Chimaeroid (Chondrichthyes: Holocephali) mandibular toothplates of Edaphodon kawai, sp. nov., are described from the Cretaceous-Paleogene Takatika Grit of Chatham Islands, New Zealand. This is the first description of a chimaeroid from the Chatham Islands-New Zealand region, extending the geographical and temporal range of this genus globally. The new species is defined by a straight toothplate and long robust beak, which is armed with a long laminated symphyseal tritor and has an elongate anterior outer tritor and a pronounced asymmetric ridge positioned mesially on the oral surface. This unique arrangement may reflect a feeding strategy of cutting and crushing, which differs from most previously identified callorhynchids that possess crushing surfaces only.

The evolutionary origin of the great white shark (Carcharodon carcharias) is unclear, with debate centering around two principal hypotheses. The first, based on similarity in tooth shape, claims that C. carcharias originated from a group of extinct mako sharks that includes Isurus hastalis. The second hypothesis, based mostly on cladistic evidence, claims that C. carcharias originated from the same lineage as the giant megatoothed sharks, sharing a close evolutionary ancestor with the extinct Carcharodon megalodon. To distinguish between the two hypotheses we performed several morphometric analyses. In the first analysis, we used Procrustes method and principal components analysis to quantify variation between C. carcharias, I. hastalis, and C. megalodon in four different positions within the dentition. The results indicate no significant difference in tooth shape between C. carcharias and I. hastalis. In the second analysis, correlating tooth size with age, we analyzed teeth from upper anterior and lower anterior positions. For both tooth positions, we show that the growth rate of C. carcharias is more congruent with the growth rate of I. hastalis than that of C. megalodon. Finally, we used scanning electron microscopy to show that the tooth serrations of C. carcharias are distinct from those of the megatooths and more similar in size to those of slightly serrated mako teeth. Taken together, these results indicate that C. carcharias originated from an extinct group of mako sharks and not from the megatoothed sharks.

A new species of pufferfish from the Miocene (Messinian) of Algeria is described. The single specimen available consists of a fragment of the trunk region including abdominal and caudal vertebrae, dorsal and anal fin pterygiophores, and ventral postcleithrum. It can be referred to the genus †Archaeotetraodon on the basis of its bifid scale spinules covering the preserved portion of the body. The skeletal morphology of this new species is compared to that of the previously known †Archaeotetraodon species and of selected extant tetraodontids and used to formulate hypotheses about the potential muscle arrangement in the trunk region, its significance for the functional morphology of swimming and puffing behaviour, and the possible origin of pufferfish.

The cranial anatomy of Lydekkerina huxleyi, a lydekkerinid stereospondyl from the Lower Triassic Lystrosaurus Assemblage Zone (Beaufort Group; Karoo Basin) of South Africa, is redescribed in detail following additional preparation of the poorly known holotype specimen. Whereas previous studies failed to identify any uniquely derived characteristics of L. huxleyi, three autapomorphies are identified herein: the presence of paired, anterodorsal projections within the anterior palatal vacuity, vomerine shagreen, and a series of thickened ridges on the ventral surface of the skull roof. The low ridge on the quadrate ramus of the pterygoid in L. huxleyi, previously identified as the crista obliqua homologous to that of mastodonsauroids, is reinterpreted in light of new observations on rhinesuchids. The mandible is described in detail for the first time and is shown to possess an extensive denticle shagreen on all three coronoid elements (as in primitive stereospondyls), and a distinctly elongated, prong-like arcadian process of the postglenoid area. Characters that show intraspecific variation in L. huxleyi include the contribution of the lacrimal to the narial margin, the presence of an ectopterygoid tusk, the degree of development of the transverse flange of the pterygoid, and the number of anterior meckelian foramina on the mandible. Redescription of L. huxleyi permits a reassessment of lydekkerinid species diversity in the Karoo Basin: ‘Broomulus dutoiti’ and ‘Limnoiketes paludinatans’ are regarded as subjective junior synonyms of L. huxleyi. Morphologically, Eolydekkerina magna resembles L. huxleyi more closely than had been initially suggested, and is cautiously regarded as a distinct taxon.

A new species of freshwater Testudinoidea is described from the fossil locality of Le Quesnoy (Oise, France; Argiles à Lignites du Soissonnais, Lower Eocene, Ypresian, MP7). This taxon is the oldest representative of Ptychogasteridae known from Europe. This species is compared to the American representatives of the genus Echmatemys Hay, 1906, to three Ptychogasteridae from the Geiseltal Formation (Eocene, Germany; Geiselemys ptychogastroides [Hummel, 1935], “Geoemyda” saxonica Hummel, 1935 and Hummelemys ambigua Hervet, 2004b), and to representatives of the Ptychogaster complex and to Clemmydopsis Boda, 1927. The phylogenetic relationships of this new taxon and of the other European Ptychogasteridae are studied.

