Anatomy of Juravenator starki (Theropoda: Coelurosauria) from the Late Jurassic of Germany
Chiappe, Luis M.; Göhlich, Ursula B.
published: Dec 1, 2010
ArtNo. ESP155025803001, Price: 29.00 €
We provide a detailed study of the morphology of the holotype of Juravenator starki from the Late Jurassic of the Solnhofen area of southern Germany. The incompletely ossified surface of multiple bones and lack of several skeletal fusions indicate that Juravenator starki is based on an immature specimen. Nonetheless, numerous unique morphologies and bone proportions distinguish this taxon from Compsognathus longipes, the only previously named non-avian theropod dinosaur from the Late Jurassic of the Solnhofen Archipelago. Yet, its skeletal anatomy is most similar to that of Compsognathus and other theropods that have often been regarded as closely related to the latter - sometimes within a monophyletic Compsognathidae. Juravenator is characterized by having a small size (∼ 0.75-meter-long in the holotype) with few maxillary teeth, lack of a premaxillary-maxillary diastema, an antorbital fenestra subequal in length to orbit, an elongate scapula that is narrowest at its neck, a proportionally short humerus and high and abruptly tapered manual claws, and bow-like zygapophysial articulations in the mid-caudal vertebrae. Portions of the epidermis preserved mainly along the tail provide the only glimpse of the morphology of the skin of basal coelurosaurs, and structures newly revealed under UV light hint at the possibility of filamentous integumentary structures - akin to those interpreted as proto-feathers in other basal coelurosaurs - also covering the body of this dinosaur. The discovery of Juravenator has provided evidence of morphologies - from details of the skull to the epidermis - that are poorly known in other theropods interpreted as at or near the base of Coelurosauria, and thus contributes significantly to our understanding of the evolutionary history of this clade. The exquisitely preserved holotipic skeleton adds significantly to the meager record of small-bodied Late Jurassic theropods.