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Faeces produced by marine vertebrates and macro-invertebrates contain sufficient organic matter to represent a usable food source for a wide array of macroscopic animals. In some extant marine environments, coprophagy even represents a crucial trophic interaction in food webs. In ancient ecosystems, coprophagy by macroscopic animals is occasionally exemplified by coprolites that exhibit biting traces or burrows. Here, we report Gnathichnus pentax on an exquisitely preserved vertebrate-bitten vertebrate coprolite from the marine calcareous deposits of the Pietra leccese (Miocene, southern Italy). This unusual occurrence is interpreted as evidence of the feeding activity of a regular echinoid; in particular, it may represent either exploratory coprophagy or the browsing of an algal (microbial) film that locally developed on the exterior of the faeces. Strengthening the former interpretation, the development of microbial communities on submerged faeces often leads to their destruction; furthermore, some extant Antarctic echinoderms are well known to ordinarily feed on vertebrate faeces, and coprophagy is believed to be fairly widespread among sea urchins. Supporting the algal browsing hypothesis, in turn, only a limited area of the external surface of the faeces was subject to grazing, and the resulting trace is neatly defined, which suggest that the feeding sea urchin targeted a precise location on the dung's exterior when the latter was already rather firm. To our knowledge, the G. pentax specimen studied here represents the first published record of this ichnotaxon on a coprolite.

An isolated and deformed lower tooth plate of an eagle ray (Aetomylaeus sp., Myliobatidae, Myliobatiformes) is reported herein from the Miocene deposits along Calvert Cliffs, Maryland, U.S.A. Deformed myliobatid tooth plates like this, either fossil or modern, are exceedingly rare. All medial teeth are deformed/skewed such that the right side of each tooth forms an angle of about 10 degrees to the transverse axis of the dental plate. The skewed abnormal form of the teeth in USNM PAL 726325 is not thought to be the result of modern or taphonomic deformation. Rather, the deformity exhibited by USNM PAL 726325 gives every indication that successive similarly deformed teeth came about as a result of a persistent anatomical deformity of the dental lamina. From the consistency in the deformed shape of each tooth, it would appear as though the dental lamina retained this anomalous shape at least throughout the time represented by the age of the tooth plate. If this interpretation is correct, the deformity was not fatal and did not significantly impair the functionality of the tooth pavement over a protracted part (or all) of the individual's life span.

An isolated Miocene baleen whale left radius was marked repeatedly by shark bite-shake traces. The radius probably derives from the Plum Point Member of the Calvert Formation, Calvert Cliffs, Calvert County, Maryland, U.S.A. At least three successive bite-shake traces, made by multiple teeth, marking the radius are attributed to the trace fossil Linichnus bromleyi. These bite-shake trace consisting of shallow, thin arching gouges on a radius, likely indicates scavenging rather than active predation. The most likely means of producing the bundle of L. bromleyi within each of the three sets of traces would be through repeated biting as the shark re-positioned the prey in its mouth or, perhaps, by a shark species with multiple functional teeth within its tooth row. If the bite traces were produced by a non-serrated tooth (as they appear to have been), then the most likely candidate would be Carcharodon hastalis.

To date, for the family Phocidae, only two fossil genera of the subfamily Monachinae (Monotherium and Terranectes) and two fossil genera of the subfamily Phocinae (Prophoca and Leptophoca) have bee...

The highly fossiliferous St. Marys Formation is exposed along Calvert Cliffs, Maryland, and comprises one of the best available records of late Miocene life in the northeastern United States. Rachycentron stremphaencus new species, a cobia from the late Miocene (Tortonian) of the St. Marys Formation is described herein on the basis of a single three-dimensional neurocranium. This fossil represents the earliest known occurrence of neurocranial remains of the genus Rachycentron in the record. Rachycentron stremphaencus differs from Rachycentron canadum (Linnaeus, 1766) in many ways. The most obvious include a different ornamentation of the outer surface of the cranial bones; a notably pronounced lateral ridge resulting in a considerable gradient from the dorsal-medial exposure of the frontal to its lateralmost supraorbital margin; the size, shape, and position of the sphenotic that is located in the posterior half of the neurocranium and its lateralmost edge being adjacent to the anteriormost extent of the wedge-shaped trough in the dorsal surface of the skull formed by the lateral and medial ridges; the two contralateral medial ridges forming a proportionately much wider trough on either side of the supraoccipital; the epioccipitals not reaching the rear edge of the neurocranium; and the lack of a conspicuous posterolateral prong of the intercalar.UUID: http://zoobank.org/c8523bb4-2de2-4318-9a37-027f463a0441

