Pascal Godefroit

a new elasmosaurid plesiosaur from the Lower Jurassic of southern France

Plesiosaurus tournemirensis Sciau, Crochet and Mattei, based on a nearly complete skeleton with skull from the Upper Toarcian (Lower Jurassic) of Tournemire (Aveyron Department, southern France), is here redescribed and reinterpreted. Comparisons with other plesiosaurs indicate that it belongs to a new genus, Occitanosaurus. O. tournemirensis is characterized mainly by its spatulate premaxillae with short facial process, very high postorbital broadly contacting posterior ramus of the maxilla, trapezoidal jugal excluded from orbital margin, orbit diagonally oriented, temporal fenestra with a sigmoidal anterior margin, 43 cervical vertebrae, powerful interclavicle-clavicle complex and coracoids with a pointed protuberance on lateral border and expanded posterolateral cornua. Cranial and cervical vertebra features show that this new genus is undoubtedly a representative of the Elasmosauridae. A preliminary cladistic analysis of long-necked plesiosaurs reveals that, within Elasmosauridae, Occitanosaurus is a close relative of Microcleidus and Muraenosaurus.

A Jurassic avialan dinosaur from China resolves the early phylogenetic history of birds.

The recent discovery of small paravian theropod dinosaurs with well-preserved feathers in the Middle–Late Jurassic Tiaojishan Formation of Liaoning Province (northeastern China) has challenged the pivotal position of Archaeopteryx, regarded from its discovery to be the most basal bird. Removing Archaeopteryx from the base of Avialae to nest within Deinonychosauria implies that typical bird flight, powered by the forelimbs only, either evolved at least twice, or was subsequently lost or modified in some deinonychosaurians. Here we describe the complete skeleton of a new paravian from the Tiaojishan Formation of Liaoning Province, China. Including this new taxon in a comprehensive phylogenetic analysis for basal Paraves does the following: (1) it recovers it as the basal-most avialan; (2) it confirms the avialan status of Archaeopteryx; (3) it places Troodontidae as the sister-group to Avialae; (4) it supports a single origin of powered flight within Paraves; and (5) it implies that the early diversification of Paraves and Avialae took place in the Middle–Late Jurassic period.

A complete skull of Allodaposuchus precedens Nopcsa, 1928 (Eusuchia) and a reassessment of the morphology of the taxon based on the Romanian remains

Abstract A new eusuchian skull from the Maastrichtian locality of Oarda de Jos in the southwestern Transylvanian Basin of Romania represents the best-preserved known specimen of Allodaposuchus precedens Nopcsa, 1928. This new fossil allows us to clearly characterize the skull morphology of A. precedens and to reject the idea, as recently suggested, that the taxon could be considered a nomen dubium. Parsimony analysis confirms earlier phylogenetic hypotheses based on the fragmentary holotype from the Maastrichtian of Valioara in Haţeg Basin (Romania), as well as on putative conspecific remains from approximately coeval localities in Spain and France: A. precedens is a non-crocodylian eusuchian. However, some relevant morphological traits differ from what was previously reported for this taxon: the external naris is large and anterodorsally directed; the lateral profile of the skull is not festooned in dorsal view; the suborbital fenestrae reach the eighth alveolus; the postorbital bar is not massive and inset from the jugal margin; the skull table is approximately planar or medially concave and does not markedly overhang the supratemporal fenestrae; the exoccipitals are not significantly involved in the basioccipital tubera. Because the condition of most of these characters was unknown in the holotype, the morphology of the taxon was previously evaluated on non-Romanian remains only. The morphological discrepancies between Romanian and western European fossils could suggest the presence of different taxa, possibly of infra-generic rank. Allodaposuchus and presumably Hylaeochampsa are the only eusuchians showing a laterally open cranioquadrate passage.

