We describe a new insular endemic lagomorph from the Late Neogene karstic deposits of Minorca (Balearic islands, Spain). Nuralagus rex, gen. et sp. nov., is characterized by an array of odd traits unknown for lagomorphs. Most outstanding are the gigantic size (average 12 kg), the robust postcranial skeleton with unique morphological traits (short manus and pes with splayed phalanges, short and stiff vertebral column with reduced extension/flexion capabilities), and the relatively small size of sense-related areas of the skull (tympanic bullae, orbits, braincase, and choanae). These morphological traits denote an important decrease in locomotor and neurological activities and, hence, a decrease in metabolic energy expenditure, which is concordant with the ecological conditions of the insular environment characterized by absence of predators and low levels of resource supply. Our discovery enhances the importance of the frequently neglected fossil record for our understanding evolution on islands, because it provides the perspective of time and adds valuable data from fossil insular ecosystems unaffected by anthropogenic alterations.

A new Early Carboniferous (Mississippian, mid-Viséan) chondrichthyan, Reginaselache morrisi, n. g., n. sp., from non- or marginal marine sandy mudstones of the Tetrapod Unit of the mid-Viséan (330 Ma = top Holkerian/basal Asbian) Ducabrook Formation, northwest of Springsure, central Queensland, is referred to the order Xenacanthiformes. The taxon is represented by robust diplodont teeth with multicristate cusps, a prominent rounded coronal button, and a horseshoe-shaped labial boss. Rare spine fragments from the type locality, and a partial lower jaw from a site close by are also tentatively referred to the taxon. Reginaselache morrisi was a medium-sized, ca. 1 m long shark with numerous teeth, probably feeding on smaller paleoniscoid and other fishes and/or invertebrates. Analysis of the teeth and comparison with those of other Carboniferous and later Paleozoic xenacanthiforms shows that the tooth cusp morphology is closest to those of Triodus Hampe and Bohemiacanthus Schneider. A restricted cladistic analysis of the xenacanthiforms with outgroups Leonodus Mader, Phoebodus St John and Worthen, and Antarctilamna Young supports the family Diplodoselachidae Hampe as a clade comprising just two genera, Diplodoselache and Reginaselache.

The Siluriformes constitutes an important monophyletic ostariophysan group of mainly freshwater fishes that occurs in almost all continents. They are extremely abundant and diverse in South America, where the oldest otophysans and siluriforms occur. We restudied two putative catfish species from the early Eocene lacustrine Tufolitas Laguna del Hunco of northwestern Patagonia, Argentina, concluding that Arius argentinus Dolgopol, 1941, is a junior synonym of Bachmannia chubutensis Dolgopol, 1941. Phylogenetic analyses were performed to show the relationships of B. chubutensis, which appears as the sister group of Diplomystes. Bachmannia chubutensis is one of the most primitive catfishes known and we based on it a new family. The family is clearly diagnosed by the presence of a anterior ventrolateral expansion of cleithrum, short maxilla with two rows of teeth, double-headed autopalatine, accessory tooth plates, very huge teeth, supraoccipital process long and acute, first and fifth vertebrae not joined to complex vertebra, neural arch of fifth and sixth vertebrae very well developed, enlarged supraneural 5, suture between ceratohyal and epihyal without interdigitations, suture between contralateral cleithra and coracoids without interdigitations, six hypurals. Individuals of B. chubutensis inhabited lakes and were preserved into fine-grained, laminated fall-out and reworked pyroclastic debris inside a caldera.

