The asteroid genus Haccourtaster (Echinodermata, Goniasteridae) in the Bohemian Cretaceous Basin, Czech Republic

Numerous dissociated ossicles of a small goniasterid asteroid collected from nearshore sediments of Early–early Middle Turonian age in the Bohemian Cretaceous Basin are referred to a new taxon, Haccourtaster hrbac sp. nov. This is only the second known member of the genus, the type species of which (H. aemstelensis Jagt) comes from the Upper Campanian of Belgium. The new, slightly more primitive species markedly extends downwards the range of the genus, whose main feature (i.e., the system of cavities in the marginal frame, joining the main body cavity), is discussed. Data on ontogenetic changes as well as on the composition of ossicle assemblages are presented and palaeoecological aspects briefly discussed.