For over a century, the baenid turtle Boremys has been recognized as being restricted to the Campanian of North America. Herein we describe new material of Boremys sp. from the Hell Creek Formation (Maastrichtian) and Fort Union Formation (Puercan) of southwestern North Dakota and eastern Montana, increasing the stratigraphic range of this taxon by 11 million years. The material was recovered from the base of the Hell Creek Formation to 14 m above the pollencalibrated K/T boundary in the basal Fort Union Formation. Most of the specimens consist of isolated shell elements, which are easily misidentifled as belonging to a kinosternid or chelydrid turtle, but complete shells are present as well. The presence of Boremys sp. in the Hell Creek formation increases the baenid taxonomic diversity of this particular rock unit to nine and the overall turtle diversity to 20 taxa, and the presence of Boremys sp. in the Fort Union Formation increases the number of baenid lineages that survive the K/T extinction event to eight.

A new locality near the Permo-Triassic boundary in Tasmania, Australia, has yielded a number of specimens of the brachyopid stereospondyl, Bothriceps australis, whose provenance was unknown previously. An articulated diplospondylous vertebral column of a morphology typical only of the Tupilakosauridae was found at the same locality. Although the Brachyopidae and Tupilakosauridae have skulls of similar shape, most authors have regarded them as not closely related. Phylogenetic analysis confirms that the Brachyopidae and Tupilakosauridae are both members of the Stereospondyli but are not closely related, despite the remarkable similarity of the Bothriceps and tupilakosaur vertebral columns.

A new plioplatecarpine taxon, Latoplatecarpus, gen. nov., is proposed here to incorporate two species, L. willistoni, sp. nov., and L. nichollsae (comb. nov.). The new genus is currently restricted in distribution to the lower middle Campanian of North America. Phylogenetic analysis incorporating 97 morphological characters and 17 ingroup taxa indicates that (1) Ectenosaurus clidastoides is the basal-most member within the Plioplatecarpinae; (2) Platecarpus planifrons is generically distinct from P. tympaniticus; (3) Latoplatecarpus willistoni, gen. et sp. nov., constitutes the basal-most member within the clade that is sister to Platecarpus tympaniticus; and (4) as many as 17 unequivocal character changes support the clade comprising the three post-middle Campanian Plioplatecarpus species. Plesioplatecarpus, gen. nov., is erected to establish Plesioplatecarpus planifrons (comb. nov.). Further, we propose that the North American specimens referred to Platecarpus somenensis pertain to Latoplatecarpus nichollsae, based on the available phylogenetic, ontogenetic, biostratigraphic, and paleobiogeographic data and interpretations. Consequently, the current study recognizes 11 species within seven genera to constitute the Plioplatecarpinae. Of anatomical note, we suggest that quadrates in most plioplatecarpine taxa including Latoplatecarpus were tilted anteriorly in life, as a result of the suspensorial articulation forming along the distomedial portion of the long suprastapedial process that typifies quadrates in plioplatecarpine mosasaurs.

The vertebrate assemblage of the lower Fremouw Formation has been studied for nearly 50 years, but many components remain poorly known. We describe a partial presacral vertebra and the distal end of a left humerus collected just above the Permian—Triassic boundary in the Shackleton Glacier region of the central Transantarctic Mountains. Our identification of these specimens as archosauromorphs that represent at least one taxon of large-bodied archosauriform increases the known reptile diversity of the Fremouw Formation considerably, and provides the first definitive evidence for the presence of Archosauriformes in the Early Triassic of Antarctica. These records increase faunal similarities between the lower Fremouw Formation and other Early Triassic assemblages. Although the lower Fremouw assemblage is typically considered a subset of the coeval Lystrosaurus Assemblage Zone (LAZ) of South Africa, the discrepancy in inferred body size between the Antarctic specimens and Proterosuchus fergusi, coupled with the fact that the LAZ of the Karoo Basin has been sampled much more thoroughly, suggests a real disparity in the maximum body size of apex carnivores between the lower Fremouw assemblage and the LAZ. The lower Fremouw specimens also demonstrate that one or more lineages of archosauriform had attained the large body size characteristic of later members of the clade very soon after the end-Permian mass extinction. This offers a point of contrast with the global pattern of post-extinction terrestrial communities, which are typified by a marked reduction in body size (the ‘Lilliput effect’).