New Hadrosaurid Dinosaurs from the Uppermost Cretaceous of Northeastern China

Several hundred disarticulated dinosaur bones have been recovered from a large quarry at Wulaga (Heilongjiang Province, China), in the Upper Cretaceous (Maastrichtian) Yuliangze Formation. The Wulaga quarry can be regarded as a monodominant bonebed: more than 80% of the bones belong to a new lambeosaurine hadrosaurid, Sahaliyania elunchunorum gen. et sp. nov. This taxon is characterised by long and slender paroccipital processes, a prominent lateral depression on the dorsal surface of the frontal, a quadratojugal notch that is displaced ventrally on the quadrate, and a prepubic blade that is asymmetrically expanded, with an important emphasis to the dorsal side. Phylogenetic analysis shows that Sahaliyania is a derived lambeosaurine that forms a monophyletic group with the corythosaur and parasauroloph clades. Nevertheless, the exact position of Sahaliyania within this clade cannot be resolved on the basis of the available material. Besides Sahaliyania, other isolated bones display a typical hadrosaurine morphology and are referred to Wulagasaurus dongi gen. et sp. nov., a new taxon characterised by the maxilla pierced by a single foramen below the jugal process, a very slender dentary not pierced by foramina, and by the deltopectoral crest (on the humerus) oriented cranially. Phylogenetic analysis indicates that Wulagasaurus is the most basal hadrosaurine known to date. Phylogeographic data suggests that the hadrosaurines, and thus all hadrosaurids, are of Asian origin, which implies a relatively long ghost lineage of approximately 13 million years for basal hadrosaurines in Asia.

A remarkable hollow-crested hadrosaur from Russia: an Asian origin for lambeosaurines

The nearly complete skeleton of a new lambeosaurine dinosaur, Olorotitan arharensis, has been discovered in the Maastrichtian Tsagayan Formation at Kundur, Far Eastern Russia. This is the most complete dinosaur skeleton ever discovered in Russia and, with its finely preserved supracranial crest, the most complete lambeosaurine outside North America. This new taxon is remarkable by the unusual shape of its hollow crest and by the important elongation of its neck and of its sacrum. An additional articulation between adjacent neural spines made the proximal third of the tail rigid, but it cannot be excluded that it is a pathological feature. Phylogenetic analysis shows that Olorotitan is the sister-taxon of the North American genera Corythosaurusand Hypacrosaurus. Lambeosaurines originated from Asia and then migrated to North America before or at the

A new Barremian (Early Cretaceous) ichthyosaur from western Russia

ABSTRACT A new ophthalmosaurid ichthyosaur, Sveltonectes insolitus, gen. et sp. nov., is described from a sub-complete and three-dimensionally preserved specimen from the late Barremian of western Russia. This new taxon is supported by 11 cranial, dental, and postcranial autapomorphies, and is also characterized by features previously considered as autapomorphic for some other Ophthalmosauridae, such as a processus narialis on the prefrontal and relatively long hind fins with pre- and postaxial accessory digits. We conducted a new phylogenetic analysis of Thunnosauria, which supports a ‘Stenopterygius’ origin for Ophthalmosauridae. Sveltonectes is regarded as the sister taxon of Aegirosaurus, which shares a similar skull roof construction. Contrary to most other Cretaceous ichthyosaurs, Sveltonectes is characterized by delicate and sharply pointed teeth, confirming that the ophthalmosaurids were ecologically highly diversified during the Early Cretaceous.

A Jurassic ornithischian dinosaur from Siberia with both feathers and scales

Feathers, not just for the birds? Theropod dinosaurs, thought to be the direct ancestors of birds, sported birdlike feathers. But were they the only feathery dino group? Godefroit et al. describe an early neornithischian dinosaur with both early feathers and scales. This seemingly feathery nontheropod dinosaur shows that feathers were not unique to the ancestors of birds and may even have been quite widespread. Science, this issue p. 451 A fossil dinosaur with primitive feathers and scales suggests that feathers may have been present across dinosaur clades. Middle Jurassic to Early Cretaceous deposits from northeastern China have yielded varied theropod dinosaurs bearing feathers. Filamentous integumentary structures have also been described in ornithischian dinosaurs, but whether these filaments can be regarded as part of the evolutionary lineage toward feathers remains controversial. Here we describe a new basal neornithischian dinosaur from the Jurassic of Siberia with small scales around the distal hindlimb, larger imbricated scales around the tail, monofilaments around the head and the thorax, and more complex featherlike structures around the humerus, the femur, and the tibia. The discovery of these branched integumentary structures outside theropods suggests that featherlike structures coexisted with scales and were potentially widespread among the entire dinosaur clade; feathers may thus have been present in the earliest dinosaurs.

