A taxonomic revision of small dicynodonts with postcanine teeth

The validity of 18 genera of small (skull length less than 150 mm) dicynodonts with postcanine teeth has been assessed. It is concluded that only four genera, Emydops, Eodicynodon, Robertia and Pristerodon, can be defined satisfactorily on the basis of well-preserved and adequately prepared specimens. Of the remaining 14 genera, ten are not valid and may be accommodated within the four well-characterized genera. Three additional genera (Chelyoposaurus, Koupia and Taognathus) should become nomina nuda since they are based on inadequately diagnosed material which in the case of the first two genera is now lost. Brachyprosopus, although based on a single somewhat inadequate specimen, is also considered valid although future examination of the type (not seen by us) may require reassessment of this opinion. We discuss briefly the nature of the taxonomic characters used, and the stratigraphic distribution of the four major genera.