A partial reptile skull collected from the Lower Triassic (Induan) Barendskraal locality of South Africa is referable to the procolophonid parareptile Sauropareion anoplus. The specimen comprises the left side of the skull roof, palate, and mandible, and preserves areas not preserved or accessible in the skulls of previously published specimens, including fragmentary remains of the premaxilla, the anterior end of the maxilla, and the anterior end and lingual aspect of the mandible. The maxilla exhibits a maxillary depression that is similar in both shape and relative size to that seen in Procolophon trigoniceps, an anterolateral maxillary foramen that is indistinguishable from those seen in other procolophonoids, and 11 conical teeth. The suborbital foramen is formed ventrally by the palatine and the ectopterygoid. The dentary and the coronoid are fused together indistinguishably in lateral aspect. The marginal teeth appear to be anchored to the jaws by bone of attachment. The dentary teeth are exposed in lingual aspect and appear to be ankylosed to the summit of the bone, suggesting acrodont tooth implantation. Tooth replacement is seen in these teeth, where the lingual surface of a single tooth crown base in the middle of the dentary series is excavated for the apex of a replacement tooth crown, but the excavation does not extend ventrally onto the lingual surface of the bone. Considering that no extant reptiles with acrodont tooth implantation exhibit tooth replacement or bone of attachment, we tentatively regard protothecodonty to be present in S. anoplus.

New remains of an anuran and various squamate reptiles have been recovered from Cenomanian paralic deposits of Charentes (southwestern France). Remains are not abundant, yet they make up one of the most diverse Cenomanian assemblages and the most diverse one from Europe. Nine or 10 taxa are present. Precise taxonomic assignment of most of them is not always possible, even at family level; however, the mosasauroid Carentonosaurus mineaui, the snake Simoliophis rochebrunei, as well as a possible dolichosaurid lizard are identified. At least two taxa are new, but they cannot be named on the basis of the available material. Among the fossils are an anuran and terrestrial lizards that rank among the very scarce ones from the Cenomanian. In addition, three distinct snakes are among the oldest ones. The faunas from the Cenomanian of Charentes are mixtures of terrestrial and predominantly marine taxa.

A new genus and species of Pachypleurosauria, Dianopachysaurus dingi, gen. et sp. nov., from a recently discovered Middle Triassic Lagerstätte in the Anisian Guanling Formation of Yunnan Province is described. The monophyly of Pachypleurosauria, including all potential Chinese pachypleurosaurs in this study, is supported by the rigorous cladistic analysis conducted here. Phylogenetic relationships of Chinese pachypleurosaurs are clarified. Wumengosaurus occupies the most basal position within Pachypleurosauria. Keichousaurus and Dianopachysaurus form the monophyletic Keichousauridae that is the sister group of all European pachypleurosaurs. Our cladistic analysis also supports a previously proposed paleobiogeographic hypothesis of an eastern Tethyan origin of pachypleurosaurs and their migration into the western Tethyan faunal province. The existence of a long ghost lineage as required by the paleobiogeographic hypothesis is greatly shortened by the discovery of Dianopachysaurus.

A new genus and species of marine reptile is described from the Pelsonian (Anisian, Middle Triassic) of Luoping County, Yunnan Province, southwestern China. This diapsid reptile with a secondarily closed upper temporal fossa is the sister taxon to Saurosphargis from the lower Muschelkalk (Anisian, Middle Triassic) of central Europe. It further emphasizes the close faunal affinities between the Eastern and Western Tethyan realm. The new taxon is convergent on cyamodontoid placodonts in having developed a dorsal body armor composed of small osteoderms. The underlying ribs are transversely broadened so as to establish contact along their length, thus forming a closed dorsal ‘rib basket,’ a unique morphology shared with Saurosphargis.

The braincase of a polycotylid plesiosaur referable to Dolichorhynchops from the Niobrara Formation (Santonian to the earliest Campanian) in Manitoba, Canada, is described. The well-preserved material without matrix permits observation of various anatomical features of the polycotylid braincase with unprecedented clarity. A virtual reconstruction of the braincase was created by using a three-dimensional scanning technique that produces accurate reconstruction of missing or damaged elements and demonstrates the three-dimensional relationships among the elements. Comparison with other plesiosaurian braincases revealed previously unrecognized characters and character states. The I-beam-shaped parasphenoid, the relatively short pituitary fossa, and the anterior process of the prootic are possible synapomorphies of the Polycotylidae or of its subclades. It could be a challenge to confirm the presence of the supraoccipital process and its median ridge, as well as the presence of the fenestra ovalis, in polycotylid skulls because of the location and orientation of these structures. Variable morphology of basioccipital-basisphenoid contact and the paroccipital process in Dolichorhynchops and related taxa require further investigation. The I-beam of the parasphenoid and the wide contact surfaces of the basioccipital and neighboring elements provide more resistance to flexion of the braincase. Distribution of the extensive pterygoid-basicranium contact, the shape of foramen magnum, anterior process of the prootic, and the short pituitary fossa do not confirm the current phylogenetic hypotheses. The location and orientation of the fenestra ovalis suggest the lack of a tympanic ear in this plesiosaur.

