Mattaspongia, Rigby, 1970

Genus MATTASPONGIA Rigby, 1970

Remarks. Rigby (1970) erected the genus Mattaspongia and the family Mattaspongiidae because there were no comparable genera within what he considered to be the closest family, the Dictyospongiidae Hall and Clarke, 1899 . The visible characters of Mattaspongia did not fit well with the definition of the Dictyospongiidae , as the genus lacks a woven meshwork and the spicules are effectively loose within soft tissues (the lyssacine condition). However, Finks and Rigby (2004b) refined the definition of the Dictyospongiidae to include six subfamilies, with the genus Mattaspongia included in the Subfamily Thysanodictyinae, Hall and Clarke, 1899 , which involves “Dictyospongids with coarse ridgelike, quadrate mesh that may represent radially erect lamellae, spicule bundles, coarse pentactins or a combination thereof” ( Finks and Rigby, 2004b: 398). This still does not reasonably accommodate Mattaspongia , as it possesses a quadrate mesh but this reticulation lacked any coarse, ridge-like development, or even overlapping spicule rays. However, it is distinct from earlier reticulosans in being dominated by a single size of hexactin, rather than having subdivided quadrules. We therefore follow Rigby’s (1970) original interpretation, including Mattaspongia tentatively within its own family, and rejecting an assignment to the dictyosponges.