Order Aulocalycoida Tabachnick & Reiswig, 2000

Abstract

Aulocalycoida Tabachnick & Reiswig (Hexactinellida, Hexasterophora) contains two families and seven genera. The order is character- ized by a loose dictyonal framework built around a primary set of longitudinal strands constructed of extended dictyonal rays. Meshes are irregular. The families are differentiated by details of strand construction. Strands of Aulocalycidae contain single continuous axial fila- ments which are unlimited in length. Strands of Uncinateridae contain overlapping axial filaments contributed by a series of hexactins; individual constituent dictyonal rays are elongate but not unlimited in length. The poorly supported frameworks of distal growing margins are delicate and flexible, unlike those of the hexactinosidans and lychniscosidans which are rigid and brittle throughout.