In the case study presented here, we describe a Miocene aetobatid, Aetobatus arcuatus Agassiz, 1843 lower tooth plate that exhibits a longitudinal furrow lesion. Hitherto in the literature, patholo...

The last comprehensive review of the fossil vertebrates from the Miocene of Calvert Cliffs was published more than 100 years ago. This volume is a collection of papers that updates some of the geological features of Calvert Cliffs and provides reviews of the fossil biota that include representatives from the following taxonomic groups: chondrichthyans (chimaeras, shark, skates, and rays), actinopterygians (ray-finned fishes), crocodilians (crocodiles), and sirenians (sea cows). Peter Vogt, Ralph E. Eshelman, and Stephen J. Godfrey document how the 20–40 m [65–130 ft] high Calvert Cliffs along the western shore of the Chesapeake Bay continue to yield insights into 18–8 mya (Miocene) geology, marine and terrestrial vertebrate fauna, and the origin and evolution of Chesapeake Bay and Calvert Cliffs up to the present. These exposures rank high among the best-known fossiliferous deposits of any age. Bretton W. Kent describes the cartilaginous fish (the chondrichthyan) fauna, consisting of 54 species—3 chimaeras (ratfishes), 39 sharks, and 12 skates and rays—a fauna rich in large macrophagous sharks and large neritic rays. In an addendum to Kent’s chapter, he and David J. Ward describe a new species of giant thresher shark with serrated teeth. Giorgio Carnevale and Stephen J. Godfrey present an account of the 38 actinopterygian taxa known from osteological remains and a diverse otolith assemblage of at least 55 taxa. These actinopterygians show an affinity for well-oxygenated muddy and sandy substrates dominated primarily by shallow-water species characteristic of the inner shelf and secondarily by epipelagic taxa. Robert E. Weems details the crocodilians referable to the tomistomine Thecachampsa. The closest living relative is Tomistoma schlegelii, the false gharial of Southeast Asia. Two species are present: Thecachampsa sericodon and T. antiquus. These tomistomines are found in shallow marine coastal deposits, indicating that they inhabited coastal waters. Daryl P. Domning reports that fossils of the Miocene marine fauna include rare sirenians of the family Dugongidae. Three taxa are known: the halitheriine dugongid Metaxytherium crataegense, the dugongine dugongid Nanosiren sp., and another dugongine, aff. Corystosiren. The St. Marys Formation contains remains that may be referable to Metaxytherium floridanum, but confirmation awaits the discovery of more complete specimens.

A description and analysis is given of three Neogene odontocete caudal vertebrae that were bitten by the extinct megatooth sharks Carcharocles megalodon or Carcharocles chubutensis. The peduncular caudal vertebrae show bilateral gouge marks consistent with having been actively bitten and wedged between adjacent teeth of C. megalodon or C. chubutensis. None of the vertebrae show signs of healing. The occurrence of bite marks on distal caudals suggests active predation (vs. scavenging) in order to immobilize even relatively small prey prior to consumption.

Coprolites (fossilized feces) can preserve a wide range of biogenic components. A mold of a hatchling turtle partial shell (carapace) referable to Taphrosphys sulcatus is here identified wi...

