A new Mediterranean ‘lithistid’ sponge, Aciculites mediterranea sp. nov. (Porifera: Demospongiae) from a dark marine cave in Sardinia

Abstract

A first record of the genus Aciculites in the Mediterranean Sea and the description of Aciculites mediterranea sp. nov. are here presented from a faunistic survey in a dark shallow marine cave of the north-western Sardinian karstic area. The new species is characterized by a massive cerebellum-like growth form, and a peculiar distribution of inhalant and exhalant areas, respectively, in depressed and elevated portions of the sponge surface. Oscules show a long narrow atrial cavity. Ectosomal skeleton is made of tangential anisostrongyles on elevated areas, and more or less vertical tufts of anisostrongyles in depressed inhalant areas. Anisostrongyles are smooth or with tips ornated by irregular tubercles. Sigmaspire microscleres are lacking. Choanosomal skeleton with tubercled irregular rizhoclone desmas and few scattered and variably oriented anisostrongyles. A comparative analysis of Aciculites mediterranea sp. nov. versus morphological diagnostic traits, geographical range and habitat of the species hitherto ascribed to Aciculites confirms that the peculiar distribution of the genus supports its relic condition of an ancient Tethyan fauna in the Mediterranean Sea.

Amphipods from marine cave sediments of the southern Iberian Peninsula: diversity and ecological distribution

“…The existence of species with disjunct distributions in distant marine caves raises questions about how these species can keep their metapopulation dynamics. It has been suggested that a stepping stones model, with larvae moving passively from one cryptic habitat to another, was plausible for some cases (Manconi et al 2006(Manconi et al , 2009. Recent discoveries highlight that these cave-exclusive species are often deepwater species that have denser populations in bathyal areas but are also able to colonize shallow cavernicolous habitats (Bakran-Petricioli et al 2007).…”

Lithistid sponges from submarine caves in the Mediterranean: taxonomy and affinities

“…One of the particularities of these caves is a common occurrence of lithistid sponges. Lithistid sponges are rare in the Mediterranean Sea and only 9 species of 9 genera have been reported so far (see detailed review in Manconi et al, 2006;Manconi and Serusi, 2008, and references herein). Those cited from submarine caves are even less common and are poorly studied.…”

“…Those cited from submarine caves are even less common and are poorly studied. Only six lithistid species of six genera were reported from submarine caves: these are Discodermia polydiscus (Bowerbank, 1869) (Theonellidae Lendenfeld, 1903) and Corallistes masoni (Bowerbank, 1869) (Corallistidae Sollas, 1888) from the caves around Marseille (Pouliquen, 1969a(Pouliquen, , b, 1972, Gastrophanella phoeniciensis Perez, Vacelet, Bitar andZibrowius, 2004 (Siphonidiidae Lendenfeld, 1903) and Microscleroderma lamina Perez, Vacelet, Bitar andZibrowius, 2004 (Scleritodermidae Sollas, 1888) from a Lebanese cave (Perez et al, 2004), Aciculites mediterranea Pisera, 2006 (Scleritodermidae Sollas, 1888) from a northern Sardinian cave (Manconi et al, 2006), and Neophrissospongia nana Serusi, 2008 (Corallistidae Sollas, 1888) from a western Sardinian cave. The species Discodermia polydiscus and Coral-listes masoni were also recorded from the deep sea in the bathyal zone (Vacelet, 1969;Magnino et al, 1999, respectively).…”

Rare sponges from marine caves: discovery of Neophrissospongia nana nov. sp. (Demospongiae, Corallistidae) from Sardinia with an annotated checklist of Mediterranean lithistids

“…Nine species belonging to 9 genera of 6 families have been until now recorded in the Mediterranean Sea (Appendix 1) (Topsent 1892a(Topsent , 1893(Topsent , 1925Vacelet 1960Vacelet , 1969Pouliquen 1969Pouliquen , 1972Pulitzer-Finali 1970Pansini 1992Pansini , 1995Boury-Esnault et al 1994;Magnino et al 1999;Pansini and Longo, 2003;Perez et al 2004;Longo et al 2005;Manconi et al 2006;Zibrowius and Taviani 2005). Th e taxonomic richness appears to be notably higher in the tropics (Lévi 1991;Pisera and Lévi 2002;Schlacher-Hoenlinger et al 2005) whereas the low values in the Mediterranean may be explained by the occurrence of extinction phenomena due to harsh environmental/climatic changes during the history of this basin (e.g.…”

“…All Mediterranean records refer to genera characterised by a highly disjunct distribution with a spot-like pattern in tropical/subtropical latitudinal ranges of the Atlantic, Indian and western Pacifi c oceans. Th ese taxonomic and biogeographic patterns suggest the condition of lithistids as remnants of an ancient Tethyan fauna (Reid 1967;Perez et al 2004;Manconi et al 2006;Pisera and Vacelet 2006).…”