Acarnus


Acarnus is a genus of sponges belonging to the family Acarnidae. The genus has almost cosmopolitan distribution.

Description

Species are non-fistulose sponges with encrusting to massive growth forms. They have ectosomal tylotes with microspined ends. These form tangential or paratangential tracts. The choanosomal skeleton is isodictyal, isotropic, or anisotropic. In encrusting species, it may occasionally be plumose or hymedesmioid. The skeletal tracts are covered with smooth styles, which may be spined by cladotylotes. Cladotylotes are unique to this genus. They are monoaxon megascleres with at least one hooked end. The other end may also have hooks, or it may be a pronounced smooth knob. The microscleres are palmate isochelae and several forms of toxas.

Species

The following species are recognised: