The discovery of a new species of Spilodiscus Lewis in Florida prompted a reanalysis of phylogenetic relationships among the known species. Spilodiscus skelleyi new species is unusual among species of Spilodiscus in its black elytra, small size, and dentate mandibles. While S. skelleyi shares the last two of these features with the Gulf coastal S. flohri Lewis, differences in aedeagal structure and external setation argue against a close relationship between these two species. Many characters that have been considered phylogenetically informative in this group possibly are quite plastic in the course of evolution.