The holotype partial skull ofAgorophius pygmaeus(the monotypic form for both the genusAgorophiusand the Family Agorophiidae) has been missing for approximately 140 years. Since the discovery ofAgorophius pygmaeus, many additional taxa and specimens have been placed in the Family Agorophiidae, only to be reclassified and removed later. This has created confusion as to what is and what is not an agorophiid and a lack of clarity as to what characteristics delimit the Agorophiidae. A newly discovered skull of an agorophiid recently collected from an underwater cliff face of the Ashley River, South Carolina, USA, is assigned toAgorophius pygmaeus. It derives from the base of the Ashley Formation (early Oligocene). The new specimen consists of most of the skull and periotics, which are well preserved and described for the first time in an agorophiid. The new specimen provides an opportunity to diagnose the Agorophiidae and place the genus and species within the phylogenetic context of the early odontocete radiation in the Oligocene, along with other taxa such as the Ashleycetidae, Mirocetidae, Patriocetidae, Simocetidae, Waipatiidae, and Xenorophidae. Based on this new understanding, Agorophiidae are known with certainty only from the early Oligocene of South Carolina, with other undescribed, potential agorophiid specimens from the Oligocene of the North Pacific region (Japan, Mexico, and Washington State).

Coprolites can preserve a wide range of biogenic components. Of all the coprolites known from the fossil record, hitherto only two are known to preserve vertebrate tooth impressions (i.e., those of chondrichthyans). Here, a coprolite, from a thick lag deposit that includes a mixture of late Cretaceous, early Paleocene, and Plio-Pleistocene taxa at Clapp Creek in Kingstree, Williamsburg County, South Carolina, USA, preserves bite marks most consistent with having been made by a gar, Lepisosteus sp. (Lepisosteidae, Actinopterygii). This is the first-known coprolite to preserve actinopterygian tooth/bite marks. Aborted coprophagy seems unlikely; an accidental or serendipitous strike more likely describes the origin of the score marks over the surface of the coprolite. This coprolite also preserves small paired striations interpreted as evidence of coprophagy by an unknown organism.

A newly discovered assemblage of predominantly small tracks from the Cretaceous Patuxent Formation at NASA’s Goddard Space Flight Center, Maryland, reveals one of the highest track densities and diversities ever reported (~70 tracks, representing at least eight morphotypes from an area of only ~2 m2). The assemblage is dominated by small mammal tracks including the new ichnotxon Sederipes goddardensis, indicating sitting postures. Small crow-sized theropod trackways, the first from this unit, indicate social trackmakers and suggest slow-paced foraging behavior. Tracks of pterosaurs, and other small vertebrates suggest activity on an organic-rich substrate. Large well-preserved sauropod and nodosaurs tracks indicate the presence of large dinosaurs. The Patuxent Formation together with the recently reported Angolan assemblage comprise the world’s two largest Mesozoic mammal footprint assemblages. The high density of footprint registration at the NASA site indicates special preservational and taphonomic conditions. These include early, penecontemporaneous deposition of siderite in organic rich, reducing wetland settings where even the flesh of body fossils can be mummified. Thus, the track-rich ironstone substrates of the Patuxent Formation, appear to preserve a unique vertebrate ichnofacies, with associated, exceptionally-preserved body fossil remains for which there are currently no other similar examples preserved in the fossil record.

