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Concept
Dorygnathus
Résumé
Dorygnathus ("spear jaw") was a genus of rhamphorhynchid pterosaur that lived in Europe during the Early Jurassic period, when shallow seas flooded much of the continent. It had a short () wingspan, and a relatively small triangular sternum, which is where its flight muscles attached. Its skull was long and its eye sockets were the largest opening therein. Large curved fangs that "intermeshed" when the jaws closed featured prominently at the front of the snout while smaller, straighter teeth lined the back. Having two or more morphs of teeth, a condition called heterodonty, is rare in modern reptiles but more common in basal ("primitive") pterosaurs. The heterodont dentition in Dorygnathus is consistent with a piscivorous (fish-eating) diet. The fifth digit on the hindlimbs of Dorygnathus was unusually long and oriented to the side. Its function is not certain, but the toe may have supported a membrane like those supported by its wing-fingers and pteroids. Dorygnathus was according to David Unwin related to the Late Jurassic pterosaur Rhamphorhynchus and was a contemporary of Campylognathoides in Holzmaden and Ohmden.
The first remains of Dorygnathus, isolated bones and jaw fragments from the Schwarzjura, the Posidonia Shale dating from the Toarcian, were discovered near Banz, Bavaria and in 1830 described by Carl Theodori as Ornithocephalus banthensis; the specific name referring to Banz. In 1831 however, Theodori reassigned the species to the genus Pterodactylus, therefore creating P. banthensis. The holotype, a lower jaw, is specimen PSB 757. The fossils were studied by Christian Erich Hermann von Meyer in 1831 and again by Theodori in 1852 when he referred them to the genus Rhamphorhynchus instead of Pterodactylus. In this period a close affinity was assumed with a pterosaur known from Britain, later named Dimorphodon. Some fossils were sent to a professor of paleontology in Munich named Johann Andreas Wagner.
Source officielle
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