A New Species of Rhizodontiform Sarcopterygian Fish (Sarcopterygii: Rhizodontiformes) from the Lower Carboniferous of the Moscow Region

A new specimen of the genus Rhizodus—R. serpukhovensis represented by a fragment of the lower jaw, is described from the Lower Carboniferous (Serpukhovian Stage, Steshevian Regional Substage), of Central Russia (Moscow Region, Zaborie). Previously, this genus was only known from the Viséan of Western Europe and the USA. Good preservation of the new material allows the description of features unknown for this genus, such as the presence of an intercoronoid fossa and a branch of the mandibular seismosensory canal on the dentary. The morphological and functional analysis of the teeth of rhizodontids showed that R. serpukhovensis sp. nov. was the highest consumer in the trophic structure of the Steshevian vertebrate community, which is supported by the gigantic size and powerful jaws of this fish. Presumably, its diet consisted of large cartilaginous fishes and tetrapods.