Subgenus Tsitsikamma Samaai & Kelly, 2002

Type species. Tsitsikamma favus Samaai and Kelly, 2002: 718; fig. 6A–G.

Diagnosis. Tsitsikamma species that are thickly encrusting to hemispherical attached to the substratum through a common base; have a rigid, thick honeycomb chamber like choanosome reinforced by very large, thick anisostyles. The isochiadiscorhabd microscleres are large, having a thick shaft and three sets of cylindrical-conical tubercles protruding from the shaft.

Remarks. We herewith establish the nominotypical subgenus Tsitsikamma subgen. nov. Samaai and Kelly, 2002, for the species T. favus, T. scurra, T. nguni Parker-Nance, 2019 and T. amatholensis sp. nov., based on the possession of dense megasclere tracts that form a rigid, honeycomb-like structure, with chambers visible to the unaided eye.