This paper describes a new species of lungfish, Ptychoceratodus roemeri, sp. nov., based on 25 tooth plates from the Upper Triassic (Carnian) freshwater sediments of the Krasiejów locality, in Poland. Two vomerine teeth and numerous scales were also found associated with the tooth plates. Specific variations in Ptychoceratodus tooth plates are analyzed together with morphological evidence of ontogenetic changes among selected species. This study permits the discrimination between diagnostic, systematic characters and those affected by ontogeny. The new species together with nine other ptychoceratodonts from the Triassic of Europe are compared in order to assess their interrelationships. On the basis of morphological and biometrical comparisons, P. roemeri, sp. nov., is most closely related to P. concinnus from the Lehrberg Beds in Germany.

New remains of the early Eocene hyaenodontid Indohyaenodon raoi are described from the Vastan Lignite Mine in Gujarat, western India, including the first known rostrum, upper dentition, and postcrania, substantially expanding our knowledge of the species and providing insights into its functional morphology and relationships. Craniodental morphology suggests that I. raoi had a broad diet, including non-vertebrate material as well as flesh of a diversity of prey species. Postcranial morphology is broadly similar to that of other early hyaenodontids and suggests a scansorial locomotor repertoire. Dental morphology indicates that I. raoi is closely related to other South Asian hyaenodontids, with shared features including strong cingula, narrow premolars, and a reduced P4 protocone. We present the most comprehensive phylogenetic analysis of Hyaenodontidae to date, which corroborates this relationship but finds South Asian hyaenodontids to be the stem of a group that includes most African hyaenodontids. This and other higher-level relationships within Hyaenodontidae are, however, weakly supported, and substantially different alternative hypotheses of relationships are not significantly less parsimonious, reflecting strong character conflict. Factors contributing to this conflict include the isolation of hyaenodontid faunas on different continents during much of the Eocene, canalization and simplification of carnivorous dentitions, and a lack of non-dental material for critical hyaenodontid groups. The new phylogeny is consistent with either an African or an Asian origin for the group.

Glyptodonts are a group of extinct xenarthrans with several anatomical features that make them one of the most bizarre groups of mammals. By the late 19th century, some authors began to analyze the brain of Pleistocene glyptodonts using natural endocranial casts. These studies revealed the small size of the brain of the large Pleistocene forms. However, the evolution of the brain in glyptodonts and how it fits in a phylogenetic context has not been analyzed. In order to evaluate the evolution of the brain in this group, we described the first digital endocranial cast of the late Miocene glyptodont Pseudoplohophorus absolutus and compared it with digital endocranial casts of the Pleistocene glyptodonts Glyptodon, Doedicurus, and Panochthus and the extant armadillos Dasypus, Euphractus, Chaetophractus, and Zaedyus. The endocast morphology of P. absolutus is similar to that of Pleistocene glyptodonts: large olfactory bulbs, a small cerebrum with a single neocortical sulcus, and a large cerebellum. However, the relative brain size is larger than in the Pleistocene forms, with values of the encephalization quotient (EQ) close to that of extant armadillos. A comparison between xenarthrans orders shows that Cingulata (glyptodonts and armadillos) have lower EQ values than Pilosa (sloths and vermilinguas). This could possibly be related to certain restrictions and benefits imposed by the presence of the carapace in cingulates. Furthermore, because the carapace restricts the development of the cervical musculature that supports the skull, the small size of the brain in glyptodonts could be a trade-off (along with others) to reduce the weight of the skull.

