Symplectella rowi (Porifera: Hexactinellida: Lyssacinosida) is a rossellid, not a euplectellid. J. Mar. Biol. Ass. U.K. in press

The monospecific hexactinellid sponge genus Symplectella endemic to New Zealand waters was originally assigned to family Rossellidae within the order Lyssacinosida (subclass Hexasterophora), although affinities to family Euplectellidae were also noted. Seventy-eight years later, the genus was transferred to Euplectellidae (subfamily Corbitellinae) on rather subjective grounds. Here, I test these two competing taxonomic hypotheses with molecular phylogenetic methods and demonstrate that Symplectella rowi is indeed a rossellid, as was originally suggested. The genus is officially transferred back to Rossellidae (subfamily Rossellinae), which represents another small step towards a more natural classification system of glass sponges.