The genus Simophis includes Brazilian and Paraguayan colubrid snakes with color patterns mimetic with triad-banded coral snakes of the genus Micrurus. Currently Simophis is thought to include two species: Simophis rhinostoma, described from Brazil and recorded in the literature from Paraguay, and Simophis rohdei, considered to be a Paraguayan endemic. The species are differentiated by the number of scale rows at midbody (15 in S. rhinostoma and 17 in S. rohdei) and the number of supralabial scales (7 in S. rhinostoma and 8 in S. rohdei). A review of specimens from Paraguay and Brazil indicate variation in the number of supralabial scales, and a reexamination of the holotype of Rhinaspis rohdei showed that it actually has 15 middorsal scale rows and not 17 as was indicated in the original description. A single specimen from Brasilia has 17 dorsal scale rows. The genus Simophis must be considered to be monotypic (S. rhinostoma), having 15 dorsal scale rows (rarely 17) and between 7 and 9 supralabials (rarely 5). The species has a unique combination of characters, some associated with arboreality (slender body, long tail, laterally keeled ventral scales), and one found in fossorial snakes (shovel-shaped rostral).