Osteology of an exceptionally well-preserved tapejarid skeleton from Brazil: Revealing the anatomy of a curious pterodactyloid clade

Abstract

A remarkably well-preserved, almost complete and articulated new specimen (GP/2E 9266) of Tupandactylus navigans is here described for the Early Cretaceous Crato Formation of Brazil. The new specimen comprises an almost complete skeleton, preserving both the skull and post-cranium, associated with remarkable preservation of soft tissues, which makes it the most complete tapejarid known thus far. CT-Scanning was performed to allow the assessment of bones still covered by sediment. The specimen can be assigned to Tupa. navigans due to its vertical supra-premaxillary bony process and short and rounded parietal crest. It also bears the largest dentary crest among tapejarine pterosaurs and a notarium, which is absent in other representatives of the clade. The new specimen is here regarded as an adult individual. This is the first time that postcranial remains of Tupa. navigans are described, being also an unprecedented record of an articulated tapejarid skeleton from the Araripe Basin.

A new specimen ofSinopterus dongi(Pterosauria, Tapejaridae) from the Jiufotang Formation (Early Cretaceous, China)

“…A distinct foramen is present on the ventral proximal end of the humerus, close (slightly distal to) the humeral head, between the deltopectoral and ulnar crests. This is similar to other azhdarchoids in general, as can be seen in Tapejara wellnhoferi ( Eck, Elgin & Frey, 2011 ), Caiuajara dobruskii ( Manzig et al, 2014 ), Tupandactylus navigans ( Beccari et al, 2021 ), Caupedactylus ybaka ( Kellner, 2013 ), Tupuxuara leonardii ( Kellner & Hasegawa, 1993 ), Keresdrakon vilsoni ( Kellner et al, 2019 ), and azhdarchids ( Lawson, 1975 ; Hone, Habib & Therrien, 2019 ). The humeral shaft slightly expands towards the distal end.…”

“…It forms an approximately perpendicular angle relative to the main shaft. This is similar to Caupedactylus ybaka ( Kellner, 2013 ) and Tupuxuara leonardii ( Witton, Martill & Green, 2009 ), and slightly different from Tapejara wellnhoferi , Caiuajara dobruskii and Tupandactylus navigans , in which the deltopectoral crest is at a slightly oblique angle to the humeral shaft, ventromedially oriented ( Eck, Elgin & Frey, 2011 ; Manzig et al, 2014 ; Beccari et al, 2021 ). The region of the humeral head, in ventral view, is marked by a triangular eminence.…”

“…This last character is absent in other azhdarchoids such as Caupedactylus ( Kellner, 2013 ), Tupuxuara ( Witton, Martill & Green, 2009 ) and azhdarchids ( Witton, Martill & Green, 2009 ) in which the ulnar crest is trapezoidal and posteriorly oriented, and this feature is thus of potential phylogenetic relevance for tapejarines. Furthermore, Sinopterus dongi differs from Tapejara , Caiuajara and Tupandactylus in exhibiting a deltopectoral crest of the humerus which is perpendicular to the humeral shaft, while in Tapejara , Caiuajara and Tupandactylus it is slightly oblique, slanting proximally ( Eck, Elgin & Frey, 2011 ; Manzig et al, 2014 ; Beccari et al, 2021 ; see also Fig. 9 ).…”

“… Pan et al, 2013 ; Xu et al, 2020 ) and many other pterosaur remains from around the world ( e.g. , Beccari et al, 2021 ). This frequent preservation style in pterosaurs turns anatomical comparisons relatively hard, since it limits what bone surfaces can, or not, be viewed ( e.g.…”

A new wing skeleton of the Jehol tapejarid Sinopterus and its implications for ontogeny and paleoecology of the Tapejaridae

“…Terminally, the crest is slightly expanded and forms a small distal prominence. This prominence is not known in other tapejarids 6 , 29 – 32 . The ulnar crest is damaged and lacks available information.…”