Pleurosaurus goldfussi (Meyer 1831, Late Jurassic. 60 cm in length). It was long thought that the rhynchocephalians produced a marine lineage known as the pleurosaurs, named for the genus, Pleurosaurus. Now the large reptile tree nests Pleurosaurus as derived from Megachirella and Palaegama, outside of the traditional Rhynchocephalia and not directly related to Palaeopleurosaurus, yet at the base of a slightly extended Rhynchocephalia. The long low skull of Pleurosaurus aligns it with Megachirella and Marmoretta a derived, probably terrestrial taxon.
Distinct from Megachirella, the skull of Pleurosaurus has a shorter naris. The upper temporal fenestrae are smaller. The teeth are large triangles shaped like saw teeth. The fused parietal is narrower.
Distinct from the post-crania of Palaegama, the vertebrae of Pleurosaurus are more numerous creating a longer torso with much shorter limbs. |
