Occurrence of sterrasters of the Geodiidae (Demospongea, Choristida) in late Cenozoic strata of western Wellington Province, New Zealand

Abstract

Sterrasters, the microsclere siliceous spicules of certain marine sponges, have been recognized in strata ranging Irom Upper Miocene to Pleistocene in age, including some beds of the Pleistocene Hawera Series previously considered to be non-marine. The stcrrasters are described and compared with those of modern and fossil sponges from the New Zealand region. The genus Geodia Lamarck is definitely represented by the sterrasters examined, but the presence of other genera of the family Geodiidae cannot be ruled out, Attention is drawn to the usefulness of sterrasters as indicators of marine deposition, and it is suggested that these structures may be widespread in the Upper Cretaceous and Cenozoic “covering strata” of New Zealand.