Two new species of Haliclona (Chalinidae, Haplosclerida) are described here from Brazilian oceanic islands and the coast of Ceará State. They derive from collections undertaken between 1999 and 2014, and materials are deposited in the Porifera collection of Museu Nacional in Rio de Janeiro (MNRJ). Haliclona (Halichoclona) insularis sp. nov. can be distinguished from other Haliclona spp. in the western Atlantic by the combination of surface with light to deep red colour intermixed with white to beige areas (occasionally completely beige), white to beige choanosome, small fistular outgrowths, fragile consistency and blunt oxeas (90–175 × 1–5 μm) with irregular tips. Haliclona (Soestella) moraesi sp. nov. is the only western Atlantic species of Haliclona with the combination of thickly encrusting to cushion-shaped habit, purple or light pink colour, and a dense (sub)isotropic skeleton with rounded meshes, and without microscleres. Several attempts to amplify COI mtDNA and 28S C2–D2 rRNA for both species were unsuccessful, in spite of the initial successful extraction of genomic DNA. The number of Haliclona spp. known from the Brazilian coast is now 17. The long gap between species collection and formal description supports the concept of the taxonomic impediment, which is particularly marked in speciose taxa with little morphological disparity, as observed in Haplosclerida.

Bioeroding sponges of the Cliona viridis species complex play a large role in carbonate cycling and reef health. In the present study we provide the first record and a description of a Mediterranean lineage of C. viridis (Schmidt, 1862) in the south-western Atlantic. Specimens were collected in Maricás Archipelago, Rio de Janeiro State in September 2010 by scuba diving at 10–12 m depth and deposited in the Porifera collection of Museu Nacional, Universidade Federal do Rio de Janeiro. Morphologically, the specimens presently examined are very similar to those described in the beta and gamma growth form from the Mediterranean. The Brazilian and Mediterranean specimens share large and irregular papillae over 2 cm in diameter, megasclere tylostyles up to 500 µm long and microsclere spirasters with up to five twists and 34 µm long. A Maximum Likelihood analysis of 28S rDNA of C. viridis, C. aprica, C. jullieni, C. schmidti and C. varians was performed for a genetic identification of the Brazilian specimens. The Brazilian material is phylogenetically closer to the Mediterranean C. viridis than to the Caribbean and Indian Ocean members of this species complex included in the present analysis. Our results suggest that C. viridis is a cryptogenic species with a distribution extending from the Mediterranean to the eastern Atlantic and in the SE Brazilian coast or further.

Until now only two species of Cladorhiza have been reported from the SW Atlantic, namely C. diminuta and C. inversa, despite a total of 39 species reported from various parts of the globe. Here we describe a new species, C. nicoleae sp. nov., dredged from 750 m depth on the continental slope off SE Brazil during the French RV ‘Marion Dufresne’ expedition in 1987. It is an erect, pedunculated and club-shaped sponge, 26 mm high and with 12 radially arranged whip-like projections (each up to 3 mm long). The new species differs from its closest relative, C. inversa (redescribed here), by its possession of sigmas and sigmancistras. The holotype of Cladorhiza inversa is also a pedunculated sponge, 1.9 cm tall, with a cup-shaped body with an apical spur-like continuation of the stem and a crown of 16 projections (up to 8 mm long) radiating from the rim of the body.

Haliclona is an unusually species-rich genus in Porifera, with more than 400 species described. In spite of many subgenera used in the taxonomic housekeeping of these sponges, over half of them remain unassigned to a subgenus, thus encouraging a wide range of redescriptions and taxonomic revisions of materials from all around the world. In this paper, we describe two new Haliclona spp. collected at Pernambuco, Alagoas and Bahia States (north-eastern Brazil, between 08°46′S and 13°56′S). Haliclona (Reniera) chlorilla sp. nov. is a dark green or black coloured, delicately-branched species; and Haliclona (Soestella) peixinhoae sp. nov., a beige-coloured, tubular species, where tubes frequently bear large thorns and possess a conspicuous sub-superficial meandering reticulation. These species highlight the importance of including ex-situ collections in compiling baseline data, as both were already present in scientific collections by the 1980s and 1990s.

A new Brazilian endemic Monanchora is described, M. brasiliensis sp. nov. It is clearly distinct from any other species in the genus by the monodentate shape of its anchorate isochelae, and its smooth, centrotylote and strongyloid microrhabds. Monodentate anchorate isochelae are relatively common, normally abundant, and represent the main diagnostic character for recognizing the new species, but microrhabds are usually rare and may be even absent. Monanchora brasiliensis sp. nov. can be further differentiated from other Atlantic species of the genus in eventually showing tetralobate branches and a skeleton formed by well-defined honey-coloured spongin fibres. The affinities of the new species with other crambeids and the nature of anchorate isochelae, microrhabds as well as the megascleres in defining Monanchora are discussed. An amended diagnosis for the genus is proposed.

