First occurrence of the genus Sphenothallus Hall, 1847 (Cnidaria) in the Carboniferous of the Dnipro-Donets Depression, Ukraine

The first occurrence of the problematic cnidarians Sphenothallus Hall (S. sp. 1 and S. sp. 2) is described from upper Viséan and ?Bashkirian (Carboniferous) black shales of the Dnipro-Donets Depression in NE Ukraine. Carboniferous Sphenothallus spp. from the Dnipro-Donets Depression apparently led an epifaunal gregarious lifestyle, preferring paleobasin areas with slow sedimentation rates, low current energy, and dysaerobic environments, as already suggested by literature data. The discovery of representatives of the genus Sphenothallus in Carboniferous strata of Ukraine significantly extends our knowledge about the geographic distribution of these animals. Further, it confirms their preference for environments with slow sedimentation. Keywords: cnidarians, Sphenothallus, Carboniferous, Dnipro-Donets Depression, Ukraine.