This paper redescribes the holotype skull of the aristonectine elasmosaur Morturneria seymourensis from the upper Maastrichtian of Seymour Island, Antarctica. This description supports the validity of the genus Morturneria, distinct from the genus Aristonectes from Chile and Argentina. The paroccipital process of Morturneria is plesiomorphic, similar to Alexandronectes and unlike the autapomorphic occiput of Aristonectes. The palate of Morturneria is autapomorphic in possessing a strongly developed midline keel. The cranium of Morturneria is about 60% complete and preserves the anterior skull roof and palate; both regions were previously unknown in any aristonectine. The combination of the Morturneria holotype and recent research on other aristonectines allows the first confident cranial reconstruction of an aristonectine elasmosaur. The cranial anatomy of both Morturneria and its close relatives is derived relative to all other plesiosaurs, possessing a novel suite of dental and oral cavity adaptions. The suspensorium extends far behind the occipital condyle, and the jaw is long and hoop-like; together these features allowed a large gape and oral cavity volume. The palate of Morturneria is strongly keeled, forming arched lateral oral chambers that further increased oral cavity volume. The dentition of Morturneria is similar to that of Aristonectes, and all share autapomorphic interlocking combs of needle-like teeth that occluded outside the mouth and did not meet tip to tip. The upper and lower dentition formed an oral battery that may have functioned like a sieve in straining food particles from substrate ejected from the oral cavity. We theorize that this highly derived suite of adaptations is convergent with extant gray whales and archaic mysticetes and hypothesize that it functioned similarly in sieve feeding following suction. This is the first identification of whale-like filter feeding in any marine reptile, a condition once claimed to be anatomically impossible. Citation for this article: O'Keefe, F. R., R. A. Otero, S. Soto-Acuña, J. P. O'Gorman, S. J. Godfrey, and S. Chatterjee. 2017. Cranial anatomy of Morturneria seymourensis from Antarctica, and the evolution of filter feeding in plesiosaurs of the Austral Late Cretaceous. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1347570. Fil: O'Keefe, F. Robin. Marshall University; Estados Unidos Fil: Otero, Rodrigo A.. Universidad de Chile; Chile Fil: Soto-Acuña, Sergio. Museo Nacional de Historia Natural Chile; Chile Fil: O'gorman, Jose Patricio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentina Fil: Godfrey, Stephen J.. Calvert Marine Museum; Estados Unidos Fil: Chatterjee, Sankar. Museum of Texas Tech University; Estados Unidos

The spectacularly fossiliferous Calvert Formation is largely exposed in Maryland and Virginia and comprises the best available record of middle Miocene life in the northeastern United States. Lopho...

Most extant odontocetes appear to be anosmatic. However, some Miocene odontocetes, including a broken skull attributed to Squalodon sp. (Calvert Formation, Calvert Cliffs, Maryland, USA) preserve the osteological components associated with a well-developed sense of smell: dorsal nasal meatuses, ethmoturbinates within olfactory recesses, a perforate cribriform plate, and an olfactory bulb chamber. In Squalodon sp., the area within the olfactory recesses (i.e., covered in life by olfactory sensory epithelia) is 5367 mm 2 and the area occupied by the olfactory bulbs (i.e., the ethmoid area) is 769.8 mm 2 . In most mammals, the area of the olfactory epithelium is typically circa 16 times larger than the ethmoid area. The area covered by olfactory epithelium in CMM-V-2287 is only about seven times larger than its ethmoid area, less than half the area in typical mammals. During the Miocene, most odontocetes variously lost the osteological proxies indicative of osmatic ability. Perhaps biosonar surpassed the efficiency of olfactory cues during predation and social/parental/sexual interactions rendering the latter redundant/obsolete in odontocete analysis of, and interactions with and within their aquatic environments.

Belone is distinguished from other genera of Belonidae mostly because of its complete cephalic sensory system, presence of gill rakers, vomerine teeth, and the pattern of its dentition. This eastern North Atlantic genus contains two extant species and at least three described fossil species from Lower Oligocene and Upper Miocene formations in Europe. †Belone countermani, sp. nov., a new species of needlefish from the Tortonian Upper Miocene St. Marys Formation of Calvert Cliffs (Maryland, U.S.A.), is described herein based on a well-preserved three-dimensional associated pair of upper and lower jaws. This rostrum represents the only record of this genus in the western North Atlantic Ocean. †Belone countermani is characterized by a unique dental pattern on the dentary. The dentary commissural region is filled with several rows of small accessory teeth (five to seven) that gradually decrease in number of rows; along the symphysial region there is one inner row of conical teeth and one external row ...

