Genus CAVERNELLA Morozova, 1974

Type species. Fenestella dvinensis Schulga-Nesterenko, 1951 = junior subjective synonym of Fenestella praecavifera Schulga-Nesterenko, 1951, subsequently designated by Morozova (1974). Pennsylvanian (Upper Carboniferous, Kasimovian); Russia.

Diagnosis. Colony fan-shaped or conical. Branches straight, connected by thin dissepiments. Two rows of autozooecia on branches, overlapped basally. Autozooecial chambers pentagonal to triangular in mid-tangential section. Axial wall between autozooecial rows strongly undulating. Superior hemisepta absent or poorly developed; inferior hemisepta absent. Low keel with a single row of nodes on the observed surface. Pairs of heterozooecia (cavernozooecia) on the reverse side of branches or on dissepiments, opening into the fenestrule (modified after Morozova 2001, p. 46).

Occurrence. Pennsylvanian (Upper Carboniferous) – Upper Permian; Eurasia, North America.

Remarks. Cavernella Morozova, 1974, differs from other fenestrates in the presence of cavernozooecia.