Family Trachycladidae Hallmann

Abstract

Trachycladidae Hallmann (Demospongiae, Hadromerida), contains two genera with at least nine species, all having an axial (or basally) compressed skeleton, and an extra-axial plumo-reticulate skeleton, with megascleres predominantly oxeas, less often strongyles and/or (tylo-)styles, in spongin-enforced multispicular tracts, or in the case of encrusting species, megascleres erect on the substrate (in hymedesmioid arrangement). Ectosomal skeleton is a crust of spinispirae (spined vermiform spiraster-like spicules), with smooth microrhabds and/or spinispirae dispersed throughout the mesohyl. The two genera are differentiated on the basis of fundamental differ- ences in spinispirae morphology. Species are known from the shallow subtidal to about 220 m depth, distributed from temperate Australia, New Zealand and New Caledonia, Indonesia, East Africa and South Africa, Mediterranean and the western North Atlantic.