Langobardisaurus? rossii (Bizzarini, Muscio and Rossi 1995, MFSN 19235, nicknamed "Renestosaurus" here) is a small basal lepidosaur that has confounded workers who first thought the area of the skull contained a long curled up neck, like that of Langobardisaurus. Renesto and Dalla Vecchia (2007) cleared that up for us, noting the ossified pisiform and possible presence of a shearing blade replacing lateral teeth on both jaws, they tentatively placed the specimen with sphenodontian rhynchocephalians, but more certainly within the old Lepidosauromorpha. They did a good job with few clues.
In the large reptile tree, L. rossii was derived from a sister to Homoeosaurus. A sister to Renestosaurus gave rise to tiny Scandensia, the last known common ancestor of the Squamata. So this is a key taxon in the systematics of lizards. Lizards evolved when the smaller descendants of "Renestosaurus" rossii became miniaturized.
Distinct from Homoeosaurus, the mandible of "Renestosaurus" was deeper and convex ventrally. One cannot be sure if the vertebral column was humped or just preserved that way, but if so, the hump was less pronounced due to anterior rib length. The entire vertebral column of Renestosaurus was more gracile with shorter chevrons. The pectoral girdle was unfused and the cleithrum disappeared. The forelimbs were relatively larger. The pelvis was more gracile and the hind limbs were more gracile with a smaller foot. L. rossii is distinquished by a metacarpal 3 longer than the others and a longer digit 3. |
