new mid-jurassic sauropod: Archaeodontosaurus

[Jose Ignacio =?unknown?q?Ruiz-Ome=F1aca?= <jigruiz@unizar.es>]

ERIC BUFFETAUT. 2005. A new sauropod dinosaur with prosauropod-like teeth from 
the Middle Jurassic of Madagascar. Bulletin de la Société Géologique de France, 
176(5), 467-473

Key words. - Dinosauria, Sauropoda, Middle Jurassic, Madagascar.

Abstract. - A dentary bone containing several teeth, from the Middle Jurassic 
(Bathonian) of northwestern Madagascar is described as the type of a new 
sauropod dinosaur taxon, Archaeodontosaurus descouensi, n.g., n.sp. This taxon 
is characterised by the unusual combination of a dentary with a deep anterior 
part, as in advanced sauropods, and teeth with large serrations and a convex 
lingual side, which resemble the teeth of prosauropods. A more common pattern 
in early sauropods is the combination of a low, prosauropod-like dentary and 
spoon-shaped, sauropod-like teeth. Although the condition in Archaeodontosaurus 
descouensi strongly suggests that basal sauropods had prosauropod-like teeth, 
what is known of the jaw and dentition in various early and middle Jurassic 
sauropods indicates mosaic evolution along different paths during the early 
diversification of the group. Archaeodontosaurus descouensi differs from 
Jurassic sauropod material from Madagascar, previously described a!
 s Bothriospondylus and Lapparentosaurus, which needs revision. It appears that 
at least two distinct sauropods, with different tooth morphologies, are present 
in the Middle Jurassic of Madagascar.