Sunday, July 26, 2015

Summer adventures, part 1: Halfmoon Bay field recon

 I've got quite a bit to catch up on from this summer - I've been busy (too busy, in fact). So, here's a selection of photos from the first part of our vacation back in the USA. We didn't waste much time heading back out to some choice localities in Halfmoon Bay. However, the drought and lack of erosion/storms has really taken its toll on local fossil sites, and as a result the beaches are high and the fossils hidden under a year's worth of dust and grime.


Sarah had a bit of a spill on the way down to the beach - in one gulley there was a thin layer of sand overlying (and hiding) a thicker layer of mud, which she jumped down onto from a log.


A Clinocardium cockle peeking out from the sand.


A pretty fragment of bull kelp sitting on the beach.


Several years ago I spotted this huge thing weathering out of the cliff about 25 feet above the beach. I got a better photograph of it in the field, and finally figured out what it is. I always knew it was some sort of a huge cetacean skull, probably baleen whale, but couldn't make heads or tails out of its shape.


Here's a marked up version of the photo. This clearly shows that it's the posterior end of an upside-down baleen whale braincase- likely a balaenopterid whale - poking out, with some of the left braincase broken away and missing. The condyles, foramen magnum, right exoccipital, and even a tympanic bulla are evident. Judging from how far up this is, the skull is well over a meter wide, putting it somewhere in the size range of a Sei whale (Balaenoptera borealis). This specimen is a bit of a heartbreaker, because it would be impractical - if not impossible - to safely collect. People have seen this photo and suggested ropes, scaffolding, jackhammers, and all sorts of wild ideas but the simple truth is 1) digging that far in would likely trigger a cliff collapse and 2) far more easily collectable specimens are waiting to be collected on other beaches, without the need of all sorts of equipment I don't have the training or funding to operate.


This hole was dug five years ago by my field assistant/fossil buddy Chris Pirrone (attorney at law), and yielded a beautiful little "river" dolphin skull with a partial rostrum, mandible, and left and right tympanoperiotics which I referred to Parapontoporia sternbergi in my 2013 Geodiversitas paper.


Gooseneck barnacles and a single mussel poking out.


A piddock clam whose rocky home is being eroded more quickly than it can bore, beautifully showing how it forms boreholes.


A large green anemone lightly dusted with sand from the last high tide, within a shallow sandy tidepool.
 

View of the dramatic cliffs of Purisima Formation at the northern side of Tunitas Beach - one of the most scenic beaches in Halfmoon Bay, if not also one of the dirtiest; it's difficult to get to, and most people who go there to have barbecues and drink leave all of their trash in kind of a big heap at the bottom of the trail.


Stay classy, Halfmoon Bay.


Vertebrate fossils here are rare - this was my first discovery - a couple of associated dolphin vertebrae. The rock was far too hard to even think about removing them.


Invertebrates are not rare, however, and clusters of the slipper shell Crepidula princeps are quite common, such as this rather nice example.


The Purisima Formation here reflects deeper shelf sedimentation, and the traces can be quite large; here's a medium-sized Teichichnus trace. Elsewhere in the Purisima Formation Teichichnus traces can exceed 1 meter diameter (!) and approach 2 meters (!!!).


Here's a thalassinidean shrimp claw, complete with the dactyl and chela.


My wife hard on the search for fossils.

Saturday, July 25, 2015

The Coastal Paleontologist returns!

Hey all!

It's been a while, and a lot has happened since I took a bit of a break. All good, mind you. I took a break from blogging in March so that I could focus on something that was a tad more important - finishing my Ph.D. I submitted my doctoral thesis for external review in February. At Otago and elsewhere in NZ, the Ph.D. finalization process is a bit more hair-raising than in the USA. In the USA, you give your committee (mostly all in your deptartment, with perhaps one external reviewer) weeks before your defense date; they read it, and at your defense, give you a list of final corrections to make - and upon completion, you submit the final thesis and you're basically done. The point is, you pick the schedule. At Otago, all reviewers are external (at least for our lab's research, since there aren't really any other cetacean morphologists in New Zealand). When you submit, your scholarship stops, and you have the option of starting a publishing bursary - which has a maximum of three months. So, you hope that your reviewers are kind enough to get their reviews back to you before your funding runs out, as you either have the choice of 1) leaving the country before your reviews come in or 2) living in a cardboard box in an alleyway and waiting (NZ is prohibitively expensive).

Initially I had opted for option 1, and in fact had already bought my plane tickets when I heard that my reviews were miraculously coming in two weeks before I was set to fly home and we scrambled to get a Skype Ph.D. defense set up. Other students had to opt for option 1, and some reviewers who couldn't be bothered took longer than three or four months. Fortunately I didn't have to worry about that, as all of my reviewers kindly returned their commentary within two months. A week and a half after passing my Ph.D. oral exam, Sarah and I hopped on a plane and headed back to the USA - where we were immediately amazed not only at the nice weather (winter in California is often better than summer weather in Dunedin) but also at how cheap groceries are (we spent on average 200-300$ on groceries a week).

We didn't wait long until we went out to do summer fieldwork along the California coast - we've gone out and visited fossil sites in Halfmoon Bay, Santa Cruz, Marin County, and Mendocino County, as well as going to Lake Tahoe, Monterey Bay, San Francisco, Berkeley, and other great spots. I'll be doing a series of posts on summer paleo adventures soon.





Special delivery from down under: big beautiful hardbound copy of my thesis, in red!


Last week I found out that my thesis was formally accepted by the school and that I will in fact be graduating on August 15, after which I will be Dr. Robert Boessenecker (thank you very much), and that my thesis will be added to the "List of Exceptional Doctoral Theses" for the University of Otago Division of Sciences - a prestigious designation given only to the top 10% of theses in the school (so, basically I got an "A" or "A+" on my last piece of schoolwork ever). Let me explain why that's amazing: I was a D average student in high school, and perhaps a C average student my first few years of my Bachelor's program. I was never a good student until the end of my undergraduate career; I think the first time I ever got a 4.0 GPA was during my master's program (and, at that, only got a "B" in a single class during my master's - the only blight on an otherwise perfect record). So, it's really just been the last 6-7 years or so. They say graduate school is harder - and in some ways, it is - but because I actually care about the subject, I pour my heart and soul into it (maybe too much, in some cases), and so regardless of how hard grad school is, in most ways it just became easier and easier.






Museum curator Mace Brown with one of the Charleston specimens I'll be working on - an adult eomysticetid skull, possibly Micromysticetus rothauseni.


Which brings me to my last and final statement, er announcement, really. In two weeks, Sarah and I will be packing up everything from our brief tenure in California to drive to the east coast, where I'll start my first job as an adjunct instructor in geology and paleontological researcher at the College of Charleston in South Carolina. The position started out as a postdoc offer to study fossil cetaceans from the Oligocene of South Carolina that are in College of Charleston collections, and was upgraded to an adjunct position which will give me a good opportunity to get quite a bit more teaching experience. We're looking forward to moving down south; I've already been to Charleston, and fell in love with the place after being there for an hour. I've updated the title of the blog; no longer being down under, and soon to be in Dixie, the name of the blog is now "The Coastal Paleontologist - Dixie Edition".

More to come - stay tuned for some coverage of our summer paleo adventures!

Sunday, March 8, 2015

Advances in marine vertebrate taphonomy - last 5 years (2010 to early 2015)



The major focus of this blog is fossil marine vertebrates, but my secondary research interest is taphonomy - the study of fossil preservation. For a number of reasons, the preservation of terrestrial organisms is much better understood and more frequently studied than that of marine organisms. Many who dabble in marine taphonomy come at it from a background in marine vertebrate paleontology, or perhaps from nonmarine taphonomy; the body of knowledge available to us in this field is sort of cobbled together and no good summary articles really exist for the novice. People die in the ocean and wash up on beaches all the time - but surprisingly, the focus on studying forensic taphonomy in marine settings is even proportionally smaller than the marine taphonomic focus within paleontology. When one comes from an auxiliary discipline, it's easy to miss some of the more recently published, relevant articles in marine vertebrate taphonomy. So, to help out anyone with an interest in the preservation of marine vertebrates - here's a (hopefully) comprehensive list of publications from the past 5 years that you may not have noticed. If there is something that I've missed, I want to know! I'd love to include it. Abstracts are copied/pasted below as well.

Acosta-Hospitaleche, C., Marquez, G., Perez, L.M., Rosato, V., and Cione, A.L. 2011. Lichen bioerosion on fossil vertebrates from the Cenozoic of Patagonia and Antarctica. Ichnos 18:1-8.

Different traces occur on fossil bones and teeth coming from the Early Miocene Gaiman Formation (Patagonia, Argentina). Most traces were attributed to the action of terrestrial and marine predators and scavengers. However, other traces on bones and teeth from this unit and one tooth from the Eocene La Meseta Formation (Antarctica) are attributed to chemical corrosion by lichens in recent times, that is, in a very late diagenetic time. The living lichens and calcium oxalate deposits occurring on the traces and their particular pattern indicates that they were not produced by vegetal roots. The lichens include reproductive structures which allowed a proper determination. A kind of corrosion pattern (Type 1) on bones and teeth from Patagonia is associated to Sarcogyne orbicularis Korber, Verrucaria sp. Schrad, and Buellia aff. punctiformis (Hoff.) Massal. The lichen Aspicilia aff. aquatica produced rounded holes on an Antarctic tooth (Type 2). On the same tooth, the epilithic lichen Caloplaca sp. Th. Fries did not leave any kind of mark on the enameloid.

Anderson, G.S., and Bell, L.S. 2014. Deep coastal marine taphonomy: investigation into carcass decomposition in the Saanich Inlet, British Columbia using a baited camera. PLoS One 9:e110710.

Decomposition and faunal colonization of a carcass in the terrestrial environment has been well studied, but knowledge of decomposition in the marine environment is based almost entirely on anecdotal reports. Three pig carcasses were deployed in Saanich Inlet, BC, over 3 years utilizing Ocean Network Canada’s VENUS observatory. Each carcass was deployed in late summer/early fall at 99 m under a remotely controlled camera and observed several times a day. Dissolved oxygen, temperature, salinity, density and pressure were continuously measured. Carcass 1 was immediately colonized by Munida quadrispina, Pandalus platyceros and Metacarcinus magister, rapidly scavenged then dragged from view by Day 22. Artifacts specific to each of the crustaceans’ feeding patterns were observed. Carcass 2 was scavenged in a similar fashion. Exposed tissue became covered by Orchomenella obtusa (Family Lysianassidae) which removed all the internal tissues rapidly. Carcass 3 attracted only a few M. quadrispina, remaining intact, developing a thick filamentous sulphur bacterial mat, until Day 92, when it was skeletonized by crustacea. The major difference between the deployments was dissolved oxygen levels. The first two carcasses were placed when oxygen levels were tolerable, becoming more anoxic. This allowed larger crustacea to feed. However, Carcass 3 was deployed when the water was already extremely anoxic, which prevented larger crustacea from accessing the carcass. The smaller M. quadrispina were unable to break the skin alone. The larger crustacea returned when the Inlet was re-oxygenated in spring. Oxygen levels, therefore, drive the biota in this area, although most crustacea endured stressful levels of oxygen to access the carcasses for much of the time. These data will be valuable in forensic investigations involving submerged bodies, indicating types of water conditions to which the body has been exposed, identifying post-mortem artifacts and providing realistic expectations for recovery divers and families of the deceased.

Baldanza, A., Bizzarri, R., Famiani, F., Monaco, P., Pellegrino, R., and Sassi, P. 2013. Enigmatic, biogenically induced structures in Pleistocene marine deposits: a first record of fossil ambergris. Geology 41:1075-1078.