A new hadrosaurid dinosaur, Acristavus gagslarsoni, is here named on the basis of several autapomorphic characteristics of the frontal, postorbital, and dentary. Acristavus is a member of the newly erected clade Brachylophosaurini, which along with its other members, Brachylophosaurus and Maiasaura, constitutes the earliest hadrosaurine hadrosaurid clade. The new taxon occurred approximately 79 million years ago and has been recovered from the Two Medicine Formation of western Montana and nearly simultaneously in the Wahweap Formation of southern Utah. Corresponding with its age and relationship to the other members of the Brachylophosaurini, it is not surprising that Acristavus possesses traits seen in both Brachylophosaurus and Maiasaura, but not necessarily shared between them. One of the most interesting morphological features of Acristavus is the lack of cranial osteological ornamentation, which is in stark contrast to every other hadrosaurid dinosaur except Edmontosaurus. Combining stratigraphic and phylogenetic data from Acristavus yields support for the hypothesis that the hadrosaurid ancestor did not possess cranial ornamentation, and that the subfamilies Hadrosaurinae and Lambeosaurinae each independently developed display structures.

Three species of gull-like birds were described by Milne-Edwards in the 19th century from the early Miocene of Saint-Gérand-le-Puy, France, two of which have been since then moved to the genus Laricola. These fossils are redescribed and revised in the present study. We further describe two new species of the taxon Laricola, L. intermedia, sp. nov., and L. robusta, sp. nov., as well as two species of a new taxon Sternalara, S. minuta and S. milneedwardsi, thus substantially increasing the number of charadriiform taxa known from this locality. To find out how Laricola relates to modern taxa, we performed a phylogenetic analysis of 41 osteological characters, which resulted in Laricola being placed outside of Lariidae, as early representatives of the newly designated group Laromorphae, which encompasses terns, gulls, and skimmers. The results of our analysis have additionally enabled us to evaluate relationships between extant taxa of the Laromorphae.

Argentoconodon fariasorum is the only triconodont from the Jurassic of South America. Originally described on the basis of an upper molariform, A. fariasorum is now known by several specimens, including one that preserves most of its dentition, upper and lower jaws, and several postcranial elements. Close anatomical similarity exists between Argentoconodon fariasorum, Ichthyoconodon jaworowskorum, from the Cretaceous of Morocco, and the likely Jurassic Volaticotherium antiquus, from China. The results of a phylogenetic analysis including most taxa relevant to addressing triconodont phylogenetic relationships show Argentoconodon and Volaticotherium as a clade, which in turn is more closely related to Ichthyoconodon than to any other taxon. Our most parsimonious hypotheses support a triconodontid ancestry for Argentoconodon, Ichthyoconodon, and Volaticotherium as members of the monophyletic traditional subfamily Alticonodontinae. The inclusion of Argentoconodon among alticonodontines extends the geographical and temporal distribution of this triconodont subfamily to the South American Early Jurassic, resulting in extensive ghost lineages for many triconodontid groups. Postcranial similarities between Argentoconodon and Volaticotherium make it possible that the Argentinean taxon might have had gliding capabilities; if this is the case, our cladistic analysis highlights the possible existence of a gliding clade of triconodonts of wide distribution from at least as early as the Early Jurassic.

Toumaï (Sahelanthropus tchadensis) is, to date, the oldest known hominine. Approximately 7 million years ago, it lived close to the northern shoreline of the paleo Lake Chad, which extended at that time 500 km north of its present location. Here, we describe a new xerine squirrel, Sabara oralacus, gen. et sp. nov., discovered near the site where Toumaï was unearthed. Study of associated fauna is essential to evaluate correctly the precise paleoenvironmental affinities of the first African hominines. The new squirrel displays a mosaic of dental and skull characters characterizing either the tribe Xerini or Protoxerini, which makes its taxonomic assignment at the tribe level difficult. From craniodental characters, we hypothesize that S. oralacus was a ground-dweller, digging burrows, probably with an ecological preference for forest to savannah environments associated with hard fruit-bearing trees.

