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DESCRIPTION OF A NEW SPECIMEN OF AN ANHANGUERID (PTEROSAURIA, PTERODACTYLOIDEA) FROM THE ROMUALDO FORMATION, ARARIPE BASIN (LOWER CRETACEOUS, NORTHEASTERN BRAZIL)
Última alteração: 2019-09-29
Resumo
Pterosaurs, flying reptiles that lived during the Mesozoic era, were the first vertebrates to develop powered flight. Despite being patchy, the pterosaur fossil record extends worldwide, including Brazil, where they are well represented in the Araripe Basin. The Romualdo Formation (Aptian-Albian) of the Santana Group of this basin, a Konservat Lagerstätten rich in calcareous concretions, has yielded several exceptionally well-preserved pterosaur fossils. MN 4727-V, one of these, consists of three-dimensionally preserved post-cranial elements, namely: right humerus, proximal portion of right ulna and radius, left scapula, part of the right scapula, right coracoid and proximal portion of the left one, right femur, notarium, dorsal, cervical, sacral and caudal vertebrae, sternum, ribs, pubes, ischia and illia. MN 4727 - V is a pteranodontoid since it exhibits an enlarged, warped deltopectoral crest, and the shape of the distal articulation of its humerus is subtriangular. Based on the fact that the scapula is substantially shorter than the coracoid (sca/co < 0.80), MN 4727-V is nested within the Anhangueridae. The specimen bears evidence of being a juvenile (e.g not presenting a fused scapulocoracoid). Unlike Anhanguera piscator and AMNH 22555, both from the Romualdo Formation and lacking a notarium, the last cervical and the first five dorsal vertebrae compose the notarium of MN 4727-V, which, despite having the same number of notarial vertebrae, differs from that of Anhanguera spielbergi by not being as strongly fused. The sacral vertebrae of MN 4727-V seem to be in a more advanced stage of fusion than those of A. piscator, which is evidenced by the contact between second and third sacrals, and the degree of fusion of sacral processes. The wingspan of MN 4727-V was estimated to be about 3.9 meters. Besides adding knowledge on anhaguerids, this new specimen reinforces the importance and the potential of the Araripe Basin in providing exceptional fossils. [UFABC, MN, CNPQ].