Redescription of Cearadactylus atrox (Pterosauria, Pterodactyloidea) from the Early Cretaceous Romualdo Formation (Santana Group) of the Araripe Basin, Brazil

ABSTRACT

Based on one of the first cranial pterosaur specimens unearthed from the Romualdo Formation (Araripe Basin), Cearadactylus atrox has caused disagreement among paleontologists regarding its relationships. Ranging from an ornithocheirid, an indeterminated pterodactyloid, to a ctenochasmatid, some authors even regarded this species as representing a distinct suprageneric clade. Further preparation of the holotype that was transferred to the collections of the Museu Nacional/UFRJ (MN 7019-V) revealed several new features allowing a redescription and reevaluation of the phylogenetic position of this species. Among the new observations, it is clear that the rostral end of this specimen had been glued to the skull, rendering previous anatomical interpretations incorrect. There is no rostral gap, and the expanded rostral end of the premaxillae is larger than the dentary, rather than smaller. Cearadactylus atrox is here considered a valid taxon that can be diagnosed by a dentary groove that bifurcates at the rostral end, orbit and naris in a high position relative to the nasoantorbital fenestra, and a comparatively small number of teeth (32–36 maxillary, 22–26 mandibular), decreasing in size towards the posterior end. Phylogeneticaly, it is placed as the sister group of the Anhangueridae, forming a large clade of Brazilian forms (Tropeognathus and Anhanguera), which has a European taxon (‘Ornithocheirus’ compressirostris) as its sister group.

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ACKNOWLEDGMENTS

We would like to thank H. P. Silva and J. Pontes (MN/UFRJ) for great help during preparation of the specimen; G. Oliveira (UFRPE), P. Romano (UFV), T. Rodrigues (UFES), and F. Nunes (MN/UFRJ) for discussions regarding pterosaurs and phylogeny; L. Facó for specimen photography; M. Massarani (FFCLRP/USP) for drawings; and M. Barbosa for figure editing. TNT is made available with the sponsorship of the Willi Hennig Society. C. Bennett, editor H.-L. You, and an anonymous referee greatly improved the manuscript. Also we would like to thank the Pró-reitoria de Pesquisa e Pós- Graduação (PROPESQ proc. UFPE 23076.027497/2010-13 to J.M.S.), FAPERJ (nos. E-26/111.273/2010 and E-26/102.737/2012 to A.W.A.K.), and CNPq (no. 307276/2009-0 to A.W.A.K.). This research was partially funded by CAPES (Masters fellowship to B.C.V.N.)

Handling editor: Hailu You