Probable fossil ambergris occurs within early Pleistocene shallow-marine clay deposits in western Umbria (central Italy). More than 25 large, permineralized structures are scattered over an area of ~1200 m2. These are commonly convex to elongated, helicoidal to concentric, calcium carbonate–rich structures, 30–60 cm high and 60–120 cm wide. Permineralized squid beaks and altered organic matter occur inside these structures. Preliminary chemical data reveal the presence of organic molecules compatible with the degradation of cellular lipids, whose cholic acids indicate the presence of mammalian gastric or intestinal activity; eight free amino acids were also found. The results allow the identifi cation of these structures as intestinal products of sperm whales living ~1.75 m.y. ago. The described fossil structures represent the only known example of Pleistocene sperm whale coprolites.

Barnes, K.M., and Hiller, N. 2010. The taphonomic attributes of a Late Cretaceous plesiosaur skeleton from New Zealand. Alcheringa 34:333-344.

The pre-burial history of a partial elasmosaurid plesiosaur skeleton is reconstructed from analysis of the distribution and modification of bones preserved in a calcareous concretionary mass. The specimen lacks the skull, cervical vertebrae, left limb bones and some girdle elements, but the remaining bones are interpreted to have been deposited on the sea floor from a semi-buoyant carcass and their relative positions modified by the action of scavengers. Bioerosive agents caused loss of bone, particularly on joint surfaces and vertebral centra, as the carcass lay exposed on the sea floor, perhaps for several years before burial.

Beardmore, S.R., Orr, P.J., Manzocchi, T., and Furrer, H. 2012. Float or sink: modelling the taphonomic pathway of marine crocodiles (Mesoeucrocodylia, Thalattosuchia) during the death-burial interval. Palaeobiodiversity and Palaeoenvironments 92:83-98.

A taphonomic model is erected for a dataset of 19 Steneosaurus (Mesoeucrocodylia; Thalattosuchia) from the Toarcian Posidonienschiefer Formation (Lower Jurassic) of Germany. These were deposited in a quiet-water, marine, basin. Their taphonomy is compared with that of an additional seven thalattosuchians from other Jurassic localities (Peterborough and Yorkshire, UK; Nusplingen, Germany). The skeletal taphonomy of the specimens is assessed in terms of the articulation and completeness of nine skeletal units. Steneosaurus from the Posidonienschiefer Formation exhibit variable levels of articulation in the nine units. Completeness also varies but the head, neck and dorsal units are complete in all specimens. Carcasses reached the sediment–water interface shortly after death. Loss of fidelity occurred primarily as individuals lay on the sediment, and disarticulated elements tended to remain in the vicinity of the carcass. Those elements absent from specimens are the smaller, more distal, bones of the limbs and tail; these were removed preferentially by weak bottom currents. Smaller specimens are consistently less complete. Specimens from other localities broadly follow the same taphonomic pathway, suggesting a consistent pattern for the skeletal taphonomy of the carcasses of marine crocodiles. Loss of completeness in some specimens is more exacerbated, the result of stronger current activity at the sediment–water interface.

Beardmore, S.R., Orr, P.J., Manzocchi, T., Furrer, H., and Johnson, C. 2012. Death, decay, and disarticulation: modelling the skeletal taphonomy of marine reptiles demonstrated using Serpianosaurus (Reptilia; Sauropterygia). Palaeogeography, Palaeoclimatology, Palaeoecology 337-338:1-13.

Taphonomic models for fossil vertebrates are designed to reconstruct processes that affected carcasses during the transition from biosphere to geosphere, in particular in the interval between death and burial. To circumvent various limitations in existing methodologies, a new taphonomic method, assessing vertebrate skeletons as nine anatomical units (the head, neck, dorsal, tail, ribs and four limbs) scored independently for two characters (articulation and completeness), was developed. The potential of the method is demonstrated using the Triassic marine reptile Serpianosaurus from Monte San Giorgio, Switzerland. Specimens are preserved in alternations of black shale and dolomite, representing normal background sediment and event beds respectively, deposited into a shallow, intra-platform basin. All specimens exhibit disarticulation of skeletal elements though loss of completeness varies considerably.Minor loss of fidelity occurred during the ‘floating phase’, but individuals reached the sediment-water interface relatively soon after death, and largely intact, where they decayed during the ‘residence phase’. Carcasses allowed to reach extensive states of decay became prone to the effects of weak bottom currents, resulting in removal of elements. The episodic deposition of event beds rapidly buried individuals at various stages of decay, inhibiting further disarticulation and loss of completeness.

Becker, M.A., and Chamberlain, J.A. 2012. Squalicorax chips a tooth: A consequence of feeding-related behavior from the lowermost Navesink Formation
(Late Cretaceous: Campanian-Maastrichtian) of Monmouth County, New Jersey, USA. Geosciences 2:109-129.

Chipped and broken functional teeth are common in modern sharks with serrated tooth shape. Tooth damage consists of splintering, cracking, and flaking near the cusp apex where the enameloid is broken and exposes the osteodentine and orthodentine. Such damage is generally viewed as the result of forces applied during feeding as the cusp apex impacts the skeletal anatomy of prey. Damage seen in serrated functional teeth from sharks Squalicorax kaupi [1] and Squalicorax pristodontus [1] from the late Cretaceous lowermost Navesink Formation of New Jersey resembles that occurring in modern sharks and suggests similar feeding behavior. Tumbling experiments using serrated modern and fossil functional shark teeth, including those of Squalicorax, show that teeth are polished, not cracked or broken, by post-mortem abrasion in lowermost Navesink sediment. This provides further evidence that chipped and broken Squalicorax teeth are feeding-related and not taphonomic in origin. Evolution of rapid tooth replacement in large sharks such as Squalicorax ensured maximum functionality after feeding-related tooth damage occurred. Serrated teeth and rapid tooth replacement in the large sharks of the Mesozoic and Cenozoic afforded them competitive advantages that helped them to achieve their place as
apex predators in today’s ocean.

Belaustegui, Z., de Gibert, J.M., Domenech, R., Muniz, F. & Martinell, J. 2011. Taphonomy and paleoenvironmental setting of cetacean remains from the middle Miocene of Tarragona (NE Spain). Geobios 44:19-31.

A new finding of a marine mammal is documented from the middle Miocene of El Camp basin in Tarragona (NE Spain). The incomplete and disarticulated bone remains belong to the skeleton of a juvenile cetacean. These remains appear deposited above a transgression surface and included within a glauconitic calcisiltite layer. This unit constitutes the beginning of a shallowing-upwards sequence and was deposited under low energy conditions and low sedimentation rates in a middle-outer platform setting. This context was responsible for the long exposure of the remains and, consequently, an extension of the biostratinomic stage. These conditions favored the natural decomposition and disarticulation of the carcass, allowing the action of different types of scavenging organisms. The interpretation of the paleoenvironmental setting is based in the combination of different datasets: taphonomic data of the bone remains, paleoecologic and taphonomic information provided by the fauna associated to the bones, and ichnologic and sedimentologic interpretation of the sediments where the fossils are included. Combination of such different proxies enables a very good characterization of the paleoenvironmental context of the studied fossils.

Belaustegui, Z., de Gibert, J.M., Domenech, R., Muniz, F. & Martinell, J. 2012: Clavate borings in a Miocene cetacean skeleton from Tarragona (NE Spain) and the fossil record of marine bone bioerosion. Palaeogeography, Palaeoclimatology, Palaeoecology 323–325, 68–74.

Clavate borings found in the tympanic bulla of a Miocene cetacean from El Camp de Tarragona Basin constitute the first evidence of the ichnogenus Gastrochaenolites in bones of an autochthonous cetacean carcass. Previous records of similar trace fossils on marine bones were described from transported or reworked remains. Based on their morphology and ichnotaxonomy, the borings are assigned to the activity of pholadid bivalves, which would have colonized the skeletal carcass on the sea floor after removal of covering soft tissues. Sedimentological and paleontological data indicate a low-energy depositional setting with low sedimentation rate, which would have provided the temporal window for bivalve colonization. This new finding contributes to widen our knowledge of bioerosion in marine vertebrate skeletons.

Bianucci, G. and P. D. Gingerich. 2011. Aegyptocetus tarfa, n. gen. et sp.
(Mammalia, Cetacea), from the middle Eocene of Egypt: clinorhynchy,
olfaction, and hearing in a protocetid whale. Journal of Vertebrate
Paleontology, 31:1173–1188.

A new protocetid archaeocete, Aegyptocetus tarfa, is represented by a nearly complete cranium and an associated partial skeleton. The specimen was recovered when marbleized limestone was imported commercially to Italy and cut into decorative facing stone. It came from middle Eocene Tethyan marine strata of the Gebel Hof Formation of Wadi Tarfa in the Eastern Desert of Egypt. Exceptional preservation and preparation enables study of some internal features of the skull as well as its external morphology. The skull of Aegyptocetus is unusual in having the rostrum and frontal portions of the cranium deflected more ventrally relative to the braincase than is typical for archaeocetes. This ventral deflection, clinorhynchy, is a rare specialization related to feeding or hearing that is widely distributed across mammals. Aegyptocetus has well-developed ethmoidal turbinal bones, indicating retention of a functional sense of smell. It also has cranial asymmetry, thinning of the lateral walls of the dentaries, enlarged mandibular canals, and thinning of the anterolateral walls of the tympanic bullae, indicating enhanced ability to hear in water. Neural spines are long on thoracic vertebrae T1 through T8, suggesting that Aegyptocetus was able to support its weight on land like other protocetids. This combination of terrestrial and aquatic characteristics is consistent with interpretation of protocetids as semiaquatic. The pattern of tooth marks preserved on the ribs of Aegyptocetus indicates that the individual studied here was attacked by a large shark, but it is not certain whether
this was the cause of death.

Bianucci, G., Sorce, B., Storai, T., and Landini, W. 2010. Killing in the Pliocene: shark attack on a dolphin from Italy. Palaeontology 53:457-470.

Shark bite marks, including striae, sulci and abrasions, in a well-preserved fossil dolphin skeleton referred to Astadelphis gastaldii (Cetacea, Delphinidae) from Pliocene sediments of Piedmont (northern Italy), are described in detail. The exceptional combination of a fossil dolphin having a significant part of the skeleton preserved and a large number of bite marks on the bones represents one of the few detailed documentations of shark attack in the past. Most bite marks have been referred to a shark about 4 m long with unserrated teeth, belonging to Cosmopolitodus hastalis, on the basis of their shape and their general disposition on the dolphin skeleton. According to our hypothesis, the shark attacked the dolphin with an initial mortal bite to the abdomen from the rear and right, in a similar way as observed for the living white shark when attacking pinnipeds. A second, less strong, bite was given on the dorsal area when the dolphin, mortally injured, probably rolled to the left. The shark probably released the prey, dead or dying, and other sharks or fishes probably scavenged the torn body of the dolphin.

Boessenecker, R.W. and F.A. Perry. 2011. Mammalian bite marks on juvenile fur seal bones from the late Neogene Purisima Formation of Central California. Palaios, 26:115–120.

Fossils of extinct fur seals and walruses (Carnivora: Pinnipedia) occur within rich vertebrate fossil assemblages recovered from the shallow marine Mio-Pliocene Purisima Formation, central California. Two isolated postcranial bones—a humerus and a radius—belonging to a juvenile fur seal (Pinnipedia: Otariidae) exhibit circular depressions. These bone modifications are associated with radial and circular fractures, and are characterized by inward displacement of the cortex. These depressions lack features typical of erosive invertebrate borings, trampling damage from media (5substrate) interaction, puncturing by another object during diagenetic compaction, such as a clast embedded or associated with the modification, or pathologic bone modification. These features are best interpreted as tooth marks. These tooth marks lack certain characteristics of commonly reported marks inflicted by shark teeth, such as linear gouges and subparallel scrapes formed by xiphodont
and serrated teeth. These bone modifications instead exhibit a circular shape and inward displacement of the cortex, consistent with puncturing by a conical mammal tooth. The size and distribution of the tooth marks, in concert with the known vertebrate assemblage from the Purisima Formation, indicate several possible producers of the bone modifications: a pilot whale or beluga-like cetacean, a terrestrial carnivore, a dusignathine or odobenine walrus, or a case of infanticide by a conspecific otariid.

