A phylogenetic interpretation of hamacanthids (Demospongiae, Porifera), with the redescription of Hamacantha popana



The study of the phylogenetic relationships of Hamacantha Gray. 1867 showed it to be more closely related to mycalids than to desmacellids, on the basis of its highly cavernous choanosome with stout ascending tracts of megascleres, easily detachable ectosome with a reticulation of megasclere bundles, and presence of rosettes and of true toxa. Since Pozziella Topsent, 1896 is recognized as a good genus, close to Hamacantha. the family name Hamacanthidae Gray, 1872 may be retained for this assemblage. This family is the sister-group of the Mycalidae Lundbeck, 1905 branch, and they both have Desmacellidae Ridley & Dondy, 1886 as sister-group. A cladogram expressing these relationships is provided and compared with previous ones in the literature. Mycalidae, Hamacanthidae, Desmacellidae, Cladorhizidae and ‘guitarrids’ form a monophyletic group by sharing two derived characters: faintly-necked styles, and sigmancistra derivatives.