<E1>Pleionastraea</E1>gen. nov. of the family Lithostrotionidae is described from the Lower Carboniferous Brigantian Stage of northern England. Two species,<E1>P. magna</E1><E1>P. matura</E1>, are referred to it. This astraeoid/thamnasterioid genus is distinguished from<E1>Orionastraea</E1>by its larger dimensions, but is considered to have followed the same evolutionary trend of a gradual breakdown of the corallite wall.