Boessenecker, R.W. 2013. Taphonomic implications of barnacle encrusted sea lion bones from the middle Pleistocene Port Orford Formation, coastal Oregon. Journal of Paleontology 87:657-663.

Fossil evidence of barnacle encrustation of vertebrate bones is reported from the middle Pleistocene Port Orford Formation of southern coastal Oregon. This material includes two associated thoracic vertebrae and a femur referable to the extinct sea lion Proterozetes ulysses that are encrusted by 1400 individual barnacles (cf. Hesperibalanus hesperius), and a scapula of Zalophus californianus with barnacle attachment scars. In areas, the encrusting barnacles exhibit a roughly bimodal size range, and small barnacles are observed directly encrusting other larger individuals. The size, probable age, and lifespan of extant Hesperibalanus hesperius indicates a minimum period of four to seven months of seafloor exposure between decomposition and burial, although this estimate must be longer because at least two colonization events are represented. Barnacle attachment traces are identified as Anellusichnus circularis. The wide distribution of barnacles on some of these bones suggests these were regularly overturned by bottom currents, which would prevent barnacles from being smothered by prolonged contact with the sediment. Detailed study of barnacle-induced trace fossils on these specimens suggests that episkeletozoans and their traces can be useful sources of data regarding the biostratinomic history of vertebrate fossils.

Boessenecker, R.W. and Fordyce, R.E. 2014. Trace fossil evidence of predation upon bone-eating worms on a baleen whale skeleton from the Oligocene of New Zealand. Lethaia DOI: 10.1111/let.12108.

The osteophagous worm Osedax (Annelida: Siboglinidae) colonizes vertebrate bones in deep-sea environments globally. Osedax bioerosion of modern bones suggests a potentially destructive agent in the marine vertebrate fossil record, but the dearth of published reports of abundant Osedax traces suggests an uncertain taphonomic influence of this organism. This study reports Osedax traces (Osspecus boreholes, pockmarks and collapsed galleries) in an Oligocene baleen whale (Cetacea: Eomysticetidae) from New Zealand, which constitute the first record of fossil Osedax traces from the southern hemisphere. Some Osedax traces are cross-cut by linear biogenic scrape marks, implying that sharks or bony fish fed upon Osedax worms, a process which compounds or potentially accelerates worm-inflicted damage to vertebrate bones in marine environments.

Boessenecker, R.W., Perry, F.A., and Schmitt, J.G. 2014. Comparative taphonomy, taphofacies, and bonebeds of the Mio-Pliocene Purisima Formation, Central California: strong physical control on marine vertebrate preservation in shallow marine settings. PLoS One 9:e91419.

Background: Taphonomic study of marine vertebrate remains has traditionally focused on single skeletons, lagerstatten, or bonebed genesis with few attempts to document environmental gradients in preservation. As such, establishment of a concrete taphonomic model for shallow marine vertebrate assemblages is lacking. The Neogene Purisima Formation of Northern California, a richly fossiliferous unit recording nearshore to offshore depositional settings, offers a unique opportunity to examine preservational trends across these settings. Methodology/Principal Findings: Lithofacies analysis was conducted to place vertebrate fossils within a hydrodynamic and depositional environmental context. Taphonomic data including abrasion, fragmentation, phosphatization, articulation, polish, and biogenic bone modification were recorded for over 1000 vertebrate fossils of sharks, bony fish, birds, pinnipeds, odontocetes, mysticetes, sirenians, and land mammals. These data were used to compare both preservation of multiple taxa within a single lithofacies and preservation of individual taxa across lithofacies to document environmental gradients in preservation. Differential preservation between taxa indicates strong preservational bias within the Purisima Formation. Varying levels of abrasion, fragmentation, phosphatization, and articulation are strongly correlative with physical processes of sediment transport and sedimentation rate. Preservational characteristics were used to delineate four taphofacies corresponding to inner, middle, and outer shelf settings, and bonebeds. Application of sequence stratigraphic methods shows that bonebeds mark major stratigraphic discontinuities, while packages of rock between discontinuities consistently exhibit onshore-offshore changes in taphofacies. Conclusions/Significance: Changes in vertebrate preservation and bonebed character between lithofacies closely correspond to onshore-offshore changes in depositional setting, indicating that the dominant control of preservation is exerted by physical processes. The strong physical control on marine vertebrate preservation and preservational bias within the Purisima Formation has implications for paleoecologic and paleobiologic studies of marine vertebrates. Evidence of preservational bias among marine vertebrates suggests that careful consideration of taphonomic overprint must be undertaken before meaningful paleoecologic interpretations of shallow marine vertebrates is attempted.

Buckeridge, J.S. 2011. Taphonomy and systematics of a new Late Cretaceous verrucid barnacle (Cirripedia, Thoracica) from Canterbury, New Zealand. Palaeontology 54:365-372.

Cirripede remains (Thoracica, Verrucomorpha), found associated with the mosasaur Prognathodon waiparaensis Welles and Gregg, 1971 in glauconitic sands of the Late Cretaceous Conway Formation exposed along the Waipara River bank (mid-Canterbury, New Zealand), are identified as a new species, Verruca sauria sp. nov. On the basis of taphonomy, it is deduced that these verrucids grew on a postmortem accumulation of mosasaur bones under very quiescent conditions. The current amphitropical distribution of the earliest known verrucids, i.e. V. sauria sp. nov., V. prisca Bosquet, 1854, V. pusilla Bosquet, 1857 and V. tasmanica Buckeridge, 1983, is rationalized in the light of Tethyan palaeogeography.

Chellouche, P., Fursich, F.T., and Mauser, M. 2012. Taphonomy of neopterygian fishes from the upper Kimmeridgian Wattendorf Plattenkalk of Southern Germany. Palaeobiodiversity and Palaeoenvironments 92:99-117.

The Upper Kimmeridgian Wattendorf Plattenkalk, the oldest of the Solnhofen-type plattenkalks of southern Germany, has yielded a high number of exceptionally preserved fossils over the past several years. The high number of fossils and the fact that every bedding plane, along which the laminated rocks split, has been equally thoroughly searched for fossils, allow for qualitative as well as quantitative taphonomic investigations. For a quantitative analysis of the Wattendorf lagerstätte, four different taphofacies (A–D) were established by means of euclidean cluster analysis. For this, biostratinomic features of neopterygian fishes, primarily of the genus Tharsis, were recorded. Percentages of the occurrence of these features per layer were determined and clustered into groups of similar patterns. The taphonomic features utilised were bending of the spinal column, completeness, and skeletal articulation. Taphofacies A through D mark a change from a palaeoenvironment with only small extrinsic disturbing factors to a palaeoenvironment characterised by greater disturbance (e.g. bottom currents, fluctuating salinity). At the beginning of plattenkalk deposition, cyclic changes of the palaeoenvironment prevailed with periodic high disturbance, probably caused by storminduced flows. These events initiated mixing of the supposedly chemically stratified water body. In the upper part of the plattenkalk unit, taphofacies indicative of higher disturbance dominate, suggesting a change from stable to less stable environmental conditions in the plattenkalk basin resulting in disruption of the typical plattenkalk sedimentation. Sporadic oxygenation of bottom waters is also indicated by the style of soft-tissue preservation. Besides typical phosphatisation, a specimen of Palaeohirudo? sp. shows soft-tissue preservation through iron-oxide permineralisation.

Cione, A.L., C.A. Hospitaleche, L.M. Perez, J.H. Laza, and I. Cesar. 2010. Trace fossils on penguin bones from the Miocene of Chubut, southern Argentina. Alcheringa, 34:433–454.

Several traces of biological interaction were found on penguin bones from the basal levels (Aquitanian) of the Miocene Gaiman Formation in the lower Chubut valley of the Provincia del Chubut, Argentina. The fossil-bearing beds were deposited in littoral to sublittoral environments within sediments of mostly pyroclastic origin. We interpret many traces to have been produced by predators and/or scavengers while the penguins were still in a breeding area. Many bones show cracking marks due to aerial exposure. The material is disarticulated as is usual in recent breeding areas. Potential predators were coeval terrestrial mammals, most probably marsupial carnivores. After a marine transgression, these bones were buried or exposed on the sea bottom where they could be colonized by algae, sponges, cnidarians, and other benthic organisms. We identified sponge borings in several bones. Other traces are interpreted to have been produced by echinoderms feeding on sponges or algae. No evidence of other invertebrate predators such as muricid or naticid gastropods, or decapods was found. Finally, other traces appear to have been generated by shark and possibly teleostean vertebrates feeding on epibionts. One coracoid is interpreted to have been marked by a shark that is common in the Gaiman Formation, the carcharhiniform Galeocerdo aduncus. From an ethological (Seilacherian) classification, traces on bones from the Gaiman Formation include Domichnia (sponge perforations), Praedichnia (terrestrial marsupials, sharks, teleosteans) and Pasichnia (echinoderms). Remarkably, remains of marine organisms with skeletons made of calcium carbonate are very poorly preserved in the Gaiman Formation. Only large oysters, sparse shell fragments, skeletal moulds, and bioturbation is evident. The fossil assemblage is mainly composed of phosphatic (e.g. teeth, bones, crustacean parts) and siliceous (sponge spicules, diatoms) remains.

Danise, S., Cavalazzi, B., Dominici, S., Westall, F., Monechi, S., and Guioli, S. 2012. Evidence of microbial activity from a shallow water whale fall (Voghera, Northern Italy). Palaeogeography, Palaeoclimatology, Palaeoecology 317-318:13-26.

The fossil bones, associated carbonate cements and enclosing concretion of a Miocene mysticete from inner shelf deposits (Monte Vallassa Formation, northern Italy) were analyzed for evidence of microbial activity. Optical and scanning electron microscopy, Raman spectroscopy, and stable C and O isotope geochemistry were used for high spatial resolution microfacies and biosedimentological analyses. Whale cancellous bones were filled by different carbonate cements including microcrystalline dolomite, rhombohedral dolomite and sparry calcite. Biofabric and biominerals such as microbial peloids, clotted textures and pyrite framboids were associated with the dolomite cements. Dolomite inside cancellous bones and in the enclosing concretion showed similar isotopic values (avg δ13C: −7.12‰; avg δ18O: +3.81‰), depleted with respect to the (late) sparry calcite cement (avg δ13C: −0.55‰; avg δ18O: −0.98‰). Microcrystalline barite (BaSO4) was observed on the external surface of the bones. In addition, two different types of microborings were recognized, distinguished by their size and morphology and were ascribed respectively to prokaryote and fungal trace makers. Our results testify for the development of a diverse microbial ecosystem during the decay of a shallow water whale carcass, which could be detected in the fossil record. However, none of the observed biosignatures (e.g., microbial peloids, clotted textures) can be used alone as a positive fossil evidence of the general development of a sulfophilic stage of whale fall ecological succession. The occurrence of the hard parts of chemosynthetic invertebrates associated with fossil whale bones is still the more convincing proof of the development of a sulfide-base chemoautotrophic ecosystem.

Danise, S., and Dominici, S. 2014. A record of fossil shallow-water whale falls from Italy. Lethaia 47:229-243.