A new therocephalian therapsid, Ichibengops munyamadziensis, gen. et sp. nov., is described on the basis of two partial skulls from the upper Permian (Wuchiapingian) upper Madumabisa Mudstone Formation of the Luangwa Basin, Zambia. The specimens offer insights into the diversity of therocephalians in a poorly sampled region, preserving unique maxillary structures, dental morphology that is intermediate between basal therocephalians and eutherocephalians, and a maxillovomerine bridge forming an incipient secondary palate. A phylogenetic analysis of 135 craniodental and postcranial characters from 56 therapsid taxa (including 49 therocephalians) recovered I. munyamadziensis as the sister taxon of the Russian Chthonosaurus, with both taxa resolving near the hofmeyriid C whaitsiid C baurioid clade (either as the sister group to this clade or nested near whaitsiids). Ichibengops shares with Chthonosaurus several features, including a ventral maxillary flange in which the upper postcanines are situated (also in Lycosuchus), anteroposteriorly short suborbital vacuities with strongly scalloped anterior borders, a furrowed or ridged surface texture on the palatal surface of the palatine, and a possible maxillovomerine bridge (although this latter structure is incompletely preserved in Chthonosaurus). The new taxon, along with its proposed relationship to Chthonosaurus, adds to a list of sister-group pairs of Wuchiapingian tetrapods in southern Gondwana and Laurasia, indicating that effective, though largely unknown, dispersal routes persisted in Pangea at least through early late Permian times.

Although Cenozoic protoceratid artiodactyls are known from throughout North America, species referred to the Miocene protoceratine Paratoceras are restricted to subtropical areas of the Gulf Coast and southern Mexico and tropical areas of Panama. Newly discovered fossils from the late Arikareean Lirio Norte Local Fauna, Panama Canal basin, include partial dentitions of a protoceratid remarkably similar to those of Paratoceras tedfordi from Mexico, suggesting a rapid early Miocene colonization of recently emerged tropical volcanic terrains (Las Cascadas Formation). Partial lower dentitions from the overlying shallow marine to transitional Culebra Formation (early Centenario Fauna) are here referred to Paratoceras orarius, sp. nov., based on relatively small size, shallow mandible anterior to p3, and narrow cheek teeth. New early Hemingfordian protoceratine fossils from the upper part of the Cucaracha Formation (late Centenario Fauna) include a partial male skull and several dentitions that, together with specimens previously referred to P. wardi (only known from the Barstovian of Texas), are here referred to Paratoceras coatesi, sp. nov., based on distinctly more gracile cranial ornamentation, relatively longer nasals, a smaller and wider lower p4 (relative to m1), and more bulbous lower premolars. Results from a cladistic analysis of 15 craniodental characters coded for 11 protoceratine species suggests that Paratoceras is a monophyletic clade with its origin in subtropical areas of Central America, spreading into the tropics of Panama during the early Miocene (Arikareean through Hemingfordian North American Land Mammal Ages [NALMAs]), and later inhabiting subtropical areas of the Gulf Coast during the middle—late Miocene (Barstovian through Clarendonian NALMAs).

Whereas fossil turtle eggs have a near global distribution and range from Middle Jurassic to Pleistocene, they are rarely documented from the Mesozoic of Gondwana. Here, we report three fossil turtle eggs from the Upper Cretaceous (Campanian) of the Morondava Basin, Madagascar. The spherical eggs range in size from 33.5 to 35.5 mm and have an average eggshell thickness of 440 mm. They can be confidently identified as rigid-shelled turtle eggs by the presence of tightly packed shell units composed of radiating acicular crystals and a shell unit height to width ratio of 2:1. Lack of associated skeletal remains precludes taxonomic identification of the eggs. Although a large vertebrate fauna has been reported from the Upper Cretaceous of Madagascar, these specimens are the first eggs from the Mesozoic of the island.

Six species of soft-shelled turtles (Trionychidae) have been previously described from the Oligocene of Asia. Four of those species were described based on fossils from the Turgai Depression and Zaisan (D Zaysan) Depression of Kazakhstan. We reevaluate those four species in light of new material from the Oligocene Chelkarnurinskaya Svita of the Turgai Depression. The new material is described and identified as Ulutrionyx ninae. Based on our revision, only two valid species of trionychid are present in the Oligocene of Asia. The relatively low diversity of Oligocene trionychids in Asia is mirrored by low trionychid diversity in North America during the same time period.

