They were shaped like stocky lizards, with broad-cheeked skulls. Their cheeks sported a stout backward-pointing spike. Hypsognathus, from North America, had many cheek spikes. Procolophon, the genus after which the group was named, is unusual. Their skulls resemble the turtles', sharing a posttemporal fenestra. Accordingly, they have historically been classed alongside the turtles under the Anapsida.
Up to the early Triassic, their teeth were sharp, indicating an insectivorous diet. Later in the Triassic their teeth became broader, indicating a switch to a herbivorous diet. They became extinct at the end of the Triassic.
Recent findings indicate that these animals may have been found in Antarctica in the Early Triassic, thereby the earliest evidence of tetrapods in the Antarctic.
^Cisneros, J. C. (2008). "Phylogenetic relationships of procolophonid parareptiles with remarks on their geological record". Journal of Systematic Palaeontology6 (3): 345–366. doi:10.1017/S1477201907002350.
^Hans-Dieter Sues and Robert R. Reisz (2008). "Anatomy and Phylogenetic Relationships of Sclerosaurus armatus (Amniota: Parareptilia) from the Buntsandstein (Triassic) of Europe". Journal of Vertebrate Paleontology28 (4): 1031–1042. doi:10.1671/0272-4634-28.4.1031.
^Ruta, M.; Cisneros, J. C.; Liebrecht, T.; Tsuji, L. A.; Müller, J. (2011). "Amniotes through major biological crises: Faunal turnover among Parareptiles and the end-Permian mass extinction". Palaeontology54 (5): 1117–1137. doi:10.1111/j.1475-4983.2011.01051.x.