The structure of the olfactory apparatus is not well known in both archaic and extant whales; the result of poor preservation in most fossils and locational isolation deep within the skulls in both fossil and Recent taxa. Several specimens now shed additional light on the subject. A partial skull of an archaic cetacean is reported from the Pamunkey River, Virginia, USA. The specimen probably derives from the upper middle Eocene (Piney Point Formation) and is tentatively assigned to the Protocetidae. Uncrushed cranial cavities associated with the olfactory apparatus were devoid of sediment. CT scans clearly reveal the dorsal nasal meatus, ethmoturbinates within the olfactory recess, the cribriform plate, the area occupied by the olfactory bulbs, and the olfactory nerve tract. Several sectioned skulls of the minke whale (Balaenoptera acutorostrata) were also examined, and olfactory structures are remarkably similar to those observed in the fossil skull from the Pamunkey River. One important difference between the two is that the fossil specimen has an elongate olfactory nerve tract. The more forward position of the external nares in extant balaenopterids when compared with those of extant odontocetes is interpreted to be the result of the need to retain a functional olfactory apparatus and the forward position of the supraoccipital/cranial vertex. An increase in the distance between the occipital condyles and the vertex in balaenopterids enhances the mechanical advantage of the epaxial musculature that inserts on the occiput, a specialization that likely stabilizes the head of these enormous mammals during lunge feeding.

A new genus and species of extinct inioid odontocete (Meherrinia isoni) is based on nine partial crania that probably originated from the late Miocene marine Eastover Formation in North Carolina, U.S.A. They were collected from the riverbed of the Meherrin River, a tributary of the Chowan River. Ossification of the mesethmoid and the tight inter-digitation of many sutures indicate that these specimens represent mature individuals. Key characteristics of the new inioid include maxillae that ‘squeeze’ the nasals into a slight hourglass shape and supraoccipital that is deeply wedged between the frontals and maxillae on the vertex. As compared to the extant iniid Inia geoffrensis (Amazon River dolphin) and the extant pontoporiid Pontoporia blainvillei (La Plata dolphin), Meherrinia is more plesiomorphic in having less elevated premaxillary eminences and supraorbital processes. In other respects Meherrinia is intermediate in morphology between the two extant genera of inioids. For example, the essenti...

Fishes of the genus Astroscopus are anatomically distinctive within the family Uranoscopidae, mostly because they are characterized by internal nares and are the only marine teleosts known to possess electric organs derived from extraocular muscles. The new world genus Astroscopus contains three extant species from tropical to temperate coastal waters of both sides of the American continent, plus fragmented isolated bones and otoliths of an indeterminate fossil species from the Pliocene and Pleistocene of the Coastal Plain of the eastern United States. Astroscopus countermani, sp. nov., a new stargazer from the Miocene (Tortonian) of Calvert Cliffs (Maryland), is described herein based on well-preserved three-dimensional cranial remains. These cranial remains represent the earliest known skeletal record for the family Uranoscopidae, as well as the earliest occurrence of the genus Astroscopus in the fossil record. Astroscopus countermani is typified by a unique neurocranial appearence, an oblitera...

Represented by a nearly complete cranium with associated mandible, teeth, and vertebrae, Yaquinacetus meadi is a new genus and species of archaic homodont odontocete from the latest Oligoce...

The teeth of two megatooth macro-predatory shark species (Carcharocles chubutensis and Carcharocles megalodon; Otodontidae, Chondrichthyes) occur within the Miocene Chesapeake Group of Mary...

More than 600 species have been identified from Calvert Cliffs, Calvert County, Maryland, U.S.A. The vast majority of these marine species are now extinct. This diverse biota consists of diatoms, d...

