European Russia has been the source of many procolophonoid taxa from both the Permian and Triassic, and a Permian origin for the procolophonoid family Procolophonidae has been based on the Russian taxon Microphon exiguus. Recently, this taxon was reclassified as a seymouriamorph and, in its place, the taxa Nyctiphruretus, Suchonosaurus, and Kinelia from the Middle and Upper Permian of Russia were suggested as “procolophons”, using evolutionary−systematic classification methods. In recent phylogenies, however, Nyctiphruretus has been recovered as a non–procolophonoid parareptile, whereas Kinelia and Suchonosaurus have never been included in a phylogenetic study. Re−examination indicates that Suchonosaurus is a member of the procolophonoid subfamily Procolophonidae based on the shape of the maxillary bone and the external naris, the laterally visible maxillary depression, and the number and type of maxillary teeth. Kinelia, on the other hand, is excluded from the Procolophonoidea because of its subpleurodont dental attachment and lack of any procolophonoid features. Thus, Suchonosaurus is the only confirmed Permian procolophonid from the Permian of Russia. Additionally, re−examination of the holotype of Microphon exiguus confirms that it is identical to the seymouriamorph specimens recently included in the genus Microphon and that it lacks procolophonoid features. The earliest unequivocal record of the subfamily Procolophonidae is confirmed from the Late Permian of Russia, making Russia the only region where, with certainty, both Permian and Triassic procolophonids have been discovered.

Key words: Parareptilia, Procolophonoidea, Procolophonidae, origin, palaeobiogeography, Permian, Russia.

Laura K. SäiIä [Laura.Saila@helsinki.fi], Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queen’s Road, Bristol, BS8 1JU, United Kingdom; Jernvall Evo-Devo Research Group, Institute of Biotechnology, Viikinkaari 9 (PL 56), 00014 University of Helsinki, Finland (current affiliation).