Anuran maxillary, squamosal, and ilial elements from the Late Eocene of Hampshire and the Isle of Wight in southern coastal England represent a new species, Thaumastosaurus wardi, of this previously monotypic genus. Teeth, represented for the first time in the fossil record of this genus, are of the pedicellate type but appear to have specialized swollen tooth crowns. Based on the unique pit and ridge sculpturing of the cranial bones, the pedicellate teeth, and ilial characters of Thaumastosaurus, the genus resembles the leptodactylid genus Caudiverbera (Telmatobiinae) of the modern fauna of Chile and the Miocene of Argentina. It is suggested, however, that Thaumastosaurus should be considered of uncertain familial relationships (familia incertae sedis) until adequate material becomes available.