An agile unarmored notosuchian from Cenomanian-age rocks in Niger initiate he partinioning of the Gondwanan plexus of Araripesuchus species

SERENO, P.C.; POL, D.

Congreso; 79° Annual Meeting of the Society of Vertebrate Paleontology; 2019

A new slender-limbed notosuchian is described from Cenomanian-age rocks in Niger. The single, and only known, adult specimen preserves in articulation the cranium and lower jaw, the axial column to the mid dorsal vertebrae, and the pectoral girdle and most of the forelimb. More posterior portions of the axial column including sacral and caudal vertebrae and portions of the the pelvic girdle and both hind limbs suggest that the skeleton was very complete and articulated when originally buried. However, not a single osteoderm is preserved, and the cranium, furthermore, lacks the pitted texturing that characterizes nearly all other crocodylomorphs. The new taxon is allied with Araripesuchus tsangatsangana from Madagascar, and has the same paleogeographic link to Madagascar as its contemporary, the fanged Kaproscuhus. The Malagasy araripesuchid, furthermore, also shows little evidence of dorsal osteoderms, despite the recovery of multiple, semi- articulated specimens from a single locality as well as the presence in the same formation of Simosuchus with its extraordinary osteoderm sheathing. We reconstruct the new species as one of the most erect, long-limbed notosuchians of all, a striking departure from the previous reconstruction of A. tsangatsangana as semi-erect with a full compliment of parasagittal dorsal osteoderms. The new species, as well as additional remains of the older A. wegneri from Niger, provide new evidence to tease apart the paraphyletic assemblage of Gondwanan species currently assigned to Araripesuchus.