A partial articulated skeleton of a desmostylian was found in siltstone of the Sooke Formation in the streambed at the mouth of the Sombrio River in Juan De Fuca Provincial Park, Vancouver Island, British Columbia, Canada. Another exposure of the Sooke Formation southeast of the locality has been dated to Chron C6Cr age, 24.1–24.8 Ma. This specimen includes the left side of the skull, two molars, a premolar, canines, partial scapula, nearly complete humerus, and numerous vertebrae and ribs. Molar characteristics are the same as material of Behemotops proteus from the Pysht Formation of Washington State, which is near the type locality of Behemotops proteus of the upper Oligocene Pysht Formation, Washington State. Previous specimens of B. proteus were limited to lower jaws and portions of the upper and lower postcanine dentitions. The slightly smaller Behemotops katsuiei from Japan is known from more elements, yet its cranial material is limited to the posterior portion of the cranium and a small portion of the zygomatic arch. This new material allows us to see that Behemotops cf. B. proteus had cranial features much like those seen in Cornwallius sookensis of North America. These include a postorbital process of the jugal, with the zygomatic process of the squamosal not dorsally expanded, a concave hard palate, enlarged canine tusks that point ventrally, and a narrow, curved incisor arcade on a narrow rostrum. This is different from specimens previously referred to as Behemotops emlongi and then synonymized with B. proteus, which have a broad symphysis with large tusks. These specimens formerly known as B. emlongi are now referred to a new genus.

The Late Triassic—Early Jurassic Elliot Formation of South Africa is one of the most important geological formations worldwide for understanding the early evolution of sauropodomorph dinosaurs. However, many of the taxa currently recognized as valid within its lower strata remain either poorly understood, vaguely diagnosed, or both. The recent discovery of an articulated partial skeleton of a single individual of the enigmatic lower Elliot genus Eucnemesaurus provides an important opportunity to expand our understanding of the anatomy and phylogeny of this poorly known taxon. A comprehensive investigation of the morphological relationships of this new specimen identified key features, pertaining primarily to the femoral shaft and distal tibia, which distinguish it from the only other previously named species of Eucnemesaurus—E. fortis. A new species, E. entaxonis, is erected within which to accommodate it. A cladistic analysis confirms the monophyly of Eucnemesaurus, as well as its continued inclusion within the low-diversity ‘Riojasauridae.’ Nonetheless, this result highlights continued uncertainties regarding the constituency of the Riojasaurus hypodigm. The relatively robust pedal architecture of E. entaxonis suggests an unexpectedly early experiment in a slower, subgraviportal form of locomotion within Late Triassic basal Massopoda, whereas the intriguing mosaic of plesiomorphic and derived characters evident in E. entaxonis raises questions regarding the hypothesized population dynamics of the basal-most sauropodomorph taxa of the lower Elliot Formation. This latter concern has particular bearing on newly observed inconsistencies in the prevailing hypodigms of other lower Elliot basal sauropodomorph taxa such as Melanorosaurus.

Brachiosaurid sauropods achieved a broad distribution during the Late Jurassic, which has been considered to provide evidence of their origins during the Middle Jurassic, prior to the breakup of Pangea. In contrast to their broad geographic distribution during the Late Jurassic, formally named brachiosaurid species from the Cretaceous have so far been restricted to the Aptian—Albian of North America, which has been interpreted as a signal of differential extinction and/or a bias in the Early Cretaceous fossil record. Here we describe a new brachiosaurid titanosauriform taxon from the Early Cretaceous of Colombia, which is represented by axial elements. The material was recovered from marine sediments of the Paja Formation (Barremian), close to the locality of Villa de Leiva. The weakly laterally expanded and divided transverse processes of the anterior-most caudal vertebrae allows the recognition of a new sauropod taxon, Padillasaurus leivaensis, gen. et sp. nov. In order to test the phylogenetic relationships of the new taxon, we performed a cladistic analysis that recovered Padillasaurus as a brachiosaurid titanosauriform. This position is supported by a combination of characters, including the presence of blind fossae in anterior caudal vertebrae. Among titanosauriforms, the presence of blind fossae in anterior caudal vertebrae is an apomorphic character that is exclusive to Giraffatitan, Venenosaurus, Cedarosaurus, and Abydosaurus. Although more complete remains are needed to test more thoroughly the affinities of the new taxon, the available evidence indicates that brachiosaurids survived at lower latitudes in Gondwana until at least the Early Cretaceous.

