Xestospongia de Laubenfels, 1932

Rocha, Lívia, Moraes, Fernando, Salani, Sula & Hajdu, Eduardo, 2021, Taxonomy of Petrosiidae Van Soest, 1980 (Haplosclerida, Porifera) from Brazil, Zootaxa 5004 (2), pp. 251-287 : 274

Genus Xestospongia de Laubenfels, 1932

Petrosiidae with an ectosomal skeleton consisting of only a tangential disorganised network of single spicules or spicule tracts, which originates from the terminal ends of choanosomal tracts. Choanosomal skeleton a dense network forming roundish to polygonal large-spaced meshes delimited by unordered spicules. Free spicules rare, but brushes formed by the ends of connecting spicules are visible on the internal part of the mesh walls. Megascleres, usually oxeas or strongyles, variable in size (mostly reaching over 300 µm), but not assignable to more than one class (adapted from Desqueyroux-Faúndez & Valentine 2002).

Remarks. The distinction of Xestospongia from Neopetrosia can be subtle, especially when dealing with species bearing relatively small spicules (200–300 µm). As pointed out above under the remarks to the diagnosis of Neopetrosia , that genus tends to show neater roundish meshes, both in the ectosome and choanosome skeletons. Consequently, we merged here the diagnosis proposed by Desqueyroux-Faúndez & Valentine (2002) with their own remarks offered (Systema Porifera, p. 910), when comparing Neopetrosia and Xestospongia .