Ronan Allain

Terrestrial ecosystems from the Lower Cretaceous of Europe and bonebeds formed in swampy environments are poorly known. The Berriasian‐early Valanginian Angeac‐Charente site in France represents an example of both. Nine field campaigns have yielded thousands of fossils of over a hundred taxa, including 16 taxa from vertebrate macroremains with numerous trample and crocodile bite marks; 22 taxa from the abundant vertebrate microremains; >10 vertebrate coprolite morphotypes with plant and vertebrate inclusions; abundant sauropod and stegosaur tracks including some preserved in ‘4‐D’; termite coprolites; mollusc moulds; ostracods and plants, including coniferous wood, cones, leaves and cuticle fragments, charophytes and pollen. The richness, diversity and preservation of the fossils qualify the site as a fossil‐Lagerstätte. The site represents a ‘snapshot’ into a Lower Cretaceous ecosystem. This is supported by REE analyses of biogenic apatite and sediment samples, the fossils being found in a single stratigraphical interval and the record of sedimentological and taphonomic ‘frozen scenes’. The Angeac‐Charente bonebed is highly diverse, dominated by an ornithomimosaur taxon, and contains both macro‐ and microfossils. This indicates a complex formation, likely primarily influenced by ecological and biologic processes, but also significant physical processes. These include crocodyliform predation and/or scavenging on turtles, ornithomimosaurs and fishes; probable mass mortality occurrence of an ornithomimosaur herd; possible social behaviour of stegosaurs; limited hydraulic transport of most sauropod bones and intense dinoturbation.

Brachiosauridae is a clade of titanosauriform sauropod dinosaurs that includes the well-known Late Jurassic taxaBrachiosaurusandGiraffatitan. However, there is disagreement over the brachiosaurid affinities of most other taxa, and little consensus regarding the clade’s composition or inter-relationships. An unnamed partial sauropod skeleton was collected from middle–late Oxfordian (early Late Jurassic) deposits in Damparis, in the Jura department of eastern France, in 1934. Since its brief description in 1943, this specimen has been informally known in the literature as the ‘Damparis sauropod’ and ‘FrenchBothriospondylus’, and has been considered a brachiosaurid by most authors. If correctly identified, this would make the specimen the earliest known titanosauriform. Coupled with its relatively complete nature and the rarity of Oxfordian sauropod remains in general, this is an important specimen for understanding the early evolution of Titanosauriformes. Full preparation and description of this specimen, known from teeth, vertebrae and most of the appendicular skeleton of a single individual, recognises it as a distinct taxon:Vouivria damparisensisgen. et sp. nov. Phylogenetic analysis of a data matrix comprising 77 taxa (including all putative brachiosaurids) scored for 416 characters recovers a fairly well resolved Brachiosauridae.Vouivriais a basal brachiosaurid, confirming its status as the stratigraphically oldest known titanosauriform. Brachiosauridae consists of a paraphyletic array of Late Jurassic forms, withEuropasaurus,VouivriaandBrachiosaurusrecovered as successively more nested genera that lie outside of a clade comprising (Giraffatitan+Sonorasaurus) + (Lusotitan+ (Cedarosaurus+Venenosaurus)).Abydosaurusforms an unresolved polytomy with the latter five taxa. The Early Cretaceous South American sauropodPadillasauruswas previously regarded as a brachiosaurid, but is here placed within Somphospondyli. A recent study contended that a number of characters used in a previous iteration of this data matrix are ‘biologically related’, and thus should be excluded from phylogenetic analysis. We demonstrate that almost all of these characters show variation between taxa, and implementation of sensitivity analyses, in which these characters are excluded, has no effect on tree topology or resolution. We argue that where there is morphological variation, this should be captured, rather than ignored. Unambiguous brachiosaurid remains are known only from the USA, western Europe and Africa, and the clade spanned the Late Jurassic through to the late Albian/early Cenomanian, with the last known occurrences all from the USA. Regardless of whether their absence from the Cretaceous of Europe, as well as other regions entirely, reflects regional extinctions and genuine absences, or sampling artefacts, brachiosaurids appear to have become globally extinct by the earliest Late Cretaceous.

International audienceSpinosaurs represent a group of peculiar theropod dinosaurs that have often been described as “crocodile-mimic”, predominantly fish-eating predators, and recently claimed to have been semi-aquatic animals. Here we report a suite of craniodental characters unexpectedly shared by spinosaurs and pike conger eels. Pike conger eels are predatory, mainly piscivorous bottom-dwelling anguilliform fishes that inhabit marine and brackish environments. These two groups of dinosaurs and fishes show a mediolaterally compressed, elongated rostrum, a terminal “rosette” bearing enlarged teeth in both upper and lower jaws, and a notch posterior to the premaxillary “rosette” characterized by the presence of reduced teeth. The morphological convergence observed in the jaws of these two distantly related groups of vertebrates may result from similar feeding behaviours. This typical jaw morphology likely represents an effective biomechanical adaptation for biting and grabbing elusive prey items in low-light aquatic environments. Associated with this specialized snout morphology, numerous integumentary mechanoreceptors involved in prey detection are present in both spinosaurs and pike congers. Our new observations provide an additional convincing argument regarding the decades-long and widely debated lifestyle of spinosaurs

Spinosaurids are among the largest and most specialized carnivorous dinosaurs. The morphology of their crocodile-like skull, stomach contents, and oxygen isotopic composition of the bones suggest they had a predominantly piscivorous diet. Even if close relationships between spinosaurids and Middle Jurassic megalosaurs seem well established, very little is known about the transition from a generalized large basal tetanuran to the specialized morphology of spinosaurids. Spinosaurid remains were previously known from the Early to Late Cretaceous of North Africa, Europe, and South America. Here, we report the discovery of a new spinosaurid theropod from the late Early Cretaceous Savannakhet Basin in Laos, which is distinguished by an autapomorphic sinusoidal dorsosacral sail. This new taxon, Ichthyovenator laosensis gen. et sp. nov., includes well-preserved and partially articulated postcranial remains. Although possible spinosaurid teeth have been reported from various Early Cretaceous localities in Asia, the new taxon I. laosensis is the first definite record of Spinosauridae from Asia. Cladistic analysis identifies Ichthyovenator as a member of the sub-clade Baryonychinae and suggests a widespread distribution of this clade at the end of the Early Cretaceous. Chilantaisaurus tashouikensis from the Cretaceous of Inner Mongolia, and an ungual phalanx from the Upper Jurassic of Colorado are also referred to spinosaurids, extending both the stratigraphical and geographical range of this clade.

Poekilopleuron bucklandii, described by Eudes–Deslongchamps in 1838, is one of the earliest discovered dinosaurs. Although incomplete, it is one of the best preserved Middle Jurassic theropods known from Europe. Unfortunately, the only specimen of P. bucklandii, housed in the Musée de la Faculté des Sciences de Caen, was destroyed during World War II. However, casts of some parts of the type skeleton have been found in the collections of the Museum National d’Histoire Naturelle, Paris. These casts and Eudes–Deslongchamps’ monograph are used to redescribe the specimen. Poekilopleuron shares one synapomorphy with the Spinosauroidea and we tentatively assign it to that clade. The possible synonymy between Poekilopleuron and Megalosaurus is examined and we conclude that Megalosaurus is a nomen dubium and that the name should be restricted to the type dentary.