Three new intertidal sponges (Porifera: Demospongiae) from Brazil's fringing urban reefs (Maceio, Alagoas, Brazil), and support for Rhabderemia's exclusion from Poecilosclerida

The inventory of Brazil's marine sponge fauna is notably fragmentary; knowledge remains basic even in the vicinity of some important urban areas. Accordingly, we set up a plan to prioritize taxonomic study of sensitive areas, coupling high biodiversity potential and likely outstanding human pressure on biological resources. One such area comprises the fringing urban reefs of Maceio (Alagoas State, northeastern Brazil), from where three new demosponges are described here: Plakina coerulea sp. nov., Rhabderemia meirimensis sp. nov. and Mycale rubra sp. nov. The new Rhabderemia shares with Biemna, Desmacella, Neofibularia and Sigmaxinella, the possession of distally microspined sigmas. Recent molecular results have shown these taxa to be only distantly related to chelae-bearing Poecilosclerida, hence our decision to leave the new species as ordo incertae sedis. It is proposed that the intertidal or shallow subtidal sponge fauna in northeastern Brazil's reefs deserves enhanced conservation effort to preserve what remains in these highly impacted ecosystems.