Reduced plumage and flight ability of a new Jurassic paravian theropod from China.

Feathered theropods were diverse in the Early Cretaceous Jehol Group of western Liaoning Province, China. Recently, anatomically distinct feathered taxa have been discovered in the older Middle-Late Jurassic Tiaojishan Formation in the same region. Phylogenetic hypotheses including these specimens have challenged the pivotal position of Archaeopteryx in bird phylogeny. Here we report a basal troodontid from the Tiaojishan Formation that resembles Anchiornis, also from Jianchang County (regarded as sister-taxa). The feathers of Eosinopteryx are less extensive on the limbs and tail than Anchiornis and other deinonychosaurians. With reduced plumage and short uncurved pedal claws, Eosinopteryx would have been able to run unimpeded (with large foot remiges cursorial locomotion was likely problematic for Anchiornis). Eosinopteryx increases the known diversity of small-bodied dinosaurs in the Jurassic, shows that taxa with similar body plans could occupy different niches in the same ecosystem and suggests a more complex picture for the origin of flight.

A basal thunnosaurian from Iraq reveals disparate phylogenetic origins for Cretaceous ichthyosaurs

Cretaceous ichthyosaurs have typically been considered a small, homogeneous assemblage sharing a common Late Jurassic ancestor. Their low diversity and disparity have been interpreted as indicative of a decline leading to their Cenomanian extinction. We describe the first post-Triassic ichthyosaur from the Middle East, Malawania anachronus gen. et sp. nov. from the Early Cretaceous of Iraq, and re-evaluate the evolutionary history of parvipelvian ichthyosaurs via phylogenetic and cladogenesis rate analyses. Malawania represents a basal grade in thunnosaurian evolution that arose during a major Late Triassic radiation event and was previously thought to have gone extinct during the Early Jurassic. Its pectoral morphology appears surprisingly archaic, retaining a forefin architecture similar to that of its Early Jurassic relatives. After the initial latest Triassic radiation of early thunnosaurians, two subsequent large radiations produced lineages with Cretaceous representatives, but the radiation events themselves are pre-Cretaceous. Cretaceous ichthyosaurs therefore include distantly related lineages, with contrasting evolutionary histories, and appear more diverse and disparate than previously supposed.

Taphonomy and Age Profile of a Latest Cretaceous Dinosaur Bone Bed in Far Eastern Russia

Abstract A large dinosaur bone bed has been investigated in the Udurchukan Formation (?late Maastrichtian) at Blagoveschensk, Far Eastern Russia. The observed mixture of unstratified fine and coarse sediments in the bone bed is typical for sediment-gravity-flow deposits. It is postulated that sediment gravity flows, originating from the uplifted areas at the borders of the Zeya-Bureya Basin, reworked the dinosaur bones and teeth as a monodominant bone bed. Fossils of the lambeosaurine Amurosaurus riabinini form >90% of the recovered material. The low number of associated skeletal elements at Blagoveschensk indicates that the carcasses were disarticulated well before reworking. Although shed theropod teeth have been found in the bone bed, <2% of the bones exhibit potential tooth marks; scavenging activity was therefore limited, or scavengers had an abundance of prey at hand and did not have to actively seek out bones for nutrients. Perthotaxic features are very rare on the bones, implying that they were not exposed subaerially for any significant length of time before reworking and burial. The underrepresentation of light skeletal elements, the dislocation of the dental batteries, and the numerous fractured long bones suggest that most of the fossils were reworked. The random orientation of the elements might indicate a sudden end to transport before stability could be reached. The size-frequency distributions of the femur, tibia, humerus, and dentary elements reveal an overrepresentation of late juveniles and small subadult specimens, indicative of an attritional death profile for the Amurosaurus fossil assemblage. It is tentatively postulated that the absence of fossils attributable to nestling or early juvenile individuals indicates that younger animals were segregated from adults and could join the herd only when they reached half of the adult size.