Conservation of marine biodiversity: biology, taxonomy, biogeography and sustainable development of target sponges

The assessment of biodiversity is the basis to plan any activity of conservation.This doctoral thesis aims to contribute to sponges global diversity assessment focusing on cryptic environmentsi.e. caves. A multidisciplinary approach, combining morphological, molecular, ecological and statistics techniques, attempts to solve current issues in taxonomy, biogeography and ecology of some taxa of Mediterranean Porifera with high conservation value. Other aims are to clarify the main adaptive strategies of some target taxa to colonize caves.The geographic range and variation in size and shape of skeletal spicules of two cave-dweller species belonging to the Mediterranean endemic genusPetrobiona(Calcarea: Lithonida: Petrobