The Rhynchocephalians are the sister group to the Squamates (Snakes and Lizards), the two groups having derived during the Early Triassic. Today only a single member of this group survives, the Tuatara, Sphenodon punctatus, that was once found across New Zealand, but is now only found on offshore islands where Mammals and Squamates have not been introduced, which has led to speculation that the group were generally unable to cope with such competition. However the group has a long fossil record, which includes a diverse range of groups, including hoofed running animals, armoured forms, and an aquatic group, the Pleurosaurs, which suggests that the group were highly adaptable in the past, and unlikely to have died out due to competition from other groups.
In a paper published in the journal Royal Society Open Science on 8 November 2017, Gabriel Bever of the Center for Functional Anatomy and Evolution at the Johns Hopkins University School of Medicine, and the Division of Paleontology at the American Museum of Natural History, and Mark Norell, also of the Division of Paleontology at the American Museum of Natural History, describe a new species of Rhynchocephalian from the Late Jurassic Solhofen of Bavaria, Germany.
The new species is named Vadasaurus herzogi, where 'Vadasaurus' means 'wading Lizard' and 'herzogi' honours Bavarian film-maker Werner Herzog. The species is described from a single specimen preserved as an articulated skeleton on a slab of limestone. This species is interpreted as having has a semi-aquatic lifestyle. and was recovered by a phylogenetic analysis as being closely related to, but outside, the aquatic Pleurosaurs.
Holotype of Vadasaurus herzogi collected from the Late Jurassicmarine limestones of Solnhofen, Bavaria. The skull, forelimbs, and first 18 presacral vertebrae and ribs are exposed in the dorsal or dorsolateral view. Posteriorly, the skeleton is rotated approximately 180°, making it visible largely in the ventral view. Left hindlimb is exposed in the dorsal view. Anatomical abbreviations: As, astragalus; Ca, calcaneum; Cdv, caudal vertebra; Co, coracoid; Cr, cervical rib; Cv, cervical vertebra; D, dentary; Dv, dorsal vertebra; F, femur; Fb, fibula; Fr, frontal; Ga, gastralia; H, humerus; I, intermedium; Is, ischium; l, left; Mc, metacarpal; Mt, metatarsal; Mx, maxilla; Ph, phalanx; Pu, pubis; R, radius; r, right; S, scapula; Sc, sternal cartilage; Ss, suprascapular cartilage; Sv, sacral vertebra; T, tibia; U, ulna. Bever & Norell.
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