There is little osteological evidence of non-lethal predation events in the archaeological or vertebrate paleontological record. A small section of Pliocene cetacean rib collected from the Yorktown Formation within the PCS Phosphate Mine (formerly Lee Creek Mine), Aurora, North Carolina, U.S.A., shows evidence of this kind of trophic interaction. In this case study, we offer a diagnosis of bone traumatic pathology in which three bone-forming lesions on the partial rib are interpreted as the reaction to a bite inflicted by a macro-predator, the first such report from a marine environment. In addition to the three well-defined lesions, a thin layer of woven bone covers much of the remaining cortical bone. The combination of the three bone-forming lesions and the thin layer of woven bone suggest the presence of an inflammatory process almost certainly caused by infection secondary to the trauma. Survival following the traumatic event was probably less than 6 weeks. The Neogene chondrichthyan fauna from this locality preserves several large predators, including Carcharocles megalodon, Carcharodon carcharias, Isurus xiphidon and Parotodus benedeni, which were all capable, at least in terms of their size, of having bitten the cetacean. Although most of the odontocetes known from the Yorktown Formation were too small to have inflicted this wound, some of the physeterids may have been large enough to have caused the lesions on the partial rib. This evidence of predation in Pliocene whale bone raises the possibility of similar lesions being found in whale bone recovered from archaeological sites. Copyright © 2010 John Wiley & Sons, Ltd.

Eight Miocene odontocete partial rostra (six specimens from the Chesapeake Group of Maryland, one from the Chesapeake Group of Virginia, and another from the Hawthorn Group of Florida) exhibit periostitis, of unknown etiology, characterized by proliferative bone growth. Periostitis is an inflammation of the periosteum secondary to a predisposing event such as a fracture or infection. Computed tomography reveals that the lesions are limited to the premaxillae and that they became progressively swollen and gnarled as evidenced by the onion-like layering within the deformity. The level of maturity and degree of organization of the periostitis indicates that it likely developed over a period of months or years in these individuals. Given this length of time, these pathologies seem not to have been life-threatening despite the gross size and shape of most of these periosteal reactions. The fossils range in age from about 11 to 15 million yr and all eight rostra appear to be derived from the same, but as yet unnamed or unrecognized species of odontocete. The family from which these odontocetes derive remains unknown. Un-deformed rostra attributed to this species have not been identified, which opens the possibility that “abnormal” was the new normal for this species of odontocete.

Shark teeth are the most common vertebrate fossils found along the western shore of Chesapeake Bay at Calvert Cliffs in Maryland. The stratigraphic distribution of teeth within the cliffs has not yet been documented. We utilized museum collections of in situ teeth to access their distribution within stratigraphic beds and a large selection of float teeth retrieved from Calvert County beaches as a proxy for the distribution of teeth within stratigraphic beds and across underlying beaches. Museum collections provide 1,866 teeth recorded in situ; float collections yield a total of 24,409 teeth. These data sets offer different, but complementary, results. Miocene sediments along Calvert Cliffs comprise the Calvert, Choptank, and St. Marys formations. Over 96% of all teeth in the in situ data set derive from the Calvert Formation, likely due to favorable paleoenvironmental conditions for sharks. The non-uniform stratigraphic distribution of teeth is further supported by an uneven distribution of teeth...

The vast majority of the more than 600 species that have been identified from the Miocene sediments of Calvert Cliffs, Maryland (Fig. 1), are of marine organisms. The biota includes palynomorphs, terrestrial plants, diatoms, dinoflagellates, foraminiferans, sponges, annelid worms, corals, abundant and diverse mollusks, ostracods, decapod crustaceans, barnacles, an inarticulate brachiopod, echinoderms, sharks and rays, bony fishes, turtles, crocodiles, pelagic birds, seals, sea cows, isolated and fragmentary remains of large terrestrial mammals, and a diverse assemblage of approximately 30 species of both odontocetes and mysticetes (Gottfried et al., 1994). In terms of vertebrate remains, those of cetaceans are second only to the number of chondrichthian teeth that erode from the length of Calvert Cliffs and their extensions out under the waters of the Chesapeake Bay. The three Miocene formations comprising Calvert Cliffs (Fig. 2) differ in their cetacean assemblages. The Lower Miocene to lower Middle Miocene (Burdigalian and Langhian) Calvert Formation has long been known to preserve one of the world's richest and most diverse extinct cetacean assemblages. Of the 19 recognized odontocete species from the Chesapeake Group, 12 are known exclusively from the Calvert Formation and another three are derived from both the Calvert and the Middle Miocene (Serravallian) Choptank formations (to date, no odontocete spe