Current knowledge of plesiosaurs of clade Cryptoclidia is constrained by a lack of fossils from outside the Oxford Clay deposits of England. Recent fleldwork in the Sundance Formation of the Bighorn Basin, Wyoming, has resulted in the recovery of significant new fossils of cryptoclidid plesiosaurs, including the small-bodied form Tatenectes laramiensis. A new partial skeleton of this taxon is reported here; it is the most complete and best-preserved example of the taxon found to date, comprising a complete dorsal vertebral series, many ribs and gastralia, and a complete pelvic girdle. This skeleton illuminates several unique features of the taxon, including a novel pattern of midline pachyostosis in the gastralia. In addition, a range of both axial and appendicular morphological features reveals that Tatenectes had a body shape unique among known plesiosaurs, characterized by extreme dorsoventral compression, and modest anteroposterior reduction. The combination of the new skeleton with information from previous finds allows the first reconstruction of the taxon. Tatenectes had a dorsoventrally compressed, oblate spheroid body shape, with a high skeletal mass concentration in the ventral elements. We hypothesize that these features were adaptations for increased near-surface stability, perhaps allowing access to above normal wave base, inshore environments in the shallow Sundance Seaway.

The holotype and only known specimen of the pliosauroid plesiosaur Hauffiosaurus zanoni O'Keefe is a substantially complete and almost entirely articulated skeleton from the Toarcian Posidonien-Schiefer (Upper Lias, Lower Jurassic) of Holzmaden (Baden-Württemberg), Germany. The original description of this specimen was preliminary, and this paper presents a detailed re-description and revised diagnosis of the specimen, thus adding significant, new anatomical information. Characters such as the presence of a lateral palatal fenestra and the absence of a contact between the internal nares and the palatines are examples of phylogenetically relevant characters. The specimen presents a novel and unique combination of characters and body proportions, including a long ilium, short ischia, and propodials longer than any of their associated girdle bones, that separate it from all other pliosauroid taxa. Its elongate snout and long, slender teeth imply that this species most likely had a prey preference of fish.

The periorbital morphology of goniopholidids is discussed, exploring the diversity of patterns and the relevance of the data for phylogenetic studies. Revision of material is focused on Goniopholis spp. and aff. Goniopholis spp., from England, Germany, and Belgium, providing a comparative description of their interorbital morphology. Traditional interpretation of the interorbital elements in species of Goniopholis (G. simus, G. baryglyphaeus), where the frontal is interpreted as excluded from the orbit by a prefrontal-postorbital contact in the skull roof, is contested and clarified through the analysis of new specimens, including a morphometric analysis. In Goniopholis, failure to identify the palpebral and its subtle contact with the prefrontal has lead to misinterpretation of elements and structures near the orbit, and the differential preservation/loss of palpebrals explains variability of the orbit in shape and orientation. In all European goniophilidids the frontal reaches the primary orbital border and there is no prefrontal-postorbital contact on the dorsal surface of the skull. Extensive contact of the palpebral with the primary orbital border creates a secondary (functional) orbital border, from which the frontal is excluded in most taxa. The condition is not exclusive of European goniopholidids and is paralleled by protosuchids, peirosaurids, and baurusuchids. At least four main morphological patterns are recognized, revealing a high diversity of European goniopholidids.