Twenty-five Neogene–Quaternary whales hosted in Italian museum collections and their associated fauna were analysed for evidence of whale-fall community development in shallow-water settings. The degree of bone articulation, completeness of the skeleton and lithology of the embedding sediments were used to gather information on relative water depth, water energy, sedimentation rate and overall environmental predictability around the bones. Shark teeth and hard-shelled invertebrates with a necrophagous diet in close association with the bones were used as evidence of scavenging. Fossil bone bioerosion, microbially mediated cementation and other mollusc shells in the proximity of the remains informed on past biological activity around the bones. The results are consistent with the hypothesis that shallow-water whale falls differ from their deep-water counterparts. Taphonomic pathways are more variable on the shelf and whale carcasses may not go through all steps of the ecological succession as recognised in the deep sea. Whilst the mobile scavenger and the enrichment opportunistic stages are well represented, chemosynthetic taxa typical of the sulphophilic stage were recovered only in one instance. The presence of a generalist fauna among the suspension feeding bivalves and carnivorous gastropods, and the extreme rarity of chemosynthetic taxa, suggest that predatory pressure rules out whale-fall specialists from shallow shelf settings as in analogous cold seep and vent shallow-water communities.

Danise, S., Twitchett, R.J., and Matts, K. 2014. Ecological succession of a Jurassic shallow-water ichthyosaur fall. Nature Communications 5: 4789.

After the discovery of whale fall communities in modern oceans, it has been hypothesized that during the Mesozoic the carcasses of marine reptiles created similar habitats supporting long-lived and specialized animal communities. Here, we report a fully documented ichthyosaur fall community, from a Late Jurassic shelf setting, and reconstruct the ecological succession of its micro- and macrofauna. The early ‘mobile-scavenger’ and ‘enrichment-opportunist’ stages were not succeeded by a ‘sulphophilic stage’ characterized by chemosynthetic molluscs, but instead the bones were colonized by microbial mats that attracted echinoids and other mat-grazing invertebrates. Abundant cemented suspension feeders indicate a well-developed ‘reef stage’ with prolonged exposure and colonization of the bones prior to final burial, unlike in modern whale falls where organisms such as the ubiquitous bone-eating worm Osedax rapidly destroy the skeleton. Shallow-water ichthyosaur falls thus fulfilled similar ecological roles to shallow whale falls, and did not support specialized chemosynthetic communities.

Diedrich, C.G., and Felker, H. 2012. Middle Eocene shark coprolites from shallow marine and deltaic coasts of the pre-North Sea Basin in central Europe. New Mexico Bulletin of Natural History and Science 57:311-318.

Middle Eocene (Paleogene, Cenozoic) transgressive marine conglomerates of two German localities in the southern Pre-North Sea basin of Central Europe contain a large number of more then 19 different large- to medium-sized shark taxa (teeth size > 4 mm). Only 0.05% of the vertebrate remains are shark coprolites (n = 556), which can be classified in five main types, most having a heteropolar-spirally-coiled morphology. These are classified into five different main shape types. Possibly the largest forms (Type A), in part containing medium sized fish bones and vertebrae, belong to megatooth and white shark ancestors (Otodus, Carcharocles, Procarcharodon), whereas the most abundant, medium-sized variable forms (Type B) might have been produced by laminid sharks (Isurus, Jaeckelotodus, Xiphodolamia, Brachycarcharias, Hypotodus, Sylvestrilamia), but the very abundant sand shark ancestor Striatolamia is expected as their main producer. Type C is rare and a thin elongated form with zigzag-heteropolar external structure (producers: ?rays/small-sized carchariniform sharks such as Galeocerdo, Pachygaleus). The smaller, including the smallest (only 3 mm) oval-round pellets, and also the unclearly heteropolar Type D oval- to round-shaped pellets have only poorly developed surface coil structures, and are preliminarily referred to sharks or rays. Rare, irregularly-formed excrement can be referred preliminarily to a crocodile producer, which supports the deltaic distal position of the Dalum site, and more shallow marine position of the Osteroden locality. At the latter, larger shark coprolites (Type A) are much more abundant, indicating more shallow marine environments, whereas at Dalum a mixture of shallow marine and deltaic palaeoenvironments were present during the Middle Eocene of the southern Pre-North Sea Basin of Central Europe.

Godfrey, S.J., and Smith, J.B. 2010. Shark-bitten vertebrate coprolites from the Miocene of Maryland. Naturwissenschaften 97:461-467.

Coprolites (fossilized feces) preserve a wide range of biogenic components, from bacteria and spores to a variety of vertebrate tissues. Two coprolites from the Calvert Cliffs outcrop belt (Miocene-aged Chesapeake Group), MD, USA, preserve shark tooth impressions in the form of partial dental arcades. The specimens are the first known coprolites to preserve vertebrate tooth marks. They provide another example of trace fossils providing evidence of prehistoric animal behaviors that cannot be directly approached through the study of body fossils. Shark behaviors that could account for these impressions include: (1) aborted coprophagy, (2) benthic or nektonic exploration, or (3) predation.

Govender, R., and Chinsamy, A. 2013. Early Pliocene (5 Ma) shark-cetacean trophic interaction from Langebaanweg, western coast of South Africa. Palaios 28:270-277.

We document an aspect of the marine paleoecology at Langebaanweg, a site that has produced an abundance of vertebrate fossils. Damage to the bone surfaces of cetacean fossils was not pathological as evident on the fossil seals from this site; the current study documents the damage and attempts to provide a parsimonious explanation. Literature reviews identified similar damage described elsewhere to be the result of shark feeding activity. Comparison of this material with Langebaanweg cetacean bones supports the interpretation that the damage resulted from shark teeth. Damage on the various skeletal elements appears to have been inflicted postmortem or, if they were made while the animal was alive, the whales did not survive the attack. Postmortem damage is also supported by the presence of bites on the dorsal, ventral, lateral, and medial surfaces of a pair of dentaries. Bites were inflicted by sharks with serrated teeth, as well as by sharks with unserrated teeth. Potential predators identified from the marks include white (Carcharodon spp.), Zambezi (bull) (Carcharhinus leucas), tiger (Galeocerdo sp.) and mako (Isurus sp.) sharks.

Eriksson, M.E., Lindgren, J., Chin, K., and Mansby, U. 2011. Coprolite morphotypes from the Upper Cretaceous of Sweden: novel views on an ancient ecosystem and implications for coprolite taphonomy. Lethaia 44:455-468.

Coprolites (fossilized faeces) are common, yet previously unreported, elements in the
Campanian (Upper Cretaceous) shallow-marine strata of Asen, southern Sweden. They are associated with a diverse vertebrate fauna and comprise at least seven different morphotypes that suggest a variety of source animals. Their faecal origin is corroborated by several lines of evidence, including chemical composition (primarily calcium phosphate), external morphology and nature of the inclusions. Preservation in a fossil coquina, interpreted as a taphocoenosis, suggests early lithification promoted by rapid entombment. This would have prevented disintegration of the faecal matter and facilitated transportation and introduction to the host sediment. The coprofabrics can generally be correlated to specific gross morphologies, supporting a morphology-determined coprolite classification. Moreover, having been deposited under presumably comparable taphonomic conditions, variations in coprofabrics infer differences in diet and or digestive efficiency of the host animal. Size and morphology of the coprolites imply that most, if not all, were produced by vertebrates and the largest specimens infer a host animal of considerable size. Two spiralled coprolite morphotypes yield bone fragments and scales of bony fish, suggesting that the producers were piscivorous sharks. Other coprolites contain inclusions interpreted as the remains of shelled invertebrates, thus indicating that they may have derived from durophagous predators and or scavengers. The occurrence of small scrapes, tracks and traces on several specimens suggest manipulation of the faeces by other (presumably coprophagous) organisms after deposition. The collective data from the Asen coprolites provide new insights into a shallow-water Late Cretaceous marine ecosystem hitherto known solely from body fossils.

Fahlke, J. M. Bite marks revisited—evidence for middle-to-late Eocene
Basilosaurus isis predation on Dorudon atrox (both Cetacea, Basilosauridae).
Palaeontologia Electronica, 15:32A:1–16.

Basilosauridae are cosmopolitan fully-aquatic archaeocete whales, represented by larger Basilosaurus isis and smaller Dorudon atrox in the middle-to-late Eocene Gehannam and Birket Qarun Formations of Egypt (ca. 38-36.5 Ma). Adult and juvenile Dorudon but only adult Basilosaurus are found in these shallow-marine deposits. Lethal bite marks on juvenile Dorudon skulls sparked the idea that adult Basilosaurus invaded calving grounds of D. atrox to prey on their young. However, there has been no direct evidence to support this idea. In this study, bite marks on specimens of juvenile D. atrox that have previously been described but not assigned to a particular tracemaker are reinvestigated, and additional bone modifications are analyzed. Applying computed tomography (CT), digital surface scanning, and three-dimensional (3D) reconstruction, the juvenile D. atrox specimens were digitally placed into the mouth of an adult B. isis. Bite marks match the dentition of B. isis. Imprints of tooth casts of B. isis in modeling clay furthermore resemble bite marks on these D. atrox specimens in shape and size. B. isis was likely a predator that included juvenile D. atrox in its diet. Prey was predominantly captured from a lateral position across the head and sometimes adjusted in the mouth prior to a more powerful bite. Scavenging of B. isis on D. atrox calves is also possible. The diet of Basilosaurus and dietary differences within the genus resemble those known in modern killer whales (Orcinus orca). B. isis is the only archaeocete known to date that possibly preyed on other cetaceans.

Gingerich, P.D. Abd-ElShafy, E., Metwally, M.H.M., Zalmout, I., and Antar, M.S.M. 2011. Paleoenvironmental and taphonomic assessemnet of Eocone marine fauna of Wadi El-Hitan and Siwa areas, Egypt. Egyptian Journal of Paleontology 11:171-190.

The Eocene vertebrates and their faunal communities present in Wadi El- Hitan - Siwa area (Egyptian Western Desert) indicate that they lived in a semienclosed basin with an open outlet to the sea and fresh water from the neighboring land. The ecological consequences of freshwater input and mixing with marine water created strong gradients within suitable physicochemical characteristics, biological activity and diversity. This type of ecological niches represents the most productive one among all marine ecosystems. The sheer quantity of fossils reflects the ample presence of various life forms that existed in the sea-waters of the Eocene time in the Egyptian Western Desert. The richness and highly diversifiable fauna found at the exposures of the studied area imposed our attention for studying and graphicalp simulation of the palaeoenvironmental parameters that controlled the formation of such assortment of organisms as well as the study of the taphonomic management of these bone accumulations.

Higgs, N.D., Glover, A.G., Dahlgren, T.G., and Little, C.T.S. 2010. Using computed-tomography to document borings by Osedax mucofloris in whale bone. Cahiers Biologie de Marine 51:401-405.

Chemosynthesis-based communities have existed on whale skeletons for over 35 million years. However little is known about the effects of Osedax boring on the bone taphonomy and ecology of the whale-fall community. In order to evaluate this important process we used micro computed-tomography (CT) to ascertain the morphology of borings produced by Osedax mucofloris on a Minke whale bone exposed on the sea-floor for eight months. CT images revealed wide, shallow sub-surface cavities where the roots eroded the bone. These cavities were restricted to the densest layer of bone and had a maximum penetration of 2.63 mm. Over the eight month period 0.67% of the bone had been degraded directly by Osedax borings. These findings suggest that the presence of Osedax can lead to the rapid degradation of whale bones, having important implications for the ecology of whale-fall communities. Furthermore, these descriptions allow the potential identification of Osedax activity at fossil whale-falls.

Higgs, N.D., Glover, A.G., Dahlgren, T.G. & Little, C.T.S. 2011: Bone-boring worms: characterizing the morphology, rate, and method of bioerosion by Osedax mucofloris (Annelida, Siboglinidae). Biological Bulletin 221, 307–316.