A siderite concretion from the Middle Pennsylvanian, Francis Creek Shale (Carbondale Formation, Desmoinesian Series, Westphalian C), in the Mazon Creek area, Will–Kankakee counties, Illinois, U.S.A., preserves a hitherto unknown temnospondyl amphibian. The natural mold of the dorsoventrally compressed skeleton (total preserved length of the larva is 38.5 mm (~1.5 inches)), includes a proportionately large skull, hyobranchial denticles, ossified portions of the axial skeleton, elements of both the pectoral and pelvic limbs, and endocasts of segments of the digestive system. Differential staining of the entombing matrix outlines gill filaments, portions of the body wall, and apparently most of the length of the tail. Although this single specimen probably represents a new taxon, too few diagnostic characters are displayed by the larva to name a new species. Large interpterygoid vacuities support its inclusion in the Temnospondyli. Vomers contributing to the formation of the anterior margin of these vacuities place this taxon above the edopoid grade of organization. Furthermore, a very wide cultriform process of the parasphenoid places this taxon above dendrerpetontids. Specific characters that would ally this taxon with any known family have not been identified.

On the basis of an assigned specimen (USNM 526604, from the Plum Point Member of the Calvert Formation, Early Miocene, Maryland, U.S.A.), Araeodelphis natator Kellogg, 1957, is referred to the Platanistidae. A phylogenetic analysis identifies A. natator as the most stemward member of the family. By contrast, the extant river dolphin, Platanista gangetica (Platanistidae), is one of the most specialized odontocetes. Araeodelphis natator exhibits the following unique combination of characters: overall skull length (condylobasal length) estimated at about 50 cm; rostrum twice the length of the facial region; rostrum wider than deep throughout its entire length; approximately 50 teeth in each quadrant of rostrum; mesorostral canal closed dorsally through anterior half of rostrum by apposition of contralateral premaxillae; cranium with elevated orbits directed anterolaterally; maxillary crest (supraorbital process of frontal and overlapping maxilla) modestly thickened laterally and elevated above midlin...

The ceratopsid dinosaur genus Chasmosaurus from the Judith River Formation (Campanian; Judithian) of western Canada shows considerable variability in cranial morphology due in part to an unusually long ontogenetic trajectory. Nevertheless, two more or less distinct morphs can be identified. Allometry and sexual dimorphism cannot be invoked to account for this variability, leaving the presence of two species as the most likely explanation. In C. belli, the posterior margin of the parietal frill shows little or no emargination and bears one large triangular epoccipital on each posterolateral corner. Additional epoccipitals may be present, but are much less prominent. Chasmosaurus Canadensis, Chasmosaurus kaiseni, and Chasmosaurus brevirostris also show this morphology, and are here considered junior synonyms of Chasmosaurus belli. Chasmosaurus russelli is characterized by a deeply emarginated posterior parietal margin. On each side, the posterior margin of the frill forms a broad arch, bearing thre...

Isolated amphibian bones are preserved in freshwater sediments of the Namurian A Pomquet Formation near Grand Étang, Nova Scotia. This assemblage resembles other late Mississippian lakebed or estuarine faunas in that most of the remains can be confidently attributed to one or more taxa of embolomere (order Anthracosauria) or to the order Colosteoidea, although they are indeterminate at the level of genus and species. However, a number of tetrapod elements of uncertain affinities suggests a much more diverse fauna.

Nine siderite concretions from the Middle Pennsylvanian, Francis Creek Shale (Carbondale Formation, Desmoinesian Series, West‐phalian C‐D), in the Mazon Creek area, Will‐Kankakee Counties, Illinois, U.S.A. preserve clusters of impressions of small eggs. Differential staining of the matrix suggests that the eggs were originally spawn within gelatinous strings containing 1 or 2 rows of eggs. Unfortunately, these egg impressions lack the diagnostic features needed to identify the zoological taxon (taxa) from which they originated.

