Cyclacanthia n.g. (Demospongiae: Poecilosclerida: Latrunculiidae incertea sedis), a new genus of marine sponges from South African waters, and description of two new species

Abstract

The new genus Cyclacanthia n.g. is erected in the poecilosclerid Family Latrunculiidae for the type species Latrunculia bellae Samaai & Kelly, 2003, and two further species, Cyclacanthia cloverlyae sp. nov., and Cyclacanthia mzimayiensis sp. nov.. The latter species are from the subtropical east coast of South Africa, whereas C. bellae has only been found further south in warm temperate Algoa Bay. Cyclacanthia n.g. differs from other Latrunculiidae genera in the ontogeny, morphology and structure of the mature microsclere, the isospinodiscorhabd, which has only three major whorls of projections as opposed to the four in species of Latrunculia du Bocage. Additional diagnostic characters include the presence of broad swathes of megascleres that diverge from the base of the sponge towards the upper choanosome, where they form loose brushes and the typical whispy reticulation of most Latrunculiidae. The ectosome is composed of a dense tangential layer of megascleres, an irregular palisade of microscleres at the surface, and a permanently encrusting habit. Cyclacanthia n.g. is the second new latrunculid genus recently described from shallow subtidal South African waters, following major revision of the family. The presence of species in four of the five known genera in the family, on South African coastlines, suggests a diversity hot-spot for the family in this region.