Osedax worms possess unique “root” tissues that they use to bore into bones on the seafloor, but details of the boring pattern and processes are poorly understood. Here we use X-ray micro-computed tomography to investigate the borings of Osedax mucofloris in bones of the minke whale (Balaenoptera acutorostrata), quantitatively detailing their morphological characteristics for the first time. Comparative thin-sections of the borings reveal how the bone is eroded at the sub-millimeter level. On the basis of these results we hypothesize a model of boring that is dependent on the density and microstructure of the bone. We also present evidence of acidic mucopolysaccharides in the mucus of the root tissue, and hypothesize that this plays an important role in the boring mechanism. We discuss the utility of these new data in evaluating Osedax trace fossils and their relevance for O. mucofloris ecology. Measured rates of bone erosion (6% per year) and evidence of enhanced sulfide release from the borings indicate that Osedax worms are important habitat modifiers in whale-fall communities.

Higgs, N.D., Little, C.T.S., Glover, A.G., Dahlgren, T.G., Smith, C.R. & Dominici, S. 2012: Evidence of Osedax worm borings in Pliocene (~3 Ma) whale bone from the Mediterranean. Historical Biology 24, 269–277.

Osedax worms subsist entirely on vertebrate skeletons on the seafloor, using root-like tissues to bore into and degrade the bones. Paleontologists have only recently begun to appreciate the possible destructive effect that these worms may have had on the marine vertebrate fossil record and little is known of their evolutionary history. Using microcomputed tomography, we document Osedax-like borings in a fossil whale bone from the Pliocene of Italy and present new data on the borings of extant Osedax worms. The fossil borings are distinguished from those of other known borers and identified as traces of Osedax activity based on diagnostic features. Our results suggest that it is necessary to isolate individual borings for the confident identification of Osedax traces. This is only the second paleogeographic occurrence of Osedax in the fossil record and indicates that by the Pliocene these worms had colonised a large portion of the world’s oceans. This is the first evidence for Osedax in the Mediterranean, past or present, and suggests that more species await discovery in this region.

Higgs, N.D., and Pokines, J.T. 2014. Marine environmental alterations to bone. Pp. 145-181 in Pokines, J., and Symes, S.A., Manual of Forensic Taphonomy. CRC Press.

No abstract.

Janssen, R., Baal, R.R. van, and Schulp, A.S. 2011. On the taphonomy of the late Maastrichtian (Late Cretaceous) marine turtle Allopleuron hofmanni. Netherlands Journal of Geosciences 90:187-196.

An exhaustive screening of public collections containing remains of the latest Cretaceous (late Maastrichtian) marine turtle Allopleuron hofmanni (Gray, 1831) from the type area of the Maastrichtian Stage (southeast Netherlands, northeast Belgium) shows the available material to represent almost exclusively adult individuals. The various skeletal elements are not preserved in proportionally equal abundance, with portions of carapace, pectoral girdle, cranium and mandible overrepresented. These observations can be explained by population characteristics and taphonomic factors. During the late Maastrichtian, while hatchlings and juveniles in all likelihood lived and fed elsewhere, extensive seagrass meadows might have supported a population of only adult marine turtles.

Kiel, S., Goedert, J.A., Kahl, W.A. & Rouse, G.W. 2010. Fossil traces of the bone-eating worm Osedax in early Oligocene whale bones. Proceedings of the National Academy of Sciences 107, 8656–8659.

Osedax is a recently discovered group of siboglinid annelids that consume bones on the seafloor and whose evolutionary origins have been linked with Cretaceous marine reptiles or to the post-Cretaceous rise of whales. Here we present whale bones from early Oligocene bathyal sediments exposed in Washington State, which show traces similar to those made by Osedax today. The geologic age of these trace fossils (~30 million years) coincides with the first major radiation of whales, consistent with the hypothesis of an evolutionary link between Osedax and its main food source, although older fossils should certainly be studied. Osedax has been destroying bones for most of the evolutionary history of whales and the possible significance of this “Osedax effect” in relation to the quality and quantity of their fossils is only now recognized.

Kiel, S., Kahl, W.A. & Goedert, J.L. 2011: Osedax borings in fossil marine bird bones. Naturwissenschaften 98, 51–55.

The bone-eating marine annelid Osedax consumes mainly whale bones on the deep-sea floor, but recent colonization experiments with cow bones and molecular age estimates suggesting a possible Cretaceous origin of Osedax indicate that this worm might be able grow on a wider range of substrates. The suggested Cretaceous origin was thought to imply that Osedax could colonize marine reptile or fish bones, but there is currently no evidence that Osedax consumes bones other than those of mammals. We provide the first evidence that Osedax was, and most likely still is, able to consume non-mammalian bones, namely bird bones. Borings resembling those produced by living Osedax were found in bones of early Oligocene marine flightless diving birds (family Plotopteridae). The species that produced these boreholes had a branching filiform root that grew to a length of at least 3 mm, and lived in densities of up to 40 individuals per square centimeter. The inclusion of bird bones into the diet of Osedax has interesting implications for the recent suggestion of a Cretaceous origin of this worm because marine birds have existed continuously since the Cretaceous. Bird bones could have enabled this worm to survive times in the Earth’s history when large marine vertebrates other than fish were rare, specifically after the disappearance of large marine reptiles at the end-Cretaceous mass extinction event and before the rise of whales in the Eocene.

Kiel, S., Kahl, W.A. & Goedert, J.L. 2013: Traces of the bone-eating annelid Osedax in Oligocene whale teeth and fish bones. Palaontologische Zeitschrift 87:161–167.

The range of substrates that the bone-eating marine worm Osedax is able to consume has important implications for its evolutionary history, especially its potential link to the rise of whales. Once considered a whale specialist, recent work indicates that Osedax consumes a wide range of vertebrate remains, including whale soft tissue and the bones of mammals, birds and fishes. Traces resembling those produced by living Osedax have now been recognized for the first time in Oligocene whale teeth and fish bones from deep-water strata of the Makah, Pysht and Lincoln Creek formations in western Washington State, USA. The specimens were acid etched from concretions, and details of the borehole morphology were investigated using micro-computed tomography. Together with previously published Osedax traces from this area, our results show that by Oligocene time Osedax was able to colonize the same range of vertebrate remains that it consumes today and had a similar diversity of root morphologies. This supports the view that a generalist ability to exploit vertebrate bones may be an ancestral trait of Osedax.

Loon, A.J. van. 2013. Ichthyosaur embryos outside the mother body: not due to carcass explosion but to carcass implosion. Palaeobiodiversity and Palaeoenvironments 93:103-109.

Some well-preserved ichthyosaurs found in the Early Jurassic Posidonienschiefer Formation at Holzmaden (Germany) have puzzled palaeontologists for a long time: their skeletons are exceptionally well preserved and their bones are almost all in situ, but the bones of their embryos are scattered, partly beyond the body limits of themother. This has been explained initially by bottom currents and later by a displacement of already disarticulated embryos during the expulsion of putrefaction gases through the disrupted body wall of the mother. It was postulated recently that this latter hypothesis is not tenable. It is argued here that both hypotheses are not tenable in their original form, but that carcass implosion may explain the various enigmatic features.

Lowemark, L. 2014. Evidence for targeted elasmobranch predation on thalassinidean shrimp in the Miocene Taliao Formation, NE Taiwan. Lethaia DOI: 10.1111/let.12101

Terrestrial and marine invertebrate organisms both leave records of their activities in
the sediment in the form of trace fossils, at least during certain stages of their ontogeny. In contrast, trace fossils produced by vertebrate organisms are scarce, although terrestrial trace fossils provide exclusive insights into the social behaviour of their producers. In the marine realm, vertebrate trace fossils are relatively rare, difficult to identify and problematic to interpret. However, in certain settings, observations on serendipitously preserved and exposed trace fossils can shed light on the predatory behaviour of marine vertebrates. In Miocene outer shelf to nearshore sandstones of the Taliao Formation in NE Taiwan, large numbers of bowl-shaped trace fossils can be observed. Morphology and size range (diameter typically 10–30 cm, average depth around 10 cm) of these trace fossils agree well with feeding traces of modern stingrays, and the trace fossil Piscichnus waitemata, which has been attributed to bottom feeding rays. Stingrays direct a jet of water from their mouths to excavate a bowl-shaped pit to expose their prey. In the material filling the excavated bowl, broken pieces of two other common trace fossils, Ophiomorpha and Schaubcylindrichnus, are often found, and in a number of cases, vertical shafts of Ophiomorpha surrounded by dispersed pieces of wall material have been observed. In contrast, surrounding sediment rarely contains this kind of broken pieces of wall material. These observations clearly indicate that stingrays specifically targeted the producers of the trace fossils: thalassinoid crustaceans and worms, respectively. The targeted predation of these relatively deep burrowers furthermore suggests that the rays used their electroreceptive organs to locate the prey; as such, direct targeting of buried prey only based on olfactory senses has been shown to be ineffective in experiments with extant myliobatiform rays.

Luksevics, E., Ahlberg, P., Stinkulis, G., Vasilkova, J., and Zupins, I. 2011. Frasnian vertebrate taphonomy and sedimentology of macrofossil concentrations from the Langsede Cliff, Latvia. Lethaia 45:356-370.

The siliciclastic sequence of the Upper Devonian of Kurzeme, Western Latvia, is
renowned for abundant vertebrate fossils, including the stem tetrapods Obruchevichthys gracilis and Ventastega curonica. During the first detailed taphonomic study of the vertebrate assemblage from the Ogre Formation cropping out at the Langs_ede Cliff, Imula River, abundant vertebrate remains have been examined and identified as belonging to one psammosteid, two acanthodian and three sarcopterygian genera; the placoderm Bothriolepis maxima dominates the assemblage. Besides fully disarticulated placoderm and psammosteid plates, separate sarcopterygian scales and teeth, and acanthodian spines, partly articulated specimens including complete distal segments of Bothriolepis pectoral fins, Bothriolepis head shields and sarcopterygian lower jaws have been found. The size distribution of the placoderm bones demonstrates that the individuals within the assemblage are of approximately uniform age. Distinct zones have been traced within the horizontal distribution of the bones. These linear zones are almost perpendicular to the dominant dip azimuth of the cross-beds and ripple-laminae and most probably correspond to the depressions between subaqueous dunes. Concavity ratio varies significantly within the excavation area. The degree of fragmentation of the bones and disarticulation of the skeletons suggest that the carcasses were reworked and slightly transported before burial. Sedimentological data suggest deposition in a shallow marine environment under the influence of rapid currents. The fossiliferous bed consists of a basal bone conglomerate covered by a cross-stratified sandstone with mud drapes, which is in turn overlain by ripple laminated sandstone, indicating the bones were buried by the gradual infilling of a tidal channel. All the Middle–Upper Devonian vertebrate bonebeds from Latvia are associated with sandy to clayey deposits and have been formed in a sea-coastal zone during rapid sedimentation episodes, but differ in fossil abundance and degree of preservation.

Lundsten, L., Schlining, K.L., Frasier, K., Johnson, S.B., Kuhnz, L.A., Harvey, J.B.J., Clague, G. & Clague, V.R.C. 2010: Timeseries analysis of six whale-fall communities in Monterey Canyon, California, USA. Deep-Sea Research I 57, 1573–1584.

