Maniraptora includes birds and their closest relatives among theropod dinosaurs. During the Cretaceous period, several maniraptoran lineages diverged from the ancestral coelurosaurian bauplan and evolved novel ecomorphologies, including active flight, gigantism, cursoriality and herbivory. Propagation X-ray phase-contrast synchrotron microtomography of a well-preserved maniraptoran from Mongolia, still partially embedded in the rock matrix, revealed a mosaic of features, most of them absent among non-avian maniraptorans but shared by reptilian and avian groups with aquatic or semiaquatic ecologies. This new theropod, Halszkaraptor escuilliei gen. et sp. nov., is related to other enigmatic Late Cretaceous maniraptorans from Mongolia in a novel clade at the root of Dromaeosauridae. This lineage adds an amphibious ecomorphology to those evolved by maniraptorans: it acquired a predatory mode that relied mainly on neck hyperelongation for food procurement, it coupled the obligatory bipedalism of theropods with forelimb proportions that may support a swimming function, and it developed postural adaptations convergent with short-tailed birds.

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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.

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

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. Institutional abbreviations. CMNH, Colorado MuseumType genus. Elasmosaurus Cope, 1868.Emended diagnosis. Weakly excavated ventral cheek margin; palate without anterior pterygoid vacuities; platycoelous vertebral articular surfaces; more than 40 cervical vertebrae; cervical centra longer than high; lateral keel in mid-anterior cervical vertebrae. For a characterization of elasmosaurids see Brown (1993). Genus OCCITANOSAURUS gen. nov.Derivation of name. From Occitania, the area where the Occitan language is spoken (currently includes most of southern France, Val d'Aran of Spain and several Piedmont valleys of Italy) and Sauros (Greek): lizard. Sciau, Crochet and Mattei, 1990 Diagnosis. As for type and only species of the genus, Occitanosaurus tournemirensis (Sciau, Crochet and Mattei, 1990). Type species. Plesiosaurus tournemirensis