Serpianosaurus is an extinct genus of pachypleurosaur. Fossils have been found from the middle Grenzbitumenzone, the oldest strata of Monte San Giorgio, Switzerland, an area well known for its abundant pachypleurosaur remains. The locality dates back to sometime around the Anisian/Ladinian boundary of the Middle Triassic, around 237 Ma, with Serpianosaurus most likely occurring strictly during the earliest Ladinian. This makes it the oldest sauropterygian from Monte San Giorgio known to date. Certain aspects of its morphology also suggest it is one of the most basal forms. The genus can be distinguished from other closely related pachypleurosaurs on the basis of its proportionally large skull and straight jaw. Like many other pachypleurosaurs, sexual dimorphism can be seen in Serpianosaurus. Males and females are thought to differ in humeral size and shape. Any pachyostosis of the ribs is absent in Serpianosaurus specimens. It is closely related to the genus Neusticosaurus.
Serpianosaurus mirigolensis on display at Zurich natural history museum.
^Sander, P. M. (1989). The Pachypleurosaurids (Reptilia: Nothosauria) from the Middle Triassic of Monte San Giorgio (Switzerland) with the Description of a New Species. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences325(1230):561-666.
^Rieppel, C. (1994). The status of Anarosaurus multidentatus von Huen (Reptilia, Sauropterygia), from the Lower Anisian of the Lechtaler Alps (Arlberg, Austria). Paläontologische Zeitschrift69(1-2):289-299.
^Rieppel, O. (1989). A New Pachypleurosaur (Reptilia: Sauropterygia) from the Middle Triassic of Monte San Giorgio, Switzerland. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences323(1212):1-73.