A new Entomolepididae genus and a new species of Spongiopsyllus Johnsson, 2000 (Copepoda, Siphonostomatoida) and their association with Aplysina Nardo, 1834 (Porifera, Demospongiae) in Todos-os-Santos Bay, Bahia, Brazil.

The Entomolepididae family is a small taxon with a very characteristic body morphology and is represented, in the Atlantic Ocean, by three genera and five species. A recent study in Todos-os-Santos Bay, in Bahia State, has revealed a new species of Spongiopsyllus and a new species and genus belonging to the Entomolepididae. The new species of Spongiopsyllus is found in association with the sponge Aplysina cauliformis (Carter, 1882) sampled at the Porto da Barra beach. It is distinguished from its congeners mainly by differences in the segmentation pattern of the antennule, endopod of antenna, and the setation of the maxillule, maxilla and maxilliped. The new genus and species from Parmulodinae Eiselt, 1959 is found in association with the sponge Aplysina solangeae Pinheiro, Hajdu Custódio, 2007, sampled at the Yacht Club Beach. The genus differs from others Parmulodinae mainly due to segmentation pattern of the antennule, endopod of antenna, maxilliped and swimming legs.

On the Tethyida (Porifera, Demospongiae) from Bahia State, northeast Brazil, with descriptions of two new species, taxonomic appointments and new records.

The recently proposed order Tethyida is characterized by the presence of megasclere styles, tylostyles or oxeas arranged in tracts ending as bouquets at or near the surface, and microsclere euasters. Two new species are described from the shallow coastal reefs (0-10 m) of Bahia, Brazil. Timea kamasary sp. nov. is represented by thin sciaphylous specimens with three categories of spicules: tylostyles, spined spheroxyasters and spined/smooth oxyasters in varied sizes. This species differs from Timea unistellata (Topsent, 1892) by having a different category of oxyasters. Tethya bitylastra sp. nov. is characterized by having strongyloxeas I and II, spherasters, oxyasters I and II, strongylasters and two categories of tylasters. This new species differs from Tethya maza Selenka, 1879 by having a second category of tylaster. Furthermore, we present taxonomic appointment for Timea berlincki (Leite, Fonseca, Leal Hajdu, 2015) and Tethya maza and the first record of Timea stenosclera (Hechtel, 1969) for the Southwest Atlantic.