The Parareptilia, the sister group to the Eureptilia, is poorly known, with many taxa in need of adequate description. One such taxon, Macroleter poezicus is found in Middle Permian strata of the Mezen River Basin in the Arkhangel'sk Province of Russia. The cranial anatomy of Macroleter is described from four new well-preserved specimens, and 89 cranial characters are incorporated into a phylogenetic analysis of parareptiles. A single most parsimonious topology is found, consisting of 205 steps, with the novel result that Macroleter is the taxon most closely related to pareiasaurs. This result has important implications for the phylogeny of the Parareptilia as well as for the identity of a disputed element (the tabular) in the skull of pareiasaurs.

A new genus and species of protorosaur is described on the basis of material originally referred to Tanystropheus antiquus from the Upper Buntsandstein of the Black Forest, Germany. The new taxon is characterized by eight cervical vertebrae that bear markedly elongate cervical ribs, a shagreen of denticles covering the vomers, palatines and pterygoids, a bifurcate second sacral rib, a well-ossified tarsus with three distal tarsals, and an elongate proximal phalanx on digit five. The status of Tanystropheus antiquus is discussed and, while it is retained, its validity is questioned.

Two juvenile specimens of the pterodactyloid pterosaur Germanodactylus cristatus are identified from the Solnhofen Limestone of southern Germany. The specimens had been referred to the nominal species Pterodactylus kochi and P. micronyx. They have edentulous tips on the upper and lower jaws; their skulls are taller and less elongate and have fewer teeth than similarly sized specimens assigned to P. antiquus and P. micronyx; and they have tall neural spines on their cervical vertebrae. In addition, they exhibit a distinctive suite of skeletal proportions that distinguishes them from similarly sized specimens assigned to P. antiquus and P. micronyx. The specimens do not exhibit any trace of a cranial crest, which supports the interpretation that the cranial crest developed late in ontogeny, probably as the individual approached skeletal and/or sexual maturity. The taxonomy of Germanodactylus is reviewed and revised diagnoses are presented.

A reexamination of the French Compsognathus corallestris, from the Portlandian lithographic limestones of the Tithonian of southern France, provides new cranial and postcranial information crucial for a better understanding of the taxon Compsognathus. The French Compsognathus is almost completely preserved either as actual bony elements or as impressions, lacking only the distal portion of its tail, and some of the manual phalanges. It is preserved in two blocks, one containing the skull and postcranial skeleton up to the seventh caudal vertebra, the other caudal vertebrae nine through 31. Compsognathids are currently known from Europe, South America, and China. The absence of an external mandibular fenestra, dorsally fan-shaped dorsal neural spines with hook-shaped ligament attachments, and a very short McI and a PhI-1, which is stouter than the radius distinguish compsognathids from other coelurosaurs. Anatomical and morphological characters of the Bavarian specimen of Compsognathus are nearly identical to those of the French specimen. The differences are related to ontogenetic or within-species variation or are caused by preservational factors. Therefore this study proposes that C. corallestris is a subjective junior synonym of Compsognathus longipes from Bavaria.

Fossils and casts of forelimb bones of the dromaeosaurids Deinonychus antirrhopus and Bambiraptor feinbergi were manually manipulated to determine range of motion and to test functional hypotheses. Shoulder motion in Bambiraptor resembles that found by a previous study on Deinonychus. The humerus can be retracted and elevated to subhorizontal positions and protracted somewhat beyond the vertical. In both taxa, the elbow can be strongly flexed but cannot be fully extended. Supination and pronation cannot occur by movement of the radius, which is immobile relative to the ulna. The palms therefore face medially except during wrist extension, which causes obligatory supination. The fingers of Deinonychus remain spread during flexion. In contrast, torsion of the distal articular surface of metacarpal I and the long axis of phalanx III-3 cause the first and third digits of Bambiraptor to approach each other during flexion, the first known instance of opposable fingers in a dinosaur. The morphology and range of motion in the forelimbs of Deinonychus and Bambiraptor enable two-handed prehension with the wrist flexed, one-handed clutching of objects to the chest, use of the hand as a hook, arm-swinging or -raising displays, and use of the forelimbs to maintain balance. Feathered wings, if present, precluded manual apprehension of objects on the ground, two-handed clutching of objects to the chest, and use of digit II to probe crevices. The forelimbs could not be used to dig. Opposability of the fingers of Bambiraptor enabled one-handed prehension, whereas Deinonychus required both hands to hold objects.