Dead whale carcasses that sink to the deep seafloor introduce a massive pulse of energy capable of hosting dynamic communities of organisms in an otherwise food-limited environment. Through long- term observations of one natural and five implanted whale carcasses in Monterey Canyon, CA, this study suggests that: (1) depth and related physical conditions play a crucial role in species composition; (2) the majority of species in these communities are background deep-sea taxa; and (3) carcass degradation occurs sub-decadally. Remotely operated vehicles (ROVs) equipped with studio quality video cameras were used to survey whales during 0.8 to seven year periods, depending on the carcass. All organisms were identified to the lowest possible taxon. Community differences among whale-falls seemed to be most strongly related to depth and water temperature. The communities changed significantly from initial establishment shortly after a carcass’ arrival at the seafloor through multiple years of steady degradation. The majority of species found at the whale-falls were background taxa commonly seen in Monterey Bay. While populations of species characterized as bone specialists, seep restricted, and of unknown habitat affinities were also observed, sometimes in great abundance, they contributed minimally to overall species richness. All whale carcasses, shallow and deep, exhibited sub- decadal degradation and a time-series of mosaic images at the deepest whale site illustrates the rapidity at which the carcasses degrade.

McMullen, S.K., Holland, S.M., and O'Keefe, F.R. 2014. The occurrence of vertebrate and invertebrate fossils in a sequence stratigraphic context: the Jurassic Sundance Formation, Bighorn Basin, Wyoming, U.S.A. Palaios 29:277-294.

Previous studies of the sequence stratigraphic distribution of fossils have focused on the record of relatively abundant marine invertebrates. Only a handful of studies have examined how sequence stratigraphic architecture influences the occurrence of vertebrates, particularly large and rare tetrapods. The Jurassic Sundance Formation of the Bighorn Basin, Wyoming, USA, contains a rich suite of invertebrate and vertebrate fossils, including large and rare marine reptiles, and this allows the sequence stratigraphic controls on the distribution of these groups to be compared. The Sundance Formation consists of four depositional sequences, with the lower two being carbonate dominated and the upper two siliciclastic dominated. Two incised valley fills are also present. The presence of multiple depositional sequences and strongly erosional sequence boundaries is the likely cause of the complicated lithostratigraphic nomenclature of the Sundance. Invertebrates (mollusks and echinoderms) in the Sundance conform to well-established patterns of occurrences, including strong facies control and fossil concentrations at maximum flooding surfaces, in the upper portion of parasequences, and within lags overlying sequence boundaries. As expected from their rarity, marine reptiles (ichthyosaurs, plesiosaurs, and pliosaurs) show a weaker connection to sequence stratigraphic architecture. Nonetheless, they do display facies control and are found primarily in offshore mudstone, rather than shoreface and estuarine sandstone. They are also more common at hiatal surfaces, including a zone of concretions at the maximum flooding surface and in lag deposits overlying sequence boundaries. These associations suggest that sequence stratigraphic architecture may be a useful approach for discovery of marine vertebrates and that sequence stratigraphic context should be considered when making
paleobiological interpretations of marine vertebrates as well as invertebrates.

Monaco, P., Baldanza, A., Bizzari, R., Famiani, F., Lezzerini, M., and Sciuto, F. 2014. Ambergris cololites of Pleistocene sperm whales from central Italy and description of the new ichnogenus and ichnospecies Ambergrisichnus alleronae. Paleontologia Electronica 17.2.29A:1-20.

Ambergrisichnus alleronae igen. et isp. nov. from early Pleistocene clay marine deposits of Umbria, central Italy is here described, and attributed to cololites (evisceralites) of sperm whales. This interpretation is supported by the following characteristics that are frequently identified in modern ambergris including: internal organization of concentric structures, external shape with converging striae and bulges (rognons), and inclusions of squid beaks. These cololites were deposited in a relatively deep (100-150m) marine environment, and the large number of structures in a restricted area is plausibly ascribed to multiple death events of sperm whales. The description of A. alleronae igen. et isp. nov. is held by analysis of the taphonomic processes that took place after the sperm whale carcasses reached the seabed and led to fossilization. The analysis of benthic micro- and macrofauna found close to the studied structures provides supplementary data, which support the reconstruction of palaeoecological and palaeoenvironmental conditions comparable with those of the whale fall communities. This work increases knowledge of vertebrate coprolites. Moreover, this new information provides the data about the frequency of sperm whales in the Tyrrhenian Sea during the early Pleistocene, and raises new questions about the causes of this anomalous accumulation.

Obasi, C.C., Terry, D.O., Myer, G.H., and Grandstaff, D.E. 2011. Glauconite composition and morphology, shocked quartz, and the origin of the Cretaceous(?) main fossiliferous layer (MFL) in southern New Jersey, U.S.A. Journal of Sedimentary Research 81:479-494.

The Main Fossiliferous Layer (MFL) is a concentration of vertebrate and invertebrate fossils, 20 to 30 cm thick, preserved in a sequence of glauconitic sand at or near the Cretaceous–Paleogene boundary in the New Jersey (USA) coastal plain. Several hypotheses have been proposed to explain the origin and age of the MFL, including: marine transgression and formation of lag deposits of reworked bones and shells, formation of a condensed section and attritional accumulation of fossil material, and catastrophic collapse of Late Cretaceous ecosystems following the end-Cretaceous bolide impact at Chicxulub. We use new data on glauconite morphology, concentrations, geochemistry, and presence of shocked quartz, coupled with previous data on sedimentology, taphonomy, and rare-earth-element geochemistry of fossil vertebrates to interpret the genesis of the MFL. Glauconite concentration and maturity steadily increases from latest Cretaceous sediments of the Navesink–New Egypt Formation, through the MFL and into the Paleogene upper Hornerstown Formation, suggesting that marine transgression and decreasing sedimentation rates were a factor in the formation of the glauconite, but not the MFL. Rare earth-element patterns in fossil bones from the MFL, which are acquired during fossilization, are different from those of Cretaceous and Paleogene specimens, indicating that vertebrate remains in the MFL fossilized in situ and were not reworked from older, underlying units. Vertebrate fossils from the MFL are preserved as isolated to articulated specimens. While isolated specimens would be common in a transgressive lag, articulated specimens would not. Articulated specimens could be concentrated by attritional accumulation along a defined surface during a period of slow sedimentation, but the lack of a distinct increase in glauconite maturity or concentrations of elements associated with heavy-mineral accumulations at the Navesink–New Egypt–Hornerstown contact or MFL, which would be expected during a period of reduced sedimentation, hiatus, or unconformity, are absent at the localities studied. Shocked quartz was identified in a burrow fill directly beneath the MFL, at the contact of the Navesink and Hornerstown formations. Clay clasts with latest Cretaceous microfossils, along with reworked invertebrate fossils with infills of latest Cretaceous sediment, have been recovered from the MFL. The association of shocked quartz, mixture of isolated and articulated vertebrates with distinct rare-earth signatures, lack of a punctuated period of increased glauconite maturity, and presence of reworked Late Cretaceous invertebrates and clay clasts with Late Cretaceous microfossils suggests that the MFL may represent a thanatocoenosis that was the direct result of environmental disturbance associated with the end-Cretaceous impact event at Chicxulub.

Peltier, H., Dabin, W., Daniel, P., Van Canneyt, O., Doremus, G., Huon, M., and Ridoux, V. 2012. The significance of stranding data as indicators of cetacean populations at sea: modelling the drift of cetacean carcasses. Ecological Indicators 18: 278-290.

Stranded marine mammals are an important source of information and biological samples on cetacean population. Nevertheless, collecting stranding data remains opportunistic and its representativity must be improved, both qualitatively and quantitatively. Drifts of small cetaceans found by-caught in fishery observation projects and subsequently released dead with a numbered tag fitted to the tail fluke were predicted by using the Météo-France drift model MOTHY and allowed us to assess the proportion of dead dolphins recovered by volunteers of the French stranding network. Only 8% of dolphins were recovered ashore. The spatial representativity of strandings was assessed by performing back-calculation of car-cass drift with the same model in order to map the likely origin of stranded cetaceans. As a first step, external visual criteria of time-after-death (as a proxy to drift duration) were obtained from series of pho-tographs of dead small cetaceans maintained in a floating cage for 40 days and from tagged by-caught dolphins recovered stranded after a drift in real condition. Then, pictures of 242 stranded common dolphins (Delphinus delphis) were used to establish the average distribution of dolphin time-after-death in this area. Finally, 40 days-long reverse drifts of the 829 common dolphins recorded in the winter months of 2004–2009 were weighted by the modelled distribution of time-after-death in order to map the areas of likely origin. It appeared that most stranded common dolphins recorded along the French Atlantic coast originated from the continental shelf, mostly in the south of the Bay of Biscay. These results open new perspective on the use of stranding data and biological samples as sources of indicators in monitoring strategies.

Pyenson, N.D. 2010. Carcasses on the coastline: measuring the ecological fidelity of the cetacean stranding record in the eastern North Pacific Ocean. Paleobiology 36:453-480.

To understand how well fossil assemblages represent original communities, paleoecologists seek comparisons between death assemblages and their source communities. These comparisons have traditionally used nearshore, marine invertebrate assemblages for their logistical ease, high abundance, and comparable census data from living communities. For large marine vertebrates, like cetaceans, measuring their diversity in ocean ecosystems is difficult and expensive. Cetaceans,
however, often beach or strand themselves along the coast, and archived data on stranded cetaceans have been recorded, in some areas, over several decades. If the stranding record is interpreted as a death assemblage, then the stranding record may represent a viable alternative for measuring diversity in living communities on directly adjacent coastlines. This study assessed the fidelity of the cetacean stranding record in the eastern North Pacific Ocean. The living community in this region has
been studied for over 100 years and, recently, extensive and systematic live transect surveys using ship-based observing platforms have produced a valuable source of live diversity data. Over this same period, the U.S. Marine Mammal Stranding Program has collected and archived a record of cetacean strandings along the U.S. Pacific coastline, providing an ideal death assemblage for comparison. Using fidelity metrics commonly used in marine invertebrate taphonomy, I determined that the stranding record samples the living cetacean community with high fidelity, across fine and
coarse taxonomic ranks, and at large geographic scales (.1000 km of coastline). The stranding record is also richer than the live surveys, with live-dead ratios between 1.1 and 1.3. The stranding record recovers similar rank-order relative abundances as live surveys, with statistical significance. Also, I applied sample-based rarefaction methods to generate collector’s curves for strandings along the U.S. Pacific Coast to better evaluate the spatiotemporal characteristics of the stranding record. Results
indicate that saturation (i.e., sampling .95% assemblage) at species, genus, and family levels occurs in less than five years of sampling, with families accumulating faster than species, and larger geographic regions (i.e., longer coastlines) accumulating taxa the most rapidly. The high fidelity of the stranding record, measured both in richness and by ranked relative abundance, implies that ecological structure from living cetacean communities is recorded in the death assemblage, a finding that parallels marine invertebrate assemblages, though at far larger spatial scales. These results have implications for studying cetacean ecology in both modern and ancient environments: first, these results imply that the stranding record, over sufficiently long time intervals, yields a richer assemblage than using line transect methods, and faithfully records aspects of community structure; and second, these results imply that geochronologically well-constrained fossil cetacean assemblages might preserve ecologically relevant features of community structure, depending on depositional and taphonomic conditions.

Pyenson, N.D. 2011. The high fidelity of the cetacean stranding record: insights into measuring diversity by integrating taphonomy and macroecology. Proceedings of the Royal Society B 278:3608-3616.

Stranded cetaceans have long intrigued naturalists because their causation has escaped singular explanations. Regardless of cause, strandings also represent a sample of the living community, although their fidelity has rarely been quantified. Using commensurate stranding and sighting records compiled from archived datasets representing nearly every major ocean basin, I demonstrated that the cetacean stranding record faithfully reflects patterns of richness and relative abundance in living communities, especially for coastlines greater than 2000 km and latitudinal gradients greater than 48. Live–dead fidelity metrics from seven different countries indicated that strandings were almost always richer than live surveys; richness also increased with coastline length. Most death assemblages recorded the same ranked relative abundance as living communities, although this correlation decreased in strength and significance at coastline lengths greater than 15 000 km, highlighting the importance of sampling diversity at regional scales. Rarefaction analyses indicated that sampling greater than 10 years generally enhanced the completeness of death assemblages, although protracted temporal sampling did not substitute for sampling over longer coastlines or broader latitudes. Overall, this global live–dead comparison demonstrated that strandings almost always provided better diversity information about extant cetacean communities than live surveys; such archives are therefore relevant for macroecological and palaeobiological studies of cetacean community change through time.