Descriptions of hexactinellid sponges collected by the RV ‘Marion Dufresne’ MD55 expedition on the Vitória–Trindade seamounts chain (off Espírito Santo State, south-eastern Brazil) in 1987 and stored in the MNHN (Muséum National d'Histoire Naturelle in Paris) are presented. Hyalonema (Cyliconema) conqueror sp. nov. (the first finding of this subgenus in the Atlantic Ocean) and H. (Prionema) dufresnei sp. nov. (the second record of this subgenus for the Atlantic Ocean) are described as new species. The holotype of H. (C.) conqueror sp. nov. was collected with a ROV at Campos Basin (off Rio de Janeiro State, south-eastern Brazil), while the paratypes originated from Vitória–Trindade seamounts chain and off Bahía State (eastern Brazil). Other hexactinellids reported here, Farrea sp., Sarostegia aff. oculata, Aphrocallistes aff. beatrix, Dactylocalyx aff. subglobosus and Euplectella suberea were known before to be widely distributed in the Atlantic Ocean. The total number of hexactinellid sponges known from Brazil has risen to 15 and from the south-western Atlantic to 23.

Calcareous sponges (Calcarea: Calcinea) are being described, for the first time, from São Paulo State, Brazil. A total of five species are described, two of which are new to science (Clathrina alcatraziensis sp. nov. and Leucascus roseus sp. nov.). The remaining three species have their distribution widened (Clathrina aurea, C. conifera and C. tetractina).

Three new species of Crambe are described from the upper and middle-southern coast of Chile, south-east Pacific. Crambe chilensis sp. nov. and C. amarilla sp. nov. are astroclone bearing species, while C. maldonadoi sp. nov. has sphaeroclones as asterose desmas. Morphological characters of Crambe were re-evaluated to consider this unsuspected high diversity of Crambe in the south-east Pacific. The main characters for the distinction of Chilean species as well as of other Crambe species were the live-colour; the shape and size of asterose desmas and (sub)(tylo)styles; the shape, number of categories and size-range of anchorate isochelae; and the presence/absence and dimensions of spined microxeas. An identification key for the Crambe of the world is provided. If astroclone and sphaeroclone desma-bearing species groups would represent two distinct evolutionary lineages, then the south-eastern/eastern Pacific Region would have been occupied by two evolutionary lineages with distinct life histories. The relatively high diversity of Crambe in the Chilean temperate coast, together with its occurrence in New Zealand's Oligocene, is suggestive of a likely wide distribution in Panthalassa, which contrasts to earlier suggestions of wide distribution in the Tethyan Realm only.

This article reports on a new species originating from the northern Chilean fjord region, which argued for the resurrection of Cornulotrocha, here classified as a new subgenus of Clathria, for sponges with choanosomal acanthostyles, ectosomal quasidiactinal monactines and rosettes of palmate (an)isochelae. Clathria (Cornulotrocha) rosetafiordica sp. nov. was collected at 23 m depth at Quintupeu fjord (∼42°S), and is unique within this very large genus, in possessing rosettes of palmate anisochelae. The new species is compared to the only other known Clathria (Cornulotrocha), viz. C. (Cornulotrocha) cheliradians n. comb.; to the single other Clathria known with anisochelae, viz C. (Thalysias) dubia; to other crustose Clathria from southern South America, the subantarctic and Antarctic areas; and also to other sponges bearing rosettes; and is considered clearly distinct from all. The phylogenetic significance of rosettes is discussed, a likely adaptive value being discarded in view of the variable location of such structures in the distinct poecilosclerid taxa in which they occur.

A species of the genus Amorphinopsis is described for the first time for the Atlantic Ocean. The new species was described based on the study of 25 specimens, collected in the area of the São Sebastião Channel and its environs (northern sector of São Paulo State coastline) and in the Cabo Frio region (Rio de Janeiro State). The form is massive cushion-shaped, lobate, occasionally encrusting. The megascleres are styles [160–260 (N=20)/5–10 (N=10) μm; length/thickness] and oxeas [150–900 (N=100)/5–18 (N=20) μm]. Amorphinopsis atlantica sp. nov. differs from the other species of Amorphinopsis by its colour, dark-greyish-green with or without yellow tinges on the exposed surface, and the smaller size of its oxeas. Amorphinopsis excavans is the closest species to the Brazilian material, but can still be set apart by a series of smaller traits, such as oxeas and styles never overlapping (the smaller oxea is always larger than the larger style).