A three-dimensionally preserved metriorhynchid braincase from the Oxfordian of northern Chile is described. The specimen is referred to the metriorhynchid Metriorhynchus cf. M. westermanni. The excellent preservation provides clear sutures and a detailed description, and X-ray computed tomographic (CT) scanning provides internal anatomical details. The general pattern of the orbitotemporal region is consistent with that of the basal thalattosuchian Pelagosaurus typus as described recently. The specimen from northern Chile shares with other metriorhynchids (e.g., Cricosaurus araucanensis, Metriorhynchus westermanni, M. casamiquelai, and Dakosaurus andiniensis) a dorsally exposed laterosphenoid, a laterosphenoid-prootic suture forming a blunt crest separating the supratemporal fenestra into two fossae for muscular attachment, and the quadrate incompletely sutured to the braincase. Thus, these features characterize not only basal but derived Thalattosuchia, as suggested by previous authors. The main difference in the orbitotemporal region is that in the specimen described herein, and in the other metriorhynchids examined, the trigeminal fossa is developed mainly caudal to the trigeminal foramen, whereas in P. typus the fossa is developed rostral and caudal to the trigeminal foramen. CT scanning indicates the presence of enlarged dorsal dural venous sinuses overlying the brain, as it has been described recently in Steneosaurus pictaviensis, and a well-developed sinus within the quadrate. The large foramen ventrolateral to the occipital condyle, which characterizes metriorhynchids, is confirmed as the entry for the internal carotid artery.

Carnotaurus sastrei is a large abelisaurid dinosaur from the Upper Cretaceous of Patagonia. Its remains include an almost complete skeleton with a well-preserved skull and braincase. Because relatively few abelisaurid braincases are known, the description of the Carnotaurus braincase is important for understanding the variability of this complex structure within the clade. Carnotaurus exhibits traits that characterize the abelisaurid basicranium, such as a well-developed preotic pendant, solid basipterygoid processes, and pneumatic basisphenoid, subsellar, and lateral tympanic recesses. The basipterygoid processes do not project laterally, unlike the divergent processes observed in other abelisaurids. Carnotaurus shares with the Malagasy abelisaurid Majungasaurus crenatissimus caudodorsally oriented paroccipital processes and a maxillomandibular foramen for the trigeminal nerve that in lateral view is aligned with the nuchal crest. The detailed description of the braincase of Carnotaurus presented here provides a better cranial anatomical record of this Patagonian abelisaurid and preliminary insights to the neurocranial morphology within the group.

Many disarticulated bones from multiple individuals of a primitive therizinosaurian, referred to Falcarius utahensis, were found in the paucispecific Crystal Geyser bonebed in the Lower Cretaceous Cedar Mountain Formation of eastern Utah. To date, more than 2000 specimens from this species have been excavated. Included in this collection are two partial braincases, one of which is designated the holotype. Here we describe the braincase morphology of Falcarius utahensis. These specimens help establish the primitive cranial condition for the Therizinosauria and further substantiate intraspecific and contralateral braincase pneumatic variation in theropods. When combined with new observations on the cranial remains of the therizinosaurid Nothronychus mckinleyi derived from computed tomographic (CT) scans, the braincase morphology of Falcarius clarifies several evolutionary trends within the Therizinosauria and establishes a suite of synapomorphies for the Therizinosauridae. Trends within the clade include increased basicranial pneumatization (the development of a basisphenoid bulla and loss of external subcondylar recesses), anterior deflection of the supraoccipital, and the reduction of points of origin of the craniocervical musculature, associated with the loss of discrete basipterygoid processes, probably due to incorporation of these structures into the expanded hyperpneumatic bone. Finally, CT scans reveal a complete, nearly avian, inner ear with bird-like semicircular canals and a long cochlea indicating broad frequency discrimination.