A new species of an edaphodontid holocephalian, Edaphodon snowhillensis, sp. nov., is described based on a complete dentition collected in the late Campanian Herbert Sound Member of the Snow Hill Island Formation of James Ross Island, Antarctica. The dentition consists of paired vomerine, mandibular, and palatine tooth plates, which are almost completely preserved. The new species is characterized by a unique character combination out of which the presence of a subquadrangular vomerine tooth plate and a horse-hoof-shaped anterior outer tritor in the mandibular tooth plates appear to be unique characters among the edaphodontids. Edaphodon snowhillensis, sp. nov., represents the most complete dentition of a holocephalian fish from the Southern Hemisphere and the earliest record of the genus Edaphodon from the Antarctic continent and the Weddellian Biogeographic Province. Also, E. snowhillensis, sp. nov., is the southernmost specimen of this genus and according to the size of the tooth plates is one of the largest chimaeroid fish known.

Eorhincodon casei from Russia and Megachasma comanchensis from the United States are two Cretaceous taxa initially described as putative planktivorous elasmobranchs, but the type specimens of these two taxa were subsequently reinterpreted to represent taphonomically abraded teeth of an odontaspidid, Johnlongia Siverson (Lamniformes: Odontaspididae). Here, we redescribe the type materials of ‘E. casei’ and ‘M. comanchensis’ and describe additional specimens of these species from other Late Cretaceous localities in Russia and the United States. These specimens demonstrate that (1) the two fossil taxa are valid species; (2) they warrant the establishment of a new genus of presumed planktivorous sharks, Pseudomegachasma, gen. nov., to accommodate the two species; and (3) the new genus is sister to Johnlongia and together constitute a new subfamily Johnlonginae, subfam. nov., tentatively placed in the family Odontaspididae sensu stricto. This taxonomic placement indicates that the putative planktivorous clade was derived from a presumed piscivorous form (Johnlongia), with an implication that Pseudomegachasma, gen. nov., evolved a plankton-eating habit independent of the four known planktivorous elasmobranch clades (Rhincodontidae, Megachasmidae, Cetorhinidae, and Mobulidae). It also indicates that planktivorous diets evolved independently at least three times in the order Lamniformes (i.e., Megachasmidae, Cetorhinidae, and Odontaspididae), and more significantly, Pseudomegachasma, gen. nov., would represent the oldest known plankton-feeding elasmobranch in the fossil record. The present fossil record suggests that Pseudomegachasma, gen. nov., evolved in a relatively shallow-water environment in Russia in the early Cenomanian or earlier and subsequently migrated to the North American Western Interior Seaway by the mid-Cenomanian.

Penguins have a more than 60 million year long evolutionary history. Thus, stem lineage fossil taxa are key to understanding their evolution. Here, we present data on three virtual endocasts from stem penguin skulls collected from the Eocene La Meseta Formation of Seymour Island (Antarctica), along with comparative data from extant penguins and outgroups. These fossils appear to belong to three distinct species, and represent both the oldest (34.2 Ma) and the most basal penguin taxa that have yielded endocast data. Data collected from the fossils provide new support for several important shifts in neuroanatomy and cranial skeletal anatomy along the transition from stem to crown penguins, including (1) caudal expansion of the eminentia sagittalis, (2) an increase in the overlap of the telencephalon onto the cerebellum, (3) reduction of the bulbus olfactorius, and (4) loss of the interaural pathway. The large semicircular canal diameters of the Antarctic fossils as well as the more crownward stem penguin Paraptenodytes antarcticus together suggest that canal size increased in basal penguins relative to outgroup taxa but later decreased near the crown radiation. As in most other wing-propelled diving birds, the endocasts lack evidence of cerebellar folds and possess a relatively large floccular recess. Several aspects of the endocast morphology, including the exposure of the tectum opticum in dorsal view and the rostral displacement of the eminentia sagittalis away from the border of the cerebellum, are seen neither in crown penguins nor in Procellariiformes (the extant sister clade to Sphenisciformes) and so appear to represent unique characters of these stem taxa.

