Genus RHOMBOCLADIA Rogers, 1900

Type species. Rhombocladia delicata Rogers, 1900, by original designation. Pennsylvanian (Upper Coal Measures) ; Kansas, USA .

Diagnosis. Ramose colonies. Flattened branches bearing 4–12 zooecial rows. Vestibule weakly developed. Diaphragms rare. Superior hemisepta usually developed. Oval apertures arranged in a diagonal pattern. Autozooecial chambers rhombic in mid-tangential section. Macroacanthostyles often occurring at distal ends of autozooecial apertures. Microacanthostyles present in zooecial walls, sometimes forming star-like accumulations. Leptozooecia rarely present on the frontal surface or on lateral parts of branches. Dorsal wall very thin.

Remarks. The genus Rhombocladia differs from Chainodictyon Foerste, 1887, by having a ramose instead of a reticulate colony form and by the development of hemisepta. From Kallodictyon Morozova, 1981, it differs in colony-form, the thin dorsal wall and the absence of leptozooecia on the dorsal surface of the colony.

Occurrence. Middle Devonian – Upper Permian; worldwide.