The anatomy of a new subadult specimen of eutherocephalian therapsid, attributed to Promoschorhynchus cf. P. platyrhinus, is described from lowermost Triassic Lystrosaurus Assemblage Zone strata in the main Karoo Basin of South Africa. The specimen preserves information previously unknown in the genus, including details of the posterior region of the skull and intertemporal region, and a partial (though disarticulated) postcranial skeleton. A cladistic analysis of 32 therapsid taxa, including 24 Permo-Triassic therocephalian genera, and 121 craniodental and postcranial characters supports the specimen's placement within the Permian akidnognathid genus Promoschorhynchus (making it the youngest documented occurrence of this taxon) within a monophyletic Therocephalia. Inclusion of new postcranial characters strengthens support of the therocephalian clade. The new record of Promoschorhynchus offers insights into the diversity of eutheriodonts across the Permo-Triassic boundary (PTB) in the Karoo Basin. In contrast to cynodonts, therocephalians exhibited decreased rates of cladogenesis across the PTB, with several Triassic lineages having roots in the Late Permian rather than representing earliest Triassic radiations.

The Taeniodonta is a group of eutherian mammals from the Paleogene of North America, which evolved rapidly in the Paleocene to achieve, in some forms, large body size, hypselodont (i.e., evergrowing) canine and postcanine teeth, and peculiar patterns of tooth wear. Eleven genera of taeniodonts occur in two subgroups, recognized at the level of families or subfamilies depending on author, the Conoryctidae and the Stylinodontidae. There has not been a comprehensive computer-assisted phylogenetic analysis of the taeniodonts, and questions have arisen over the monophyly of the taeniodonts and the conoryctids. Cladistic analyses based on thirty-seven dental characters using NONA and Winclada showed that two subclades of Taeniodonta are well supported, a clade consisting of the conoryctids exclusive of Onychodectes (i.e., Conoryctella, Conoryctes, and Huerfanodon) and a clade consisting of all the known stylinodontids (Wortmania, Schochia, Psittacotherium, Ectoganus, and Stylinodon). Stratocladistic analysis, which takes into account the temporal sequence of taxa in the fossil record, supports the results of the morphological analysis. The Late Cretaceous taeniodont Schowalteria occupies the most basal position in taeniodont phylogeny, pre-dating an inferred conoryctid-stylinodontid split in the early Paleocene, and establishing the taeniodonts as monophyletic.

Extant large members of the order Carnivora show high variability in feeding adaptation. Morphology of their teeth and skull is a primer to predict diet in both extant and extinct species. Here I present a complete geometric morphometric survey of mandible of large (>7 kg) Carnivora in order to make paleoecological predictions for selected Plio-Pleistocene taxa. Mandibular size and shape data support a strong differentiation between families but also convergence due to functional adaptations to hunting prey. Linear discriminant function analyses are performed in order to obtain dietary predictions on fossil taxa with statistical accuracy. There is a high level of discrimination among dietary categories, especially when subsets of predator and non-predator carnivores are analyzed separately. New insights emerge for Plio-Pleistocene fossil taxa whose paleoecology was previously inferred. Mandibular size and shape data are accurate dietary predictors in large carnivores, with size being more relevant to clarify adaptations in killing prey of different size classes.

We describe here a new species of gigantic otter, Enhydriodon dikikae, sp. nov., from the Pliocene of Dikika, in the lower Awash valley of Ethiopia. The holotype consists of an associated snout and mandible, and is the most complete fossil specimen of a large bunodont otter. In some features, such as its very large size, the loss of anterior premolars, the tall protocone of P4, and the divided paraconid of m1, this species illustrates the culmination of general trends in this group, but the most remarkable part of its dentition is the broad incisor arch and powerful canine battery. The purported distinction between Enhydriodon and Sivaonyx is discussed, and the hypothesis of distinct African and Asian lineages is rejected. Postcranial remains confirm that Enhydriodon dikikae, sp. nov., was probably mostly terrestrial, but its diet remains uncertain, as none of the suggested preys fully explains the anatomical adaptations and relative abundance of this species.

