Named By: H. H. Lane - 1945.
Classification: Chordata, Reptilia, Diapsida, Araeoscelida, Petrolacosauridae.
Species: P. kansensis.
Size: 40 centimetres long.
Known locations: USA, Kansas.
Time period: Gzhelian of the Carboniferous.
Fossil representation: Well enough preserved to reveal the full morphology.
is the first diapsid known in the fossil record. The teeth are small
and sharp suggesting insectivorous feeding, like the vast majority of
the other small reptiles of the time. Also like many of the early
diapsids, it was superficially similar to today’s small lizards.
Petrolacosaurus is very similar to another reptile called Araeoscelis that lived in the early Permian, although the latter has more robust dentition.