In this paper, the rodents from the composite section of Torrent de Vallparadís (Terrassa, northeastern Spain) are described, with particular emphasis on the arvicolines. Due to their wide geographical distributions and rapid evolutionary rates, arvicolines are especially useful for biostratigraphical purposes. Eight stratigraphic layers have yielded rodent remains, including representatives of the genera Mimomys, Allophaiomys, Stenocranius, Iberomys, Microtus, Arvicola, Apodemus, Eliomys, and Hystrix. The presence of different rodent species, together with the available magnetostratigraphic data, allows a precise determination of the age of each layer and a detailed correlation with other Spanish Pleistocene sites, particularly those of the Sierra de Atapuerca. The complete studied sequence ranges from the pre-Jaramillo Biharian (1.4–1.2 Ma) to the early Toringian (less than 0.6 Ma.), constituting one of the most complete sequences of the Spanish Pleistocene and covering a time span of especial relevance in relation to the earliest human dispersal into western Europe.

The Meade Basin record of pocket gophers extends from the latest Miocene (Buis Ranch local fauna) to modern time. A primitive species with hypsodont but rooted cheek teeth, Pliogeomys buisi, characterizes the late Hemphillian. Another species of Pliogeomys, P. louderbachi, is described here as a new species from the early Blancan. It is intermediate in dental and mandibular morphology between Pliogeomys and Geomys. The Geomys minor (= G. smithi) lineage displays a stepped dwarfing trend prior to its extinction, whereas the G. jacobi lineage demonstrates an overall pattern of stasis in size. G. jacobi is replaced by G. quinni at the end of the Pliocene, within which there is a significant directional size increase. A late Pliocene immigrant, the new species G. floralindae, appears in the Sanders assemblage. It is briefly replaced by an indeterminate small species in the Nash 72 local fauna. G. tobinensis is found in the Cudahy local fauna. Morphologically modern G. bursarius appears in the Meade Basin during the early Rancholabrean. A small, primitive species, Geomys adamsi, appears only during the early Pliocene at Fox Canyon, and transient Thomomys appear at various times during the Pleistocene, both apparently during cold intervals. A phylogenetic analysis suggests two clades, one uniting Pliogeomys russelli and Geomys adamsi and another including the remaining Meade Basin geomyines. Enhanced species turnover and the last push for modern mandibular morphology is most pronounced in sediments younger than about 2.6 million years ago, corresponding to the first global cooling heralding the Pleistocene.

The taxonomic status of European Plio-Pleistocene badgers is currently uncertain, due to the relative scarcity of their fossil remains. Here we describe craniodental remains from the Iberian locality of Vallparadís, indicating that the extant European badger (Meles meles) was distributed throughout Europe during the late Villafranchian. On the basis of morphological and morphometrical comparisons, we attribute the studied specimens, together with other late Villafranchian and Epivillafranchian badgers from Europe, to M. meles atavus, thereby considering that M. hollitzeri and M. dimitrius (in part) are subjective junior synonyms of the former. Only the early to middle Villafranchian M. thorali can be considered a distinct species, with M. iberica and M. dimitrius (in part) being subjective junior synonyms of this other species. It is concluded that extant European badger species must have diverged from Asian badgers before the top of the Olduvai subchron. Available molecular and paleontological data are consistent with an Asian origin of the Meles lineage, and with M. thorali being the ancestral species that dispersed into Europe attaining a wholly Palearctic distribution by the early Villafranchian. Later, before the top of the Olduvai subchron, M. thorali might have given rise to both the European and Asian badger lineages through a vicariance process prompted by paleoclimatic changes.

An unusual specimen of a perissodactyl from the Bridgerian (late early to early middle Eocene) of Wyoming provides the basis for a new genus and species, Mesolambdolophus setoni. The specimen (MCZ 19585) displays an unusual combination of features: first lower premolar absent; p2 and p3 not molariform; p4 submolariform; anterior end of metalophid lingually placed, contacting metaconid; metaconid not twinned; and large hypoconulid on m3. The orientation of the metalophid excludes this specimen from Ceratomorpha, and the size and characters of this specimen exclude it from any known genus of Bridgerian perissodactyl, as well as from any other Eocene perissodactyl taxon. Including this taxon in a phylogenetic analysis of basal perissodactyls places Mesolambdolophus as sister taxon to Tapiromorpha, but we consider any assessment of the position of Mesolambdolophus tentative at best, given the limitations of analyses of basal perissodactyls currently available. The presence of a small Bridgerian ‘hippomorph’ form that is larger than Orohippus reduces the reliability of assigning isolated postcrania to Bridgerian perissodactyl taxa on the basis of size.