New fossils representing two species of the fur seal Callorhinus are reported from the uppermost Pliocene to lower Pleistocene Rio Dell Formation of northern California. The finds include latest Pliocene-earliest Pleistocene dentarles and postcrania of Callorhinus gilmorei, and a partial dentary of early Pleistocene age identified as Callorhinus sp. The aforementioned material is ascribed to C. gilmorei due to the incipient single-rooted condition of the p1–2, retention of double-rooted p3–m1, and overall small size. The dentary identified as Callorhinus sp. exhibits a more derived pattern of tooth morphology, including single-rooted p1–p4 (and double-rooted ml), larger size than C. gilmorei, and in the size range of extant Callorhinus ursinus (which typically exhibit fused roots on all postcanine teeth). Fusion of postcanine roots began with the p2 and continued posteriorly, and is likely an adaptation to accommodate crowded teeth anteriorly in the jaws. Callorhinus gilmorei has previously been reported from the upper Pliocene of southern California and Japan, and this new record extends the range of this taxon further north in the Northeast Pacific. Callorhinus sp. is the most complete pinniped fossil to be described from the early Pleistocene of the Northeast Pacific. The wide biogeographic range of Callorhinus during the Pliocene and Pleistocene documents the persistence of this taxon, potentially as a Pliocene-Holocene anagenetic lineage. This highlights the antiquity of the Callorhinus lineage, which has persisted in the Northeast Pacific since the Pliocene, establishing it as the oldest and earliest diverging crown otariid.

The Machairodontinae fossil record in South America is not very diverse. Until now, only the genus Smilodon (Smilodontini) has been reported, with likely a single species, S. populator. A second taxon of Machairodontinae was referred to Homotheriini and to the genus Xenosmilus, but the age to which it was assigned, early to middle Pleistocene, is uncertain, because it was recovered out of stratigraphic context. At present, the Venezuelan saber-toothed cat record is limited to the late Pleistocene, and consists of fossils found in Mene de Inciarte (state of Zulia), and from Zumbador cave deposit in the state of Falcón. Here we report a new species of Machairodontinae Homotherium venezuelensis, nov. sp., as well as the first record of Smilodon gracilis in South America. Both were found in El Breal de Orocual, a tar seep in the state of Monagas, northeastern Venezuela. The age of the deposit has been interpreted as early to middle Pleistocene by thermoluminescence dating. We have been able to identify 30 vertebrate taxa, suggesting a paleoenvironment similar to the Venezuelan llanos today: an extensive savanna with rivers and patches of gallery forest. The saber-toothed cats described here demonstrate that the biogeography of Neotropical felids is more complex than previously thought, and allow us to identify new invasions and delimit the times during which they occurred. The fossils from Orocual represent the first record of Homotherium for South America, indicating that scimitar-toothed cats invaded this continent as early as the early—middle Pleistocene.

The Tapiridae of the Swiss Molasse Basin from the late Oligocene to the early Miocene are reviewed. Fossil remains that have not previously been described are identified, old descriptions and identifications from previous works are reassessed, and specimens from Switzerland and France are compared, specifically Protapirus bavaricus from Ebnat-Kappel (MP28) and Rüfi bei Schünis (MP29), Protapirus aginensis from La Milloque (France, MP29), Protapirus douvillei from Buchberg 6 (MN4), Paratapirus helvetius from Haslen (Switzerland, MP28-30), Paratapirus intermedius from Saulcet (France, MN1), Höhronen (MN1), and Brüttelen 1 (MN3a), and Eotapirus broennimanni from Wischberg (MN1) and Benken (MN3-4?). These new data enable emended specific diagnoses for Protapirus bavaricus, P. aginensis, and P. douvillei. A late Oligocene (MP28-30) age for the locality of Haslen—the neotype locality of Paratapirus helvetius—is also attributed, based upon the literature and personal observations. Furthermore, a new and precise biostratigraphic range of the European Tapiridae at the species level is proposed for the Oligocene and early Miocene of Western Europe. The paleoecology of tapirs and their diversity and evolution through the Oligocene—Miocene transition are discussed and compared with contemporaneous large mammals such as Rhinocerotoidea, Anthracotheriidae, and Suoidea.