Captorhinidae is a diverse group of small to medium-sized reptiles known from the Pennsylvanian and Permian. Some of its species evolved jaws with multiple rows of teeth that suggest a diet of high-fiber plant material. The authors describe in detail the known material of an early captorhinid with multiple tooth rows from the lower Permian (Cisuralian) of Oklahoma and north-central Texas. Because it differs from other known captorhinid species, it is placed in its own new genus, Sumidadectes.

‘Captorhinikos’ chozaensis Olson, 1954 is a captorhinid eureptile with multiple tooth rows from the lower Permian (Cisuralian: Kungurian) Clear Fork Group of north-central Texas and the Hennessey Formation of Oklahoma. It has five maxillary and four dentary tooth rows. We re-examined the available specimens referred to ‘Captorhinikos’ chozaensis to elucidate aspects of its skeletal structure and assess its phylogenetic relationships. Our parsimony analysis confirmed previous suggestions that this taxon is not referable to the same taxon as Captorhinikos valensis Olson, 1954 (type species of the genus) and ‘Captorhinikos’ parvus Olson, 1970 and thus is placed in its own new genus, Sumidadectes. It also recovered Sumidadectes chozaensis n. comb. as the earliest-diverging moradisaurine captorhinid.