cross section and - most importantly - are laterally bowed like a humpback whale. These mandibular features are consistent with lunge/gulp feeding, and represent the geochronologically earliest occurrence of such adaptations. Horopeta also has a rather large, robust sternum with attachment points for multiple ribs - and is thus more primitive than the delicate platelike sternum of eomysticetids like Waharoa and Tokarahia. More strange mysticetes have yet to be described from the Oligocene of New Zealand (and Washington, U.S.A.) and will certainly complicate the emerging picture of early mysticete evolution.



            Elephant seals (Mirounga spp.) are the largest members of Carnivora and the most sexually dimorphic of all mammals, with males weighing and measuring many times larger/longer than females and having extreme ritualized behavior and bizarre probosces for display. Elephant seals live in the Antarctic and Southern Ocean as well as the eastern North Pacific. Despite having well-studied ecology and behavior, virtually nothing is known of their evolution. Bits and pieces have been mentioned, but have never been described until this new paper by Ana Valenzuela and others on middle-late Pleistocene records of Mirounga. These fossils include skull fragments and a partial mandible and some other fragments from Mejillones in Chile, and represents the first described fossil record of elephant seals. The fossils are not very old – and most other undescribed records of Mirounga are also Pleistocene, suggestive of a geochronologically shallow history of elephant seals.





Fossil pinnipeds are widely reported from the Miocene and Pliocene of South America, but most of the fossils - unlike today - are of phocid seals (aka earless or true seals) - rather than the otariid fur seals and sea lions that currently inhabit these coasts. Included within the well-sampled Pisco Formation of Peru are the well-known seals Acrophoca and Piscophoca - Piscophoca is a generalized and monk seal-like, whereas Acrophoca has an unusually elongate, narrow skull. Both of these have also been reported from the Bahia Inglesa locality in Chile. In 2012, an additional phocid seal similar to Piscophoca but with enlarged cheek teeth (and therefore with a possible durophagous diet) was named Hadrokirus. This new paper by Ana Valenzuela-Toro and colleagues reports yet another phocid seal - Australophoca changorum - from the Pisco Formation, but this seal is tiny and approximately the size of extant ringed and Baikal seals (Pusa). Australophoca is known mostly by postcrania (humerus, radius, innominate, femur, calcaneum, astragalus) and is too incomplete to be coded into a phylogenetic analysis, but it is probably a monachine seal (southern seal) rather than a phocine (northern seal) based on an elongate deltopectoral crest of the humerus, and lacking an entepicondylar foramen in the humerus. Also, nearly all southern hemisphere fossil phocids are monachines (one notable possible exception is Kawas benegesorum from Argentina) so this is hardly surprising. The epiphyses of all specimens of Australophoca are completely fused, indicating adult status, and additional specimens are recorded from Bahia Inglesa in Chile. The tiny adult is surprising, as most southern hemisphere pinnipeds are quite large, with the exception of the Juan Fernandez and Galapagos fur seals (Arctocephalus phillippii and Arctocephalus galapagoensis, respectively) which curiously inhabit the west coast of South America today. These authors point out that the range in body size observed amongst Mio-Pliocene phocid assemblages from Peru and Chile is comparable to that observed today in Alaskan waters. Sometime during the late Pliocene or Pleistocene this diverse phocid assemblage went extinct and was replaced by a roughly modern assemblage by at least the middle or late Pleistocene judging from fragmentary fossils of younger age - perhaps owing to changes in upwelling, coastal uplift, and changes in coastal geomorphology.




Velez-Juarbe, J., and D.P. Domning. 2015. Fossil Sirenia of the West Atlantic and Caribbean region XI. Callistosiren boriquensis, gen. et sp. nov. Journal of Vertebrate Paleontology 35:1:e885034.

This study is the eleventh (!!!) installment of the series of papers dedicated to fossil sirenians from the west Atlantic and Caribbean, started by reknowned sireniologist Darly Domning - the last few contributions (9-11) have been coauthored by Jorge Velez-Juarbe, and include some spectacular finds from South Carolina, Florida, and Jorge's home territory - Puerto Rico. The holotype of Callistosiren is an impressive skull collected by Jorge back in 2005 - and it has made some appearances on his blog and on SVP posters. It's a large medium sized dugongid from the Oligocene Lares Limestone of Puerto Rico, characterized by mild rostral deflection (nowhere near as vertical as extant Dugong, but not quite as horizontal as the giant hydrodamalines I'm used to in the north Pacific) and large tusks with enamel present only on the medial surface of the tusk. Notably the ribs and vertebrae show substantially less dense bone than other sirenians. This new discovery highlights how diverse the dugongid lineage was in the Oligo-Miocene of the Atlantic and Caribbean basins; in the North Pacific, there tends to be only one or two sirenians present (possibly owing to competition with desmostylians?) whereas earlier work by Jorge has already demonstrated that many Atlantic, Caribbean, and Indian ocean sirenian faunas are characterized by multispecies assemblages with evident niche partitioning. Callistosiren is the first sirenian recorded from the late Oligocene (Eocene and early Oligocene examples are already known - e.g., Pezosiren, Priscosiren), and an undescribed halitheriine dugongid is also known from the coeval Mucabarones Sand in Puerto Rico. Rostral deflection and tusk size indicate that Callistosiren likely fed on rhizomes of relatively large seagrasses, and the authors further hypothesize that the low density of postcrania - virtually unknown in all other post-Eocene sirenians - may be an adaptation for deeper diving and foraging at greater depths.





