Macrofaunal communities in the Gioia Canyon (Southern Tyrrhenian Sea, Italy)

Submarine canyons play pivotal roles in the physical, biological and ecological processes of coastal areas, especially in closed or semi-closed basins as the Mediterranean Sea, influencing the biodiversity and the abundance of the benthic fauna. On February 2013, during the Tyrrhenian Gravity Flows (TyGraF) campaign, samples have been collected along the Gioia Canyon Basin (Italy) with the aim to describe the taxonomical composition and the abundances of the macrobenthic assemblages, filling the gap of knowledge in this area. A total of 93 taxa were identified, and the Annelida was the phylum with the highest number of specimens and most diversified (46 taxa). The polychaetes Sternaspis scutata, Prionospio cirrifera and Monticellina sp., the bivalves Thyasira sp.1 and Saccella commutata and the amphipods belonging to the genera Ampelisca and Harpinia showed the highest densities in the studied area; however, results suggest low values of the abundances of the macrobenthos if compared with those generally reported for other canyons, both inside and outside the Mediterranean Sea. The marine biotic index (AMBI) highlights that the canyon system and the surrounded area were slightly disturbed and characterized by a high percentage of tolerant taxa. This study is the first baseline for future analyses of the macrobenthic communities of this area

Comparison between the sponge fauna living outside and inside the coralligenous bioconstruction. A quantitative approach

Coralligenous habitat results from a multi-stratified accumulation of crustose coralline algae and animal builders in a dynamic equilibrium with disruptive agents. The result is a complex architecture crossed by crevices and holes. Due to this three-dimensional structure, coralligenous may host a rich and diversified fauna, more abundant than any other Mediterranean habitat. Unfortunately, very few data are available about the cryptic fauna that lives inside the conglomerate. As already reported for coral reefs, the cryptic fauna plays an important role in the exchange of material and energy between water column and benthic assemblages. Here we compare the sponge community present inside and outside the coralligenous framework of Portofino Promontory (Ligurian Sea) at different depths (15 and 30 meters) not only in terms of taxonomic diversity but for the first time also in term of biomass. Sponges present on the surface of each block were collected, weighed and identified; after blocks dissolution in HCl, target cryptic sponges were separated from other organisms, weighed, and identified. We recorded a total of 62 sponge species. The average number of sponge taxa occurring outside the coralligenous accretions is lower than the number of taxa identified inside. This pattern is confirmed also regarding sponge biomass. These results underlines that studies focused on coralligenous functioning should take in account the important contribution of cryptic fauna, as recently evidenced also for tropical reef habitats

Biology of the massive symbiotic sponge Cliona nigricans (Porifera: Demospongiae) in the Ligurian Sea

Volume: 44Start Page: 77End Page: 8

A new species of Coelocarteria (Porifera, Demospongiae) from Sulawesi, Indonesia.

The present study deals with a new species of the genus Coelocarteria Burton, 1934, to which only two species C. singaporensis (Carter, 1883) and C. spatulosa Bergquist & Fromont, 1988 were till now attributed. The genus has been recently allocated within the sub-order Mycalina (Hajdu et al., 1994), family Isodictyidae Dendy, 1924 on the basis of the reticulate architecture of the choanosome and of the presence of palmate isochelae (Hajdu & Lobo Hajdu, 2002). It has a tropical, Indo-West Pacific distribution, with a single doubtful record from Tristan da Cunha (southern Atlantic Ocean) (Ridley & Dendy, 1887). It occurs both in superficial and deep waters. A new sponge species Coelocarteria agglomerans sp. nov. (Isodictyidae: Mycalina: Poecilosclerida) is described from the reef slopes of Bunaken National Marine Park, North Sulawesi, Indonesia. The new species can be separated from the other two congeneric species: C. singaporensis and C. spatulosa by several characters concerning sponge surface, fistule shape, form and size of the spicules and habitat. In detail it differs from C. singaporensis in the presence of strongyles instead of oxeas as main megascleres and of spines in the shaft of palmate isochelae. It differs from C. spatulosa in the absence of characteristic fistules with spatula shaped hoods and in spicule size, because both categories of strongyles and palmate isochelae are remarkably larger in the latter