I describe a new fossil species of the extant anuran genus Lepidobatrachus from late Miocene-early Pliocene sediments of central Argentina. This species was erroneously attributed to the living species L. laevis in prior studies. However, reanalysis of the fossil material demonstrated that some anatomical structures, as well as their taxonomic significance, were misinterpreted. The description and comparative analysis presented here demonstrate that this specimen represents a new fossil species of Lepidobatrachus. Although it possesses most of the possible synapomorphies of Lepidobatrachus, some features of the architecture of the skull of the specimen, specifically the relationships of the palatal surface of the maxilla with the surrounding bones, resemble the skull of other ceratophryid genera. Additionally, the new species differs from all ceratophryids in the absence of a supraorbital shelf. The paleoenvironmental significance of this discovery is also discussed.

Theropod teeth are typically not described in detail, yet these abundant vertebrate fossils are not only frequently reported in the literature, but also preserve extensive anatomical information. Often in descriptions, important characters of the crown and ornamentations are omitted, and in many instances, authors do not include a description of theropod dentition at all. The paucity of information makes identification of isolated teeth difficult and taxonomic assignments uncertain. Therefore, we here propose a standardization of the anatomical and morphometric terms for tooth anatomical subunits, as well as a methodology to describe isolated teeth comprehensively. As a corollary, this study exposes the importance of detailed anatomical descriptions with the utilitarian purpose of clarifying taxonomy and identifying isolated theropod teeth.

Late Jurassic dinosaur faunas from the Southern Hemisphere are still poorly known, and it thus remains unclear whether or not the famous Tendaguru fauna (Kimmeridgian—Tithonian, Tanzania) represents a typical Gondwanan dinosaur assemblage of that time. In South America, only the Oxfordian—Kimmeridgian Cañadón Calcáreo Formation of Chubut Province, Argentina, has yielded more than isolated Late Jurassic dinosaur remains so far. Here we report fragmentary remains of a dipolodocid sauropod from this unit, representing the first record of this family from the Late Jurassic of South America. Incorporating the basal macronarian Tehuelchesaurus, an unidentified brachiosaurid, the dicraeosaurid Brachytrachelopan, and the diplodocid described here, the taxonomic composition of the sauropod fauna from the Cañadón Calcáreo Formation is remarkably similar to that of the Tendaguru Formation, but also to roughly contemporaneous faunas in North America and Europe. The diverse non-neosauropodan sauropod fauna known from the early Middle Jurassic (Aalenian—Bajocian) of the same depositional basin within Chubut Province is congruent with the dominance of non-neosauropodan sauropods in continental faunas globally to at least the Bathonian. These assemblages suggest a rapid faunal turnover within sauropod faunas in the late Middle Jurassic-earliest Late Jurassic at least in western Pangea, through which basal eusauropods were replaced by diplodocoid and macronarian neosauropods. Taking paleogeographical reconstructions into account, this faunal replacement might have taken place in a surprisingly short time interval of maximally five million years close to the end of the Middle Jurassic.

We present the description and taxonomic reassignment of a new genus and species, Atacamaia solitaria, gen. et sp. nov., from Lower Jurassic strata of northern Chile, South America. The fish was previously reported as a new genus of Mawsoniidae, based on one unprepared specimen. The fish is characterized by a combination of numerous intriguing characters, such as the presence of a broad parietal bone partially covered laterally by a series of a few large supraorbital bones, a series of sclerotic bones, a lachrymojugal expanded anteriorly and markedly angled, and a metapterygoid with a well-developed ventral process that is ventral to the dorsal margin of the pterygoid plate. Addition of Atacamaia to previously published matrices produces unexpected collapses of certain nodes in the currently accepted phylogenetic hypothesis of Actinistia, creating many polytomies in the consensus tree. Our cladistic analysis suggests that Atacamaia, gen. et sp. nov., Axelia, and Wimania are closely related and together with Piveteauia, Guizhoucoelacanthus, and Whiteia are members of the order Coelacanthiformes. Based on previous analyses and our results, we recognize this grouping as the family Whiteiidae. Members of Whiteiidae are Triassic forms, except Atacamaia solitaria, gen. et sp. nov., from the Early Jurassic. The new fossil actinistian represents the youngest member of the family and the first discovered on the Paleopacific side of Gondwana; all other members are from China, Madagascar, and Spitsbergen. After comparison of previous hypotheses, we review the higher level taxonomy of Actinistia concerning the monophyly of Coelacanthiformes, Latimeroidei, Mawsoniidae, and Latimeriidae and propose a family diagnosis for Whiteiidae.