ISOLATED ARCHOSAURIAN TEETH FROM “LA BONITA” LOCALITY (LATE CRETACEOUS, SANTONIAN-CAMPANIAN), RÍO NEGRO PROVINCE, ARGENTINA.

GIANECHINI, FEDERICO A.; LIO, GABRIEL; APESTEGUIA, S.

Historia Natural

Fundacion Felix de Azara

Lugar: Buenos Aires; Año: 2011 vol. 3 p. 5 - 16

0326-1778

The tetrapod assemblage of the Bajo de la Carpa Formation (Late Cretaceous; Santonian-early Campanian) is dominated by archosaurs, represented by saurischians, such as alvarezsaurid, enanthiornithine, and abelisauroid theropods (e.g. Velocisaurus unicus Bonaparte, 1991) and titanosaurs (e.g. Bonitasaura salgadoi Apesteguía, 2004), as well as crocodyliform remains which are the most abundant specimens (e.g. Notosuchus terrestris Woodward, 1896). Here we report new archosaur remains from the Bajo de la Carpa Formation at the ‘La Bonita’ locality, consisting of isolated shed teeth. Two of these specimens present a crown with a straight distal border and denticles with shape and density similar to that observed in abelisaurid theropods. A third tooth is more distally curved, without mesial denticles, and with a figure eight-shaped basal cross-section, resembling the dental features described for the basal tetanuran Orkoraptor burkei Novas, Ezcurra and Lecuona, 2008, but differing from this theropod due to the presence of parallel transversal wrinkles throughout the labial and lingual surfaces of the crown. A fourth specimen is considered as belonging to a neosuchian tooth, because it has a circular cross-section, lack of labiolingual compression, and a serrated carina. Although represented by isolated shed teeth, these findings allow increasing the knowledge of the Cretaceous fauna of the Bajo de la Carpa Formation.