The structure of the olfactory apparatus is not well known in both archaic and extant whales; the result of poor preservation in most fossils and locational isolation deep within the skulls in both fossil and Recent taxa. Several specimens now shed additional light on the subject. A partial skull of an archaic cetacean is reported from the Pamunkey River, Virginia, USA. The specimen probably derives from the upper middle Eocene (Piney Point Formation) and is tentatively assigned to the Protocetidae. Uncrushed cranial cavities associated with the olfactory apparatus were devoid of sediment. CT scans clearly reveal the dorsal nasal meatus, ethmoturbinates within the olfactory recess, the cribriform plate, the area occupied by the olfactory bulbs, and the olfactory nerve tract. Several sectioned skulls of the minke whale (Balaenoptera acutorostrata) were also examined, and olfactory structures are remarkably similar to those observed in the fossil skull from the Pamunkey River. One important difference between the two is that the fossil specimen has an elongate olfactory nerve tract. The more forward position of the external nares in extant balaenopterids when compared with those of extant odontocetes is interpreted to be the result of the need to retain a functional olfactory apparatus and the forward position of the supraoccipital/cranial vertex. An increase in the distance between the occipital condyles and the vertex in balaenopterids enhances the mechanical advantage of the epaxial musculature that inserts on the occiput, a specialization that likely stabilizes the head of these enormous mammals during lunge feeding.

New specimens of caenagnathid theropods are described from the Judith River Formation (Campanian) of southern Alberta, the Hell Creek Formation (Maastrichtian) of South Dakota, and the Bissekty Formation (Turonian) of Uzbekistan. With the exception of the Hell Creek specimen, and a vertebra from Alberta, all are from the symphysial regions of the lower jaws. Caenagnathids are rare and poorly known animals, and the described fossils preserve heretofore unknown features, including vascular grooves and foramina in the symphysial region, and the pattern of overlapping sutures between jaw elements. Most of the new specimens are different from the holotype of Caenagnathus collinsi Sternberg and may represent the second described species, Caenagnathus sternbergi. The two jaws from the Bissekty Formation are the first oviraptorosaurian jaws described from Uzbekistan and represent a new genus and species anatomically closer to Caenagnathus than to central Asian forms like Oviraptor, Conchoraptor and Ingenia. There are at least five characters that distinguish caenagnathid and oviraptorid jaws, but it is concluded that the length of the symphysial region must be used with caution. Jaw anatomy supports the idea that oviraptorids were well adapted for eating eggs, although their diet was probably not restricted to one food type.

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.

Two recently discovered specimens of a medium-sized embolomerous amphibian contribute to our knowledge of the vertebrate fauna of Joggins, Nova Scotia (Cumberland Group; Pennsylvanian, Westphalian B). One specimen comprises a series of vertebrae from the sacral and proximal caudal regions, left ilium, and portions of the left hind limb, and the other includes an articulated series of nine posterior trunk vertebrae and associated ribs, most of the hind limb, and gastralia. It is unique among embolomeres in possessing both complete, disc-shaped intercentra and dorsally open, crescentic intercentra in a single presacrai vertebral series. Both are interpreted as larger individuals of Calligenethlon watsoni, an embolomere once believed to be characterized by small adult size. These specimens pertain to the largest tetrapod recovered to date from an upright lycopod stump at Joggins.

Xiphisternal elements of dinosaurs are only rarely recovered, probably because they seldom ossified and those that did were fragile and easily destroyed. An isolated but relatively complete, right xiphisternal element was collected from the Dinosaur Park Formation of Dinosaur Provincial Park, Alberta. It apparently contacted the left xiphisternal, the sternum, and at least three costal cartilages. Similar in overall morphology to xiphisternals of Edmontonia, Nodosaurus, and Panoplosaurus, it can be referred to the ankylosaur family Nodosauridae.

Ref : Canadian Journal of Earth Sciences, 40 (4): 507–514. Part of a line of text is missing in the printed text of the Acknowledgments. The second paragraph of the Acknowledgments should read I would also like to express my sincerest thanks …