Family Aulocystidae Sollas, 1887

Abstract

Aulocystidae Sollas (Hexactinellida, Lychniscosida) consists of two genera, the well known Neoaulocystis (previously Aulocystis) with three species, and a new genus, Lychnocystis gen. nov., erected here to receive Cystispongia superstes Schmidt as type and only species. The genera are differentiated by both framework organization and spiculation. Neoaulocystis is constructed of thin-walled tubules which branch and anastomose. Lychnocystis is constructed of pillars and plates which branch and anastomose, but do not form tubules. Neoaulocystis has discohexasters and graphiocomes as microscleres while Lychnocystis has large onychexasters and discohexasters, but apparently lacks graphiocomes. A sturdy external siliceous crust may be formed as a terminal growth stage of some members of both gen- era. The family is restricted to tropical-temperate waters on western ocean basin margins: the West Indies, the Philippine-Indonesian region and the Red Sea, at depths of 82–1383m.