Family Hemiasterellidae Lendenfeld, 1889

Abstract

Hemiasterellidae Lendenfeld (Demospongiae, Hadromerida) contains 11 nominal genera, of which six are valid, and approximately 20 described species worldwide. Species live in all oceans, predominantly in shallow waters, are often dichotomously branching or flabel- late, with hispid surface or conules and stiff texture. The family has a unique combination of euasters mainly at the surface, and monax- onic megascleres (styles and/or oxeas) with distinctly structured arrangement of axial and extra-axial skeletons. Genera are differentiated predominantly on the basis of whether megascleres are diactinal or monactinal, development of the axial and extra-axial skeletons, presence or absence of ectosomal specialisation, and euaster morphology.