Sperm whales are some of the largest animals to have ever lived, and the largest non-filter feeding predators in the world. The public, however, is generally only familiar with the giant sperm whale Physeter - yet two other tiny sperm whales, the rare pygmy and dwarf sperm whales (Kogia spp.) are quite fascinating in their own right. Kogia, placed in its own family Kogiidae by most contemporary cetologists, shares several features with the much larger Physeter such as a convex toothless palate, a supracranial basin, extreme cranial asymmetry, lower teeth lacking enamel, and an elongate mandibular symphysis. Kogiids and physeterids share a common origin someplace around the middle or early Miocene (judging from the age of the oldest known crown physeteroid, Aulophyseter morricei from the Sharktooth Hill Bonebed of California). This study reports a new kogiid, Nanokogia isthmia, from the upper Miocene Chagres Formation of Panama. The first specimen discovered, a referred braincase, was collected by the lead author Jorge Velez-Juarbe while a postdoc student in the Panama Canal Project. Other fossil kogiids are somewhat larger than extant Kogia, such as Scaphokogia (late Miocene, Peru) and Aprixokogia (early Pliocene, North Carolina). The skull of Nanokogia is somewhat smaller and similar in size to extant Kogia, but differs in having a narrower braincase and somewhat more elongate rostrum. Unlike Aprixokogia and many other fossil physeteroids, Nanokogia shares with extant Kogia and Scaphokogia a lack of upper teeth. Nanokogia is most similar to Praekogia cedrosensis (late Miocene, Baja California) and extant Kogia, and plots out as closely related to each in the cladistic analysis. Modern Kogia has a much smaller spermaceti organ than Physeter (the spermaceti organ dorsally overlies the melon - these two organs make up the classic soft tissue "forehead" of Physeter). An enlarged premaxillary sac fossa in Nanokogia, like Praekogia and Scaphokogia, seems to indicate these extinct dwarf sperm whales retained a well-developed spermaceti organ - but lost or reduced in Kogia and the early-mid Miocene kogiid Thalassocetus. Lastly, the authors point out that during the late Miocene, a much higher level of cranial disparity involving the feeding apparatus is apparent amongst physeteroids (paralleling other groups of late Miocene-Pliocene cetaceans as well).



This is one of the strangest papers on fossil marine mammals this year, and I do not mean that in a bad way - it's really a good example of thinking outside the box when it comes to applying fossil vertebrates towards answering questions outside the realm of vertebrate paleontology. It all begins in 1964, when a young undergraduate student from Yale interested in paleoanthropology was on a field expedition with Bryan Patterson in the Turkana Basin in Kenya and found what everyone assumed to be a weird turtle shell. Later on, it was prepared and discovered to be a cetacean - and not only that, but a rare beaked whale (Ziphiidae). Mead's discovery "derailed" his future in paleoanthropology and drove him towards studying cetaceans - he produced a spectacular dissertation on dissecting out the facial region of modern odontocetes in order to investigate the source of echolocation-related sound production, and quickly became an expert on the anatomy and biology of beaked whales. One of his first papers (Mead, 1975) focused on the Turkana ziphiid. Then, some years later, the specimen went missing, and wasn't rediscovered until somebody cleaned out Stephen J. Gould's old office at Harvard in 2011, which was temporarily being used for storage. The importance of this specimen actually lies in its geologic context - the Turkana Basin is entirely terrestrial, and Mead speculated that it was an individual that swam up a river and became stranded. Wichura et al. use this in conjunction with data on how far modern oceanic cetaceans have swam up rivers to put a maximum elevation of about 30 meters above sea level on this fossil at the time, indicating it must have swam 600-700 km from the hypothesized shoreline at the time. During the early middle Miocene, at the time of the stranding, the coastal plain in this area consisted entirely of tropical rainforest with significant rainfall. Sometime after, the entire region began to uplift and it became very arid - leading to the first savannas in east Africa, an event thought to have driven the earliest human ancestors (e.g. Ardipithecus, australopithecine hominins) from the safety of the forest and onto the plains. Timing of this uplift has been poorly constrained, and the occurrence of this ziphiid so far inland now indicates that uplift must have taken place sometime after 17 Ma.