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. is a massively encrusting sponge, with firm texture, soft, fleshy, but compact and compressible. Color in vivo is dark green, becoming grayish or brown after fixation in ethanol; the spicules are smooth oxeas. Amorphinopsis atlantica from the Northeastern Brazil is thickly encrusting to massively, also with firm texture, color in vivo is usually yellow to dark green and both distributed in different regions, brownish after fixation in ethanol; the spicules are smooth oxeas and styles. A taxonomic study of these samples is given, including description and illustrations.

The genus Oceanapia Norman, 1869 comprises 95 species worldwide, 20 from the Atlantic Ocean and seven from Brazil. Oceanapia includes sponges with hollow body and numerous fistulae; spicules are oxeas or strongyles and microscleres, if present, are sigmas or toxas. Specimens were collected by trawl at Rio Grande do Norte, Pernambuco and Pará States, Brazil. Two new species are described from the Northeast Region of Brazil: Oceanapia cordia sp. nov. and Oceanapia magna sp. nov. For two preoccupied combinations, new names are proposed, Oceanapia hechteli nom. nov. and Oceanapia topsenti nom. nov. Oceanapia stalagmitica (Wiedenmayer, 1977) is recorded and described for the first time from Brazil. A taxonomic study of seven specimens of Oceanapia from the North and Northeast region (Brazil) is given, including description, illustrations and geographical distribution. The two new species are compared with all other descriptions of Oceanapia from the Atlantic Ocean.

Desmacella is a Desmacellidae characterized by monactinal megascleres, arranged in plumose bundles; microscleres are sigmas and raphides; the latter may be absent (Hajud & Van Soest 2002). Thirty species are known worldwide, of which 19 occur in the Atlantic Ocean and three on the Brazilian coast: Desmacella annexa Schmidt, 1870; D. microsigmata, Cavalcanti, Santos & Pinheiro, 2015; D. tylovariabilis, Cavalcanti, Santos & Pinheiro, 2015 (de Voogd et al. 2022; Muricy 2022). In this paper, a new species of Desmacella from the Northeast region of Brazil is described. The material examined was compared with the descriptions and/or characterizations of all Desmacella species that occur in the Atlantic Ocean (Cavaltanti et al. 2015: 367–368). The specimen was preserved in ethanol 80% and is deposited in the Porifera Collection of the Natural History Museum of the Universidade Federal da Bahia.

Acanthella Schmidt, 1862 species are characterized by choanosomal skeleton of dendritic tracts cored by interwoven sinuously bent strongyles or strongyloxeas and echinated by straight styles, oxeas or anisoxeas (Van Soest et al. 2002). The genus Acanthella comprises 33 valid species, with six known from the Atlantic Ocean (Van Soest et al. 2018). Previously, the only record for Brazil was A. flagelliformis (Van Soest & Stentoft, 1988) (Muricy 2018). Species of the genus include a transition from shrub like ‘Axinellas’ and herbaceous species similar to the genus Suberites Nardo, 1833 (Schmidt 1862; Vosmaer 1912). Due to its heterogeneous complex of species, Acanthella has been confused with other axinellids. Similarities were seen in genera such as Phakellia (Van Soest et al. 2002), which shares spicule complement and comparable choanosomal skeletons. In the present study, we describe a new species of Acanthella from oceanographic expeditions of the northeast region of Brazil. Two specimens of Acanthella sp. nov. were collected by dredging at Ceará and Pernambuco State, Brazil. All specimens were preserved in 92% ethanol and deposited in the Porifera Collections at the Universidade Federal de Pernambuco (UFPEPOR). The taxonomic identification was carried out through analysis of spicules morphologies, using Light Microscopy (LM) and Scanning Electron Microscopy (SEM), following methods described by Hajdu et al. (2011).

A lectin from the marine sponge Haliclona (Reniera) implexiformis (HiL) was isolated by affinity chromatography on Sepharose™ matrix. HiL showed specificity for galactose and its derivatives. The glycoproteins porcine stomach mucin (PSM) and bovine stomach mucin (BSM) were potent inhibitors. Hemagglutinating activity of the lectin was maximal between pH 5.0 and 9.0. The lectin remained active until 60°C. The presence of CaCl 2 and EDTA did not affect the hemagglutinating activity. In SDS-PAGE, HiL showed a single band of 20 kDa under reduced conditions, whereas in the non-reducing conditions, it showed a band of 20 kDa and one additional band of 36 kDa. The average molecular mass determined by Electrospray Ionization Mass Spectrometry (ESI-MS) was 35.874 ± 2 Da in native and non-reducing conditions, whereas carboxyamidomethylatedlectin showed 18,111 Da. These data indicated that HiL consists in a dimer formed by identical subunits linked by disulfide bonds. Partial amino acid sequence of HiL was determined by mass spectrometry, and revealed that it is a new type of lectin, which showed no similarity with any protein. Secondary structure consisted of 6% α-helice, 31% β-sheet, 18% β-turn and 45% random coil. HiL showed significant reduction in the number of viable cells of Staphylococcus biofilms.