Bonitasaura salgadoi: A beaked sauropod in the Late Cretaceous of Gondwana

SEBASTIÁN APESTEGUÍA

NATURWISSENSCHAFTEN

Springer-Verlag

Lugar: Berlin / Heidelberg; Año: 2004 p. 493 - 497

0028-1042

Ornithischian and theropod dinosaurs were morphologically diverse during the Cretaceous. In contrast, sauropods generally have been considered relatively conservative. The anatomy of Bonitasaura salgadoi, a new 9 m titanosaurian sauropod from Upper Cretaceous beds of Patagonia, suggests that this traditional interpretation may be erroneous. Its unusual, rectangular lower jaw possesses narrow, anteriorly restricted teeth and shows evidence of a sharp keratinous sheath over the non-dentigerous region that probably had a maxillary counterpart and worked to guillotine plant material. This discovery definitely demonstrates that titanosaurs acquired a mandibular configuration similar to that of some basal diplodocoids, as had already been suggested by the lower jaw of the controversial genus Antarctosaurus. This oral configuration, plus the beak-like structure, renders these sauropods partially comparable to the highly diverse Laurasian ornithischian dinosaurs, which remain poorly represented in Gondwanan landmasses.