Taxonomy of some Indian and Pacific oceans Corticium, with the description of three new species from Western Australia (Porifera: Homosclerophorida).

The sponge genus Corticium has important evolutionary significance and great pharmacological potential, but its diversity remains poorly known. In this contribution we redescribe two poorly-known Indian and Pacific oceans species, viz., Corticium simplex and C. bargibanti, and describe three new species of Corticium from Western Australia. We observed for the first time the presence of rare calthrops in C. simplex, which has a wide distribution and may be a species complex. The three new species are mainly characterized by their spiculation: Corticium furcatum sp. nov. has large calthrops and exclusive candelabra with bifurcated rays in the apical actine; C. monolophum sp. nov. has large monolophose calthrops, smooth calthrops and candelabra; and C. verticillatum sp. nov. has acanthocalthrops with verticillated spines, which are exclusive to this species within the genus. The diversity of Corticium is raised to 11 species worldwide, but it still remains highly underestimated. A key to all valid species is here provided.

New cave-dwelling Plakina (Plakinidae, Homoscleromorpha, Porifera) from Martinique Island (French Antilles).

Knowledge of homoscleromorph sponge biodiversity has greatly improved during the last decade thanks to the increasing use of integrative taxonomy and extensive exploration of remote ecosystems. Indeed, recently described species have mostly been small sponges living in dark and near-impenetrable habitats. This work integrates morphological, cytological, ecological and molecular data to describe a new species belonging to the Plakina genus. Plakina doudou sp. nov. was found first during close inspection of photographs taken previously in a submarine cave on Martinique Island, where several new species had already been revealed. The new species lives in syntopy with P. arletensis. It is thinly encrusting, whitish in vivo, and its skeleton harbors a unique composition of diods, triods, monolophose triods and monolophose, dilophose and trilophose calthrops. Sequencing of a portion of the mitochondrial gene cox-1 indicates that the new species belongs to a well-supported clade containing the Mediterranean P. crypta and P. trilopha. However, at the time of publication of this work, we have not yet managed to identify synapomorphies that would support the different clades of Plakina. This genus includes a total of 39 species to date, of which 10 have been recorded in the Western Tropical Atlantic, and 4 in Caribbean submarine caves.

New sciaphilic plakinids (Porifera, Homoscleromorpha) from the Central-Western Pacific.

The sponge class Homoscleromorpha is a key model for the evolutionary biology of the Metazoa but its diversity remains poorly known. Here we describe six new species of the homoscleromorph family Plakinidae found in shaded habitats (submarine caves, tunnels and overhangs) of New Caledonia and Marquesas Islands, Central-Western Pacific. The new species belong to four genera: Corticium (Corticium vaceleti sp. nov.), Plakina (Plakina finispinata sp. nov.), Plakinastrella (Plakinastrella osculifera sp. nov., Plakinastrella nicoleae sp. nov. and Plakinastrella pseudolopha sp. nov.), and Plakortis (Plakortis ruetzleri sp. nov.). Plakinastrella pseudolopha sp. nov. has a novel spicule type called here 'pseudolophose spicules'. The diversity of Homoscleromorpha is raised to 50 species in the Pacific Ocean and 120 spp. worldwide.

A new cave-dwelling species of Plakina (Porifera: Homoscleromorpha) from Crete, Greece (South Aegean Sea).

Recent studies showed a high diversity of the class Homoscleromorpha (Porifera) in the North Aegean Sea. In the South Aegean Sea, however, only one species of the homoscleromorph genus Plakina, P. weinbergi, was reported so far. Here we describe a new species of Plakina from a marine cave in the South Aegean Sea (Crete Island, Greece), viz., Plakina strongylata sp. nov. The new species is white, fragile, with a highly folded surface, and its spicules are diods, triods and calthrops with rounded extremities plus mono- and dilophose diods, mono-, di- and trilophose triods, and mono-, di, tri- and tetralophose calthrops. The number of Plakina species worldwide is raised to 35, of which nine occur in the Aegean Sea.

Two new species of Halichondrida (Demospongiae) and the first record of Phycopsis and Ciocalapata for Brazil.

Two new species of the genera Phycopsis and Ciocalapata are described from the shallow waters off the Brazilian coast. This is the first record of Phycopsis in South Atlantic, with Phycopsis styloxeata sp. nov. being the only species of the genus that presents three categories of spicules: two of styles and one of oxeas. Ciocalapata, here represented by Ciocalapata minuspiculifera sp. nov., displays smaller oxeas and styles when compared to its congeneric C. amorphosa (Ridley & Dendy, 1886). The definition of this genus was modified and its geographical and bathymetric distributions now extend from the coast of Argentina to the northeastern coast of Brazil (state of Bahia) and from deep (1.097 m) to shallow (14-20 m) waters, respectively.