The narrow- and wide-gauge trackways attributed to sauropod dinosaurs are hypothesized to be a consequence of the relative positions of their centers of mass. This hypothesis was tested using three-dimensional, trackway- producing computer models of two sauropods and studies of Asian elephants. Centers of mass of sauropod models were computed using density distributions that reflect the high degree of pneumatization of the skeletons and air sacs within the body. A close correspondence was found between the relative areas of hand and foot prints in different trackways and the relative fractions of the body weight borne by the forefeet and hindfeet in the different types of sauropods inferred to have made the trackways. Experimental studies of Asian elephants corroborated the close correspondence between relative areas of the hindfeet and forefeet and body weight distribution. Replicating actual sauropod trackways with the walking models enabled testing of proposed gaits for a sauropod model. Brachiosaurus brancai, with its more centrally positioned center of mass, was stable and possessed a wide safety margin only when replicating a wide trackway. Conversely, Diplodocus carnegii, with a more posteriorly placed center of mass, was most stable when replicating a narrow trackway. A trend for large sauropods (>12 tons), independent of clade, to have more anteriorly positioned centers of mass was identified, and it is proposed that all large sauropods were restricted to producing wide-gauge trackways for stability reasons. The primitive gait state for Sauropodomorpha was determined to be one that produced narrow-gauge trackways.

Latest Cretaceous (Maastrichtian) terrestrial vertebrates from western North America occur in two faunal provinces. The Triceratops fauna is found in Canada, Montana, and Wyoming; and the Alamosaurus fauna occurs in Utah, New Mexico, and Texas. Although the two faunas are thought to have been contemporaneous, only the Northern Province contains intercalated volcanic units that have been isotopically dated. The first isotopic age from within the southern province is presented. A single outcrop of distal tuff within the Upper Cretaceous Javelina Formation in northern Big Bend National Park, Texas, contains monazite with a U-Pb age of 69.0 ± 0.9 Ma (2 sigma). The age is from a ²⁰⁷Pb/²⁰⁴Pb vs. ²³⁵U/²⁰⁴Pb isochron, an approach chosen to avoid the effects of ²³⁰Th-derived excess ²⁰⁶Pb. The age falls within the boundary interval between the poorly calibrated Edmontonian and Lancian North American Land Mammal Ages. The tuff bed occurs approximately in the middle of the fluvio-lacustrine Javelina Formation, about 90 m strati-graphically below the position of the Cretaceous–Tertiary boundary. This position is within the local range of the sauropod Alamosaurus, below two sites that have yielded remains of the pterosaur Quetzalcoatlus, and above a site with petrified logs of the dicotyledonous tree Javelinoxylon. The range zones of all three taxa span the full thickness of the Javelina Formation elsewhere in the Big Bend region. The Alamosaurus fauna is therefore Lancian to late Edmontonian in age.

The hadrosauroid dinosaur Pararhabdodon isonensis is known from partial cranial and postcranial material from the Maastrichtian of the south Pyrenean foredeep basin (northern Catalunya, Spain). We revise and emend the taxonomic history, stratigraphic context, osteology, and systematic position of this taxon. Our study leads us to rediagnose P. isonensis on the basis of a maxilla that combines an extremely elevated jugal joint with a subvertical and concave lateral surface of the maxilla ventral to the jugal joint, as well as a craniocaudally broad dorsal process; and a proximal half of the humerus medially offset 30° from its long axis. Our parsinomy heuristic analysis of P. isonensis and 22 other iguanodontoideans infers the phylogenetic position of the former as the sister taxon to Hadrosauridae (restricted here to the clade comprising Hadrosaurinae and Lambeosaurinae). One dentary, previously referred to P. isonensis, was collected at a site that is both stratigraphically and geographically separated from the type locality of P. isonensis. The dentary becomes the holotype of a new taxon, Koutalisaurus kohlerorum, on the basis of a uniquely elongated and medially projecting edentulous portion. This results in a distance between the symphysis and the lateral wall of the dentary that is three times the mediolateral breadth of the bone. K. kohlerorum shares with other hadrosauroids a tooth row that extends caudal to the apex of the coronoid process and, with Hadrosauridae, a tooth row that is, in occlusal view, straight and parallel to the lateral face of the dentary.

Previous descriptions of the postcranial skeleton of the primitive stegosaur Huayangosaurus taibaii (Middle Jurassic: People's Republic of China) are insufficient for character determinations in cladistic analysis. Reexamination of the postcranium has revealed several important characters, most of which are retained plesiomorphies that have not been identified previously. For example, Huayangosaurus retains ossified tendons, the loss of which has been used as a synapomorphy of Stegosauria. These purported stegosaurian synapomorphies now serve to unite the monophyletic clade Stegosauridae, defined as all stegosaurs more closely related to Stegosaurus than to Huayangosaurus. In addition, some anatomical characters previously used as ‘ankylosauromorph’ synapomorphies have now been identified in Huayangosaurus: this suggests that these characters occur more basally within Thyreophora. The plesiomorphic status of Huayangosaurus suggests that substantial convergence between ankylosaurs and stegosaurs occurred during their respective evolutionary histories, reflecting coincident functional morphological changes associated with the adoption of obligate quadrupedality.

