Pareiasauria: More on Morphology

Pareiasaur skulls were covered with characteristic sculpturing pattern consisting of bumps, pits, and processes. The numerous specializations of pareiasaur skulls make them easy to recognize. These include (pictured below for easy reference):

Pareiasaur skulls in lateral (A, B) and dorsal (C, D) views. A, C, Bradysaurus baini. B, D, Elginia mirabilis. Abbreviations: B. su., boss of the supratemporal; P. e. sq., posterior extension of the squamosal; V. fl. qj., ventral flange of the quadratojugal. Reproduced with permission from Lee (in press).

It has been suggested that pareiasaurs are the closest known relatives of turtles. This theory is based on several synapomorphies, including the following:

Pareiasaur skulls in palatal (roof of the mouth) view. A, Deltavjatia vjatkensis. B, Scutosaurus karspinski. Abbreviations: Ch, choana; So. f., suborbital foramen. Reproduced with permission from Lee (in press).

Continue exploring the wonderful Anapsida!


Laurin M. and R. R. Reisz. 1995. A reevaluation of early amniote phylogeny. Zoological Journal of the Linnean Society 113: 165-223.

Lee, M. S. Y. 1993. The origin of the turtle body plan: bridging a famous morphological gap. Science 261: 1716-1720.

Lee, M. S. Y. In press. A taxonomic revision of pareiasaurian reptiles: implications for Permian terrestrial paleoecology. Modern Geology: 66 pages, 17 figures.