Taxonomic and geographic novelties of Acarnus (Porifera: Demospongiae) from the Brazilian coast, with description of two new species.

Acarnus are poecilosclerid sponges characterized mainly by cladotylote megascleres. Five species are known on the Brazilian coast: Acarnus innominatus Gray 1867, Acarnus radovani (Boury-Esnault, 1973), Acarnus toxeata Boury-Esnault, 1973, Acarnus nicoleae van Soest, Hooper & Hiemstra, 1991 and Acarnus microxeatus Nascimento & Pinheiro, 2023. This study describes two new Brazilian species, Acarnus hooperi sp.

Exploring depth-related patterns of sponge diversity and abundance in marginal reefs.

Marine sponges play a vital role in the reef's benthic community; however, understanding how their diversity and abundance vary with depth is a major challenge, especially on marginal reefs in areas deeper than 30 m. To help bridge this gap, we used underwater videos at 24 locations between 2- and 62-meter depths on a marginal reef system in the Southwestern Atlantic to investigate the effect of depth on the sponge metacommunity. Specifically, we quantified the abundance, density, and taxonomic composition of sponge communities, and decomposed their gamma () diversity into alpha () and beta () components.

New records of Neopetrosia carbonaria (Lamarck, 1814) from the Brazilian coast reveal new morphological features and spicule types.

Sponges of the family Petrosiidae have usually a stony and brittle texture due the high silica content of the mineral skeleton that is formed by a more-or-less regular isotropic reticulation of undefined primary and secondary tracts. Neopetrosia species are distributed worldwide and twelve species are found in the Tropical Western Atlantic Ocean, of which four are recorded from the Brazilian coast. Here, we describe new Neopetrosia carbonaria specimens from several localities along the NE Brazilian coast, analyze the Neopetrosia carbonaria holotype and review the previous record of N.

Two new Clathria (Axosuberites) Topsent, 1893 (Demospongiae: Poecilosclerida) from Northeastern Brazil.

The genus Clathria Schmidt, 1862 is the richest genus of the family Microcionidae, but only 20 species have been recorded from Brazil until now. Clathria (Axosuberites) Topsent, 1893 is characterized by having digitate, whip-like, arborescent and flabellate growth forms, lacking echinating spicules, well differentiated axial and extra-axial skeleton, styles and/or subtylostyles as principal spicules, and microscleres palmate isochelae and toxas. The subgenus contains 19 valid species, with worldwide distribution predominantly in shallow waters.

A new species of Characella Sollas, 1886 (Tetractinellida; Demospongiae; Porifera) from deeper waters off the coast of Brazil.

Sponges of the Family Pachastrellidae Carter, 1875 are distributed worldwide and found generally in deep water. Up to date, only four species are known for the Brazilian coast (Muricy 2018): Characella aspera Sollas, 1886, C. capitolii Mothes et al.

Description of three species of Eurypon Gray, 1867 (Raspailiidae: Demospongiae: Porifera) from the Western Atlantic and a name to replace the the secondary homonym Eurypon topsenti.

Eurypon  Gray, 1867 comprises 49 valid species distributed worldwide, and in an extensive bathymetric range. Three Eurypon species are known for Brazil, all endemic from the Northeast region. Here, we describe three new species of Eurypon.

Halichondriidae Gray, 1867 from the Northeastern Brazil with description of a new species.

In this paper we report and describe material of Halichondriidae sampled at 11 different stations in the Brazilian northeastern coast. Halichondria (Halichondria) marianae sp. nov.

A new shallow water species of Artemisina Vosmaer, 1885 (Microcionidae, Demospongiae; Porifera) from Northeastern Brazil.

Artemisina is a microcionid characterized by lacking a distinctive choanosomal skeleton or definite spongin fibres, lacking also echinating spicules, and with a nearly radial ectosomal skeleton (Hooper 2002). The genus currently has 19 valid species, six of which are recorded from the Atlantic Ocean (Van Soest et al. 2016): A.

New Genus and species of Heteroxyidae from Brazil (Axinellida: Demospongiae: Porifera), with a revised identification key for the family.

Alveospongia sinuosclera gen. nov. sp.

Neopetrosia de Laubenfels, 1949 from Brazil: description of a new species and a review of records (Haplosclerida: Demospongiae: Porifera).

The genus Neopetrosia was characterized by has fine brushes of oxeas issued from subectosomal tracts and compact choanosomal network. We report and describe here specimens collected in the coast of Brazil: Neopetrosia sulcata sp. nov.

Desmacella Schmidt, 1870 from Brazil: Description of two new species and a review of records (Desmacellida: Demospongiae: Porifera).

Three species of Desmacella Schmidt, 1870 are described from the Brazilian coast: Desmacella microsigmata sp. nov., Desmacella tylovariabilis sp.

A new species of Lissodendoryx (Anomodoryx) Burton, 1934 (Porifera: Demospongiae: Poecilosclerida) from deeper waters off the Atlantic coast of Brazil.

The members of Lissodendoryx Topsent, 1892a are recognized by a spicule combination of ectosomal tylotes or strongyles, isodictyal reticulate architecture, arcuate isochelae and sigmas (Hofman & Van Soest 1995; Van Soest 2002). Five subgenera of Lissodendoryx, are recognized (Van Soest 2002): Lissodendoryx (Acanthodoryx) Lévi, 1961, L. (Anomodoryx) Burton, 1934, L.

Two new cleistocheliferous species of Clathria of sciophilous habitats from Northeastern Brazil (Poecilosclerida: Demospongiae: Porifera).

We describe two new species of Clathria (Microciona) Bowerbank, 1862: C. (M.) crassitoxa sp.

Three new species of Eurypon Gray, 1867 from Northeastern Brazil (Poecilosclerida; Demospongiae; Porifera).

Three new species of Eurypon from Northeastern Brazil are described: Eurypon clavilectuarium sp. nov.; Eurypon suassunai sp.

Two new species of Aulospongus Norman, 1878 with a key to the Atlantic species (Poecilosclerida; Demospongiae; Porifera).

We describe two new species: Aulospongus trirhabdostylus sp. nov. and Aulospongus mandela sp.

Two new species of the family Niphatidae van Soest, 1980 from Northeastern Brazil (Haplosclerida: Demospongiae: Porifera).

This paper deals with niphatid sponges from the coast of the Bahia State, northeastern coast of the Brazilian shelf (southwestern Atlantic). Two new species are described, Amphimedon estelae sp. nov.

Clathria (Clathria) Schmidt, 1862 from Brazil with description of a new species and a review of records (Poecilosclerida: Demospongiae: Porifera).

We report and describe material of Clathria (Clathria) (Poecilosclerida: Microcionina: Microcionidae) collected from the coast of Brazil: Clathria (C.) nicoleae sp. nov.