Description of the first varanodontine varanopid material from the highly fossiliferous limestone fissure fill deposits at Richards Spur (Dolese Brothers Limestone Quarry), Oklahoma, is based on elements of at least three individuals recovered from two separate blocks of sedimentary rock. One block, which yielded associated cranial and postcranial bones from both adult and juvenile individuals, includes two well-preserved parabasisphenoid complexes, vertebrae, forelimb, pelvic girdle, and hind limb bones. An isolated maxilla fragment from another block preserves the diagnostic dorsal process characteristic of varanodontines. Preserved cranial and postcranial material is virtually identical to the varanodontine Varanops brevirostris. Taxonomic assessment of this new material in the context of the most comprehensive phylogenetic analysis of Varanopidae to date indicates the Richards Spur varanodontine is referable to Varanops brevirostris based on distinctive characters of the maxilla and the parabasisphenoid. The large size of Varanops suggests it was one of the top predators of the Richards Spur ecosystem. The Richards Spur locality records the only known co-occurrence of a mycterosaurine and a varanodontine varanopid at a single locality, and varanopids are the most common synapsids in the assemblage. As generally rare components of the more typically preserved lowland environments, the relative abundance and diversity of varanopids at Richards Spur suggests that they may have been more common components of the upland ecosystems in the Early Permian.

The early middle Miocene (MN 4a, ca 17 Ma) site of Montréal-du-Gers (France, Gers) has yielded a rich collection of land mammals. A reexamination of the listriodont material from this locality, previously attributed to Bunolistriodon lockharti, provides evidence that it consists of a new species close to the genus Eurolistriodon. Unique cranial and dental features support maintaining Eurolistriodon, which comprises two species, E. adelli and E. tenarezensis sp. nov.. A phylogenetic analysis of the European Listriodontinae, including the material from seven French localities traditionally attributed to B. lockharti, does not support the monophyly of B. lockharti. The material from the type locality of B. lockharti is closely related to Listriodon splendens, suggesting that the two genera could be synonymous.

Fossils from early Tertiary phosphate deposits of northern Mali include a new diminutive proboscidean taxon intermediate in size between Daouitherium rebouli and Phosphatherium escuilliei. Although a fragmentary specimen, it has two dentary characters previously demonstrated to be diagnostic for basal proboscideans: a labially expanded mandibular corpus in the region of m2 and m3 and a mesiolabially positioned mandibular ramus. The locality that produced the fossils, Tamaguélelt, has historically been hard to date even though it has produced many vertebrates. A section is presented that includes the locality and relates it to surrounding sediments. The locality is Eocene, lies very close to the Paleocene-Eocene boundary, and is most likely early Eocene (Ypresian). The depositional environment suggests substantial reworking of older sediments, and the fossils within them, including the proboscideans, may be even older than early Eocene. The Mali proboscidean is one of the oldest members of Afrotheria that has been found in Africa and this locality is the southernmost African early Eocene locality for mammals.

Simojovelhyus pocitosense, gen. et sp. nov., is based on a mandibular fragment with m1–3 collected from an unnamed Late Oligocene formation, in an amber mine near Simojovel, in northwestern Chiapas. The source strata consist of black, very fossiliferous, shaley phyllarenitic sandstone and mudstone that were deposited in an estuarine to swampy lagoonal environment, dated in Chrons C10–C9 (∼29.4–26.8 Ma), or early Late Oligocene. Simojovelhyus pocitosense possesses small, rectangular, bunodont molars that increase in size posteriorly. This combination of characters sets it apart from the Oligocene bunodont artiodactyls (entelodontids, tayassuids and leptochoerids), and bring it within the Helohyidae. It differs from recognized genera in having a tiny paraconid, and a unique combination of cristids and cuspulids as follows. Cristids: paracristid, anteromesocristid (neomorphic), and anterolingualcristid (neomorphic) on the trigonid anterior slope, cristid obliqua (short to remnant), and a robust postcristid in the talonid. Cuspulids (small, accessory): mesoconid, hypoconulid (large and blunt in m3), postmesoconulid (neomorphic), and pseudohypoconulid (neomorphic). This record extends the geochronologic range and geographic distribution of the Helohyidae from the Late Eocene of North America and Asia to the early Late Oligocene (Early Arikareean) of Middle America. Simojovelhyus pocitosense is also the southernmost record of Paleogene mammals, not only of Mexico, but of all North America. This record significantly adds to the meager, but important, record of Paleogene vertebrates in the tropics.