Rotaryus gothae, a new genus and species of trematopid temnospondyl amphibian, is described on the basis of a single specimen from the Lower Permian (Wolfcampian) Tambach Formation, lowermost formational unit of the Upper Rotliegend Group or Series of the Bromacker locality in the midregion of the Thuringian Forest, central Germany. This is only the second trematopid species to be reported from not only the Bromacker locality, but also outside of North America. The holotype includes the greater portions of the skull with attached mandibles and closely associated partial postcranium. A combination of autapomorphic and synapomorphic characters clearly distinguishes Rotaryus from all other well-known members of Trematopidae. A cladistic analysis of Dissorophoidea was performed that included well-known members of Amphibamidae, Dissorophidae, and Trematopidae. This included Ecolsonia Vaughn, 1969, whose assignment to either Trematopidae or Dissorophidae remains controversial. The resultant cladogram depicts three lineages: 1) Amphibamidae as monophyletic and the sister clade to the unresolved trichotomy of a trematopid clade comprising Anconastes Berman et al., 1987, Tambachia Sumida et al., 1998, Fedexia Berman et al., 2010, Phonerpeton Dilkes, 1990, Acheloma Cope, 1882, and Rotaryus, a dissorophid clade comprising Dissorophus Cope, 1895, Broiliellus Williston, 1914, Aspidosaurus Broili, 1904, Cacops Williston, 1910, and the monogeneric clade Ecolsonia; 2) Rotaryus is nested within the Trematopidae clade as the sister taxon to the terminal dichotomy of Acheloma and Phonerpeton, which in turn forms the sister clade to that comprising Fedexia as the sister taxon to the terminal dichotomy of Tambachia and Anconastes; 3) the dissorophid clade as forming an unresolved, trichotomy comprising Dissorophus, Broiliellus, and the terminal dichotomy of Aspidosaurus and Cacops. The pattern of relationships of the trematopid clade suggests a basal, subfamily division.