Pyenson, N.D., Gutstein, C.S., Parham, J.F., Le roux, J.P., Chavarria, C.C., Little, H., Metallo, A., Rossi, V., Valenzuela-Toro, A.M., Velez-Juarbe, J., Santelli, C.M., Rubilar Rogers, D., Cozzuol, M.A., and Suarez, M.E. 2014. Repeated mass strandings of Miocene marine mammals from Atacama region of Chile point to sudden death at sea. Proceedings of the Royal Society B 281:20133316.

Marine mammal mass strandings have occurred for millions of years, but their origins defy singular explanations. Beyond human causes, mass strandings have been attributed to herding behaviour, large-scale oceanographic fronts and harmful algal blooms (HABs). Because algal toxins cause organ failure in marine mammals, HABs are the most common mass stranding agent with broad geographical and widespread taxonomic impact. Toxin-mediated mortalities in marine food webs have the potential to occur over geological timescales, but direct evidence for their antiquity has been lacking. Here, we describe an unusually dense accumulation of fossil marine vertebrates from Cerro Ballena, a Late Miocene locality in Atacama Region of Chile, preserving over 40 skeletons of rorqual whales, sperm whales, seals, aquatic sloths, walrus-whales and predatory bony fish.Marinemammal skeletons are distributed in four discrete horizons at the site, representing a recurring accumulation mechanism. Taphonomic analysis points to strong spatial focusing with a rapid death mechanism at sea, before being buried on a barrier-protected supratidal flat. In modern settings, HABs are the only known natural cause for such repeated, multispecies accumulations. This proposed agent suggests that upwelling zones elsewhere in the world should preserve fossil marine vertebrate accumulations in similar modes and densities.

Reisdorf, A.G., Bux, R., Wyler, D., Benecke, M., Klug, C., Maisch, M.W., Fornaro, P., and Wetzel, A. 2012. Float, explode, or sink: postmortem fate of lung-breathing marine vertebrates. Palaeobiodiversity and Palaeoenvironments 92:67-81.

What happens after the death of a marine tetrapod in seawater? Palaeontologists and neontologists have claimed that large lung-breathing marine tetrapods such as ichthyosaurs had a lower density than seawater, implying that their carcasses floated at the surface after death and sank subsequently after leakage of putrefaction gases (or ‘‘carcass explosions’’). Such explosions would thus account for the skeletal disarticulation observed frequently in the fossil record. We examined the taphonomy and sedimentary environment of numerous ichthyosaur skeletons and compared them to living marine tetrapods, principally cetaceans, and measured abdominal pressures in human carcasses. Our data and a review of the literature demonstrate that carcasses sink and do not explode (and spread skeletal elements). We argue that the normally slightly negatively buoyant carcasses of ichthyosaurs would have sunk to the sea floor and risen to the surface only when they remained in shallow water above a certain temperature and at a low scavenging rate. Once surfaced, prolonged floating may have occurred and a carcass have decomposed gradually. Our conclusions are of significance to the understanding of the inclusion of carcasses of lung-breathing vertebrates in marine nutrient recycling. The postmortem fate has essential implications for the interpretation of vertebrate fossil preservation (the existence of complete, disarticulated fossil skeletons is not explained by previous hypotheses), palaeobathymetry, the physiology of modern marine lung-breathing tetrapods and their conservation, and the recovery of human bodies from seawater.

Reisdorf, A.G., Anderson, G.S., Bell, L.S., Klug, C., Schmid-Rohl A., Jung, M., Wuttke, M., Maisch, Benecke, M., M.W., Wyler, D.,  Bux, R., Fornaro, P., and Wetzel, A. 2013. Reply to "Ichthyosaur embryos outside the mother body: not due to carcass explosion but to carcass implosion" by Van Loon (2013). Palaeobiodiversity and Palaeoenvironments 94:487-494.

No abstract.

Rouse, G.W., Goffredi, S.K., Johnson, S.B., Vrijenhoek, R.C. 2011. Not whale-fall specialists, Osedax worms also consume fishbones. Biology Letters 7:736-739.

Marine annelid worms of the genus Osedax exploit sunken vertebrate bones for food. To date, the named species occur on whale or other mammalian bones, and it is argued that Osedax is a whale-fall specialist. To assess whether extant Osedax species could obtain nutrition from non-mammalian resources, we deployed teleost bones and calcified shark cartilage at approximately 1000 m depth for five months. Although the evidence from shark cartilage was inconclusive, the teleost bones hosted three species of Osedax, each of which also lives off whalebones. This suggests that rather than
being a whale-fall specialist, Osedax has exploited and continues to exploit a variety of food sources. The ability of Osedax to colonize and to grow on fishbone lends credibility to a hypothesis that it might have split from its siboglinid relatives to assume the bone-eating lifestyle during the Cretaceous, well before the origin of marine mammals.

Sansom, R.S., Gabbott, S.E., and Purnell, M.A. 2010. Decay of vertebrate characters in hagfish and lamprey (Cyclostomata) and the implications fro the vertebrate fossil record. Proceedings of the Royal Society B 278:1150-1157.

The timing and sequence of events underlying the origin and early evolution of vertebrates remains poorly understood. The palaeontological evidence should shed light on these issues, but difficulties in interpretation of the non-biomineralized fossil record make this problematic. Here we present an experimental analysis of decay of vertebrate characters based on the extant jawless vertebrates (Lampetra and Myxine). This provides a framework for the interpretation of the anatomy of soft-bodied fossil vertebrates and putative cyclostomes, and a context for reading the fossil record of non-biomineralized vertebrate characters. Decay results in transformation and non-random loss of characters. In both lamprey and hagfish, different types of cartilage decay at different rates, resulting in taphonomic bias towards loss of ‘soft’ cartilages containing vertebrate-specific Col2a1 extracellular matrix proteins; phylogenetically informative soft-tissue characters decay before more plesiomorphic characters. As such, synapomorphic decay bias, previously recognized in early chordates, is more pervasive, and needs to be taken into account when interpreting the anatomy of any non-biomineralized fossil vertebrate, such as Haikouichthys, Mayomyzon and Hardistiella.

Sansom, R.S., Gabbott, S.E., and Purnell, M.A. 2010. Non-random decay of chordate  characters causes bias in fossil interpretation. Nature 463:797-800.

Exceptional preservation of soft-bodied Cambrian chordates provides our only direct information on the origin of vertebrates1,2. Fossil chordates from this interval offer crucial insights into how the distinctive body plan of vertebrates evolved, but reading this pre-biomineralization fossil record is fraught with difficulties, leading to controversial and contradictory interpretations3,4. The cause of these difficulties is taphonomic: we lack data on when and how important characters change as they decompose, resulting in a lack of constraint on anatomical interpretation and a failure to distinguish phylogenetic absence of characters from loss through decay3. Here we show, from experimental decay of Amphioxus and Ammocoetes, that loss of chordate characters during decay is non-random: the more phylogenetically informative are the most labile, whereas plesiomorphic characters are decay resistant. The taphonomic loss of synapomorphies and relatively higher preservation potential of chordate plesiomorphies will thus result in bias towards wrongly placing fossils on the chordate stem. Application of these data to Cathaymyrus (Cambrian period of China) and Metaspriggina (Cambrian period of Canada) highlights the difficulties: these fossils cannot be placed reliably in the chordate or vertebrate stem because they could represent the decayed remains of any non-biomineralized, total-group chordate. Preliminary data suggest that this decay filter also affects other groups of organisms and that ‘stem-ward slippage’ may be a widespread but currently unrecognized bias in our understanding of the early evolution of a number of phyla.

Stinnesbeck, W., Frey, E., Rivas, R., Perez, J.P., Cartes, M.R., Soto, C.S., and Lobos, P.Z. 2014. A lower Cretaceous ichthyosaur graveyard in deep marine slope channel deposits at Torres del Paine National Park, southern Chile. Geological Society of America Bulletin doi: 10.1130/B30964.1

Remnants of ophthalmosaurid ichthyosaurs recently discovered in the vicinity of the
Tyndall Glacier in the Torres del Paine National Park of southern Chile are extremely
abundant and well preserved. After three field campaigns to the area, a total of 46 articulated and virtually complete ichthyosaur specimens, both adults and juveniles, were tentatively assigned to four different species of Ophthalmosauridae. Preservation is excellent and occasionally includes soft tissue and embryos. The skeletons are associated with ammonites, belemnites, inoceramid bivalves, and fishes as well as numerous plant remains. The enormous concentration of ichthyosaurs is unique for Chile and South America and places the Tyndall locality among the prime fossil Lagerstätten for Early Cretaceous marine reptiles worldwide. The deposit is Early Cretaceous (Valanginian–Hauterivian) in age and forms part of a monotonous bathyal to abyssal sequence of the Late Jurassic to late Early Cretaceous Rocas Verdes back-arc basin. In this region, the Tyndall ichthyosaur population may have profited from cold upwelling currents that caused abundant life at the shelf edge including masses of belemnites and small fish, the preferred diet of ichthyosaurs. The abundance of almost completely articulated ichthyosaur skeletons in the Tyndall area suggests that some animals fell victim to episodic mass-mortality events caused by turbidity currents traveling downslope through a submarine canyon. They lost orientation, drowned, and were dragged into the deep sea by these turbulent high-energy gravity flows. Their bodies ended up in an oxygen-deficient basin environment where they were immediately embedded by the fine turbidite suspension fallout. The Tyndall ichthyosaur locality thus combines characteristics of both concentration and conservation Lagerstätten.

Strganac, C., Jacobs, L.L., Polcyn, M.J., Mateus, P., Myers, T.S., Salminen, J., May, S.R., Araujo, R., Ferguson, K.M., Goncalves, A.O., Morais, M.L., Schulp, A.S., and Silva Tavares, T. da. 2015. Geological setting and paleoecology of the Upper Cretaceous Bench 19 marine vertebrate bonebed at Bentiaba, Angola. Netherlands Journal of Geosciences 94:121-136.

The Bench 19 Bonebed at Bentiaba, Angola, is a unique concentration of marine vertebrates preserving six species of mosasaurs in sediments best correlated by magnetostratigraphy to chron C32n.1n between 71.4 and 71.64 Ma. The bonebed formed at a paleolatitude near 24°S, with an Atlantic width at that latitude approximating 2700 km, roughly half that of the current width. The locality lies on an uncharacteristically narrow continental shelf near transform faults that controlled the coastal outline of Africa in the formation of the South Atlantic Ocean. Biostratigraphic change through the Bentiaba section indicates that the accumulation occurred in an ecological time dimension within the 240 ky bin delimited by chron 32n.1n. The fauna occurs in a 10 m sand unit in the Mocuio Formation with bones and partial skeletons concentrated in, but not limited to, the basal 1–2 m. The sediment entombing the fossils is an immature feldspathic sand shown by detrital zircon ages to be derived from nearby granitic shield rocks. Specimens do not appear to have a strong preferred orientation and they are not concentrated in a strand line. Stable oxygen isotope analysis of associated bivalve shells indicates a water temperature of 18.5°C. The bonebed is clearly mixed with scattered dinosaur and pterosaur elements in amarine assemblage. Gut contents, scavenging marks and associated shed shark teeth in the Bench 19 Fauna indicate biological association and attrition due to feeding activities. The ecological diversity of mosasaur species is shown by tooth and body-size disparity and by d13C analysis of tooth enamel, which indicate a variety of foraging areas and dietary niches. The Bench 19 Fauna was formed in arid latitudes along a coastal desert similar to that of modern Namibia on a narrow, tectonically controlled continental shelf, in shallow waters below wave base. The area was used as a foraging ground for diverse species, including molluscivorus Globidens phosphaticus, small species expected near the coast, abundant Prognathodon kianda, which fed on other mosasaurs at Bench 19, and species that may have been transient and opportunistic feeders in the area.

Stringer, G.L., and King, L. 2012. Late Eocene shark coprolites from the Yazoo Clay in northeastern Louisiana. New Mexico Museum of Natural History and Science Bulletin 57: 275-309.

Systematic, long-term surface collecting of two sites in the marine sediments of the upper Eocene Yazoo Clay (34.3 Ma) in Caldwell Parish, Louisiana, has resulted in the procurement of nearly 1200 shark coprolites. A sample (n = 374 or approximately 30% of total) of the 1196 collected coprolites is described in detail based on length, width, weight, density, coloration, external features, internal features (when possible), and morphology. Two primary morphological types, spiral and scroll, were recognized. Approximately 98.01% of the coprolites were classified as either spiral (556 specimens) or scroll (617 specimens) based on external and internal morphological features. X-ray analysis showed the coprolites to be composed of moderately crystalline fluorapatite [Ca5(PO4)3F] with no compositional differences between the types. An annotated review of the literature dealing specifically with chondrichthyan coprolites was prepared. Prior studies at the sites produced extensive collections of shark teeth (> 2500) and provided statistical abundance data on the shark taxa. The shark tooth data, which provided occurrence and abundance, coupled with modern information on shark size, anatomy, and excretory characteristics allowed for a more specific identification of the shark coprolites as to possible source animals. The most likely source animals for the spiral coprolites were the lamniform Isurus praecursor and the carcharhiniform Abdounia enniskilleni, while the scroll coprolites were most likely produced by the carcharhiniform Carcharhinus gibbesi with the exception of several large specimens, which may be related to Galeocerdo alabamensis. Some of the coprolites had inclusions such as fish bones and scales that provided evidence of the dietary habits of the sharks. The extensive and longitudinal nature of this project has resulted in one of the most complete and exhaustive studies of late Eocene shark coprolites from the Gulf Coast.

Suan, G., Follmi, K.B., Adatte, T., Bomou, B., Spangenberg, J.E., and Van de Schootbrugge, B. 2012. Major environmental change and bonebed genesis prior to the Triassic-Jurassic mass extinction. Journal of the Geological Society, Lonon 169:191-200.

We present new geochemical and sedimentological data from marginal marine strata of Penarth Bay, south Wales (UK) to elucidate the origin of widespread but enigmatic concentrations of vertebrate hard parts (bonebeds) in marine successions of Rhaetian age (Late Triassic). Sedimentological evidence shows that the phosphatic constituents of the bonebeds were subjected to intense phosphatization in shallow current dominated settings and subsequently reworked and transported basinward by storms. Interbedded organic-rich strata deposited under quiescent and poorly oxygenated conditions record enhanced phosphorus regeneration from sedimentary organic matter into the water column and probably provided the main source of phosphate required for heavy bonebed clast phosphatization. The stratigraphically limited interval showing evidence for oxygen depletion and accelerated P-cycling coincides with a negative 4‰ organic carbon isotope excursion, which possibly reflects supra-regional changes in carbon cycling and clearly predates the ‘initial isotope excursion’ characterizing many Triassic–Jurassic boundary strata. Our data indicate that Rhaetian bonebeds are the lithological signature of profound, climatically driven changes in carbon cycling and redox conditions and support the idea of a multi-pulsed environmental crisis at the end of the Triassic, possibly linked to successive episodes of igneous activity in the Central Atlantic Magmatic Province.

Takukawa, Y. 2014. A dense occurrence of teeth of fossil "mako" shark ("Isurus" hastalis: Chondrichthyes, Lamniformes), associated with a balaenopterid-whale skeleton of the late Miocene Pisco Formation, Peru, South America. Bulletin of the Gunma Museum of Natural History 18:77-86.

Sixteen fossil shark teeth were found in close contact with a balaenopterid-whale skeleton of the Late Miocene Pisco Formation in Peru, South America. This whale skeleton (GMNH-PV 159) was excavated in Aguada de Lomas of western Arequipa in 1990, and exhibited in Gunma Museum of Natural History, Japan, after 1996. All teeth have relatively large and triangular shaped crowns. The cutting edge is smooth and almost straight in profile. Their roots are bulky and stout with long or expanded lobes. These characteristics indicate that all teeth are identified to fossil makoshark (“Isurushastalis). And the variety of the shape in each tooth implies difference of tooth position in its jaw. The duplication of the teeth at two positions (anterior tooth and intermediate tooth) and the difference of the crown size of anterior teeth suggest that the minimum number of shark individuals which had preyed on the whale is two. And one of them might be smaller than the other one. In addition, it is recognized that one of the sharks sank its upper lateral tooth into the whale skull bone.

Vasilkova, J., Luksevics, E., Stinkulis, G., and Zupins, I. Taphonomy of the vertebrate bonebeds from the Klunas fossil site, Upper Devonian Tervete Formation of Latvia. Estonian Journal of Earth Sciences 61:105-119.

Combined sedimentological and taphonomical study of the siliciclastic sequence of the Tērvete Formation in the stratotypical area was aimed at revealing the formation of the three oryctocoenoses discovered and related structural and textural features of the deposits, as well as at detailed observation of the taphonomical peculiarities of the obtained palaeontological material. The fossil vertebrate assemblage is represented by 14 taxa comprising placoderms, acanthodians, sarcopterygians and actinopterygians. The three oryctocoenoses, first recognized in 2010, differ in the proportions of repeatedly buried material, in the number and degree of preservation of small and fragile skeletal elements, as well as in the evaluated current velocity and the transportation distance. Sedimentary concentrations of marine vertebrate remains, dominated by the antiarchs Bothriolepis ornata and B. jani, have been formed under the influence of fluvial and tidal processes in the shallow-water environment, deltaic or estuarine settings. Elongated placoderm and sarcopterygian bones are probably better indicators of the palaeoflow direction than acanthodian spines or sarcopterygian teeth.

Vullo, R. 2011. Direct evidence of hybodont shark predation on late Jurassic ammonites. Naturwissenschaften 98:545-549.

Sharks are known to have been ammonoid predators, as indicated by analysis of bite marks or coprolite contents. However, body fossil associations attesting to this predator–prey relationship have never been described so far. Here, I report a unique finding from the Late Jurassic of western France: a complete specimen of the Kimmeridgian ammonite Orthaspidoceras bearing one tooth of the hybodont shark Planohybodus. Some possible tooth puncture marks are also observed. This is the first direct evidence of such a trophic link between these two major Mesozoic groups, allowing an accurate identification of both organisms. Although Planohybodus displays a tearing-type dentition generally assumed to have been especially adapted for large unshelled prey, our discovery clearly shows that this shark was also able to attack robust ammonites such as aspidoceratids. The direct evidence presented here provides new insights into the Mesozoic marine ecosystem food webs.

Wilson, G.D.F., Paterson, J.R., and Kear, B.P. 2011. Fossil isopods associated with a fish skeelton from the lower Cretaceous of Queensland, Australia - direct evidence of a scavenging lifestyle in Mesozoic Cymothoida. Palaeontology 54:1053-1068.

A dense assemblage of fossil isopod crustaceans (Brunnaega tomhurleyi Wilson, sp. nov.) from the Lower Cretaceous (Albian) Toolebuc Formation of Queensland, Australia, has been found within the carcass of a large actinopterygian fish, Pachyrhizodus marathonensis (Etheridge). Preservation of fine anatomical details supports referral to the genus Brunnaega Polz, which is herein reassigned to the family Cirolanidae. Furthermore, placement of this taxon within the cirolanid subfamily Conilerinae Kensley and Schotte is significant because the group includes modern species that are well known as voracious scavengers. This isopod–fish association represents the oldest unequivocal evidence of scavenging by Mesozoic cymothoidean isopods on a large vertebrate carcass.

Wretman, L., and Kear, B.P. 2013. Bite marks on an ichthyodectiform fish from Australia: possible evidence of trophic interaction in an early Cretaceous marine ecosystem. Alcheringa 38:170-176.

A well-preserved fish skull from late Albian deposits of the Allaru Mudstone near Richmond in Queensland displays a conspicuous V-shaped pattern of indentations, punctures and depression fractures consistent with a vertebrate bite trace. This is the first direct evidence of trophic interaction between vertebrates within an Early Cretaceous marine ecosystem from Australia. The specimen is taxonomically referable to the large bodied (ca 1m snout–tail length) ichthyodectiform Cooyoo australis, but the size and spacing of the tooth marks is incompatible with attack by a conspecific individual. The lack of osseous growths concordant with healing also suggests that the bite occurred shortly before or after the animal’s death. Comparison with the dentitions of other coeval vertebrates indicates compatible tooth arrangements in longirostrine amniote predators such as polycotylid plesiosaurians, ornithocheiroid pterosaurs and especially the ichthyosaurian  Platypterygius. The implications of this as a potential predator–prey association are that Early Cretaceous actinopterygians occupied middle-level trophic niches and were in turn consumed by higher-level amniote carnivores, similar to many extant marine vertebrate communities of today.

Zammit, M. and B. P. Kear. 2011. Healed bite marks on a Cretaceous ichthyosaur. Acta Palaeontologica Polonica, 56:859–863.

Reports of pathological ichthyosaur fossils are very rare. The identification of a series of healed cuts and an associated gouge on the lower jaw of an adult (ca. 5 metres body length) Platypterygius specimen from the Lower Cretaceous of Australia is therefore significant, because it constitutes direct evidence of bite force trauma sustained during the life of the animal. Based on the close spacing and nonlethal facial positioning of the wounds, they were probably not inflicted by a predator. Alternative explanations might include an accidental aggressive encounter with another large vertebrate, or perhaps an intraspecific interaction such as during courtship or combat over food, mates, or territory.

Zaton, M., and Rakocinski, M. 2014. Coprolite evidence for carnivorous predation in a Late Devonian pelagic environment of southern Laurussia. Palaeogeography, Palaeoclimatology, Palaeoecology 394:1-11.

Small, light-brown and beige cylindrical structures found in the lower Famennian (Upper Devonian) shales and marls of the Holy Cross Mountains area, central Poland, have been investigated for the first time. Their compact, pellet-shaped morphology and the presence of various fossil fragments scattered within the phosphatic groundmass clearly indicate that they are coprolites. The coprolite inclusions are dominated by arthropod cuticle fragments followed by fish remains, one conodont, and one scolecodont. The arthropod cuticle fragments are represented by the crustacean-like thylacocephalan Concavicaris and three other different types of arthropods of uncertain affinity. The presence of some conical fragments resembling telsons from phyllocarid crustaceans suggests that some of the cuticle fragments may belong to that group of arthropods. The fish remains mainly consist of actinopterygian paleoniscoid scales and sarcopterygian teeth. Taking both fossil and facies characteristics into account, it is clear that the coprolites originated from a carnivorous pelagic fishes that hunted other fishes and swimming arthropods. Surprisingly, similar faunal contents consisting of paleoniscoid fishes, Concavicaris arthropods, and conodonts occur in situ within the body cavities of the Famennian cladoselachian sharks in the Cleveland Shale, Ohio. Such a coincidence suggests that at least some of the Famennian coprolites from Poland may have also been produced by pelagic carnivorous sharks. The preservation of defecated remains was influenced by an interplay between an oxygen-deficient benthic environment devoid of bioturbators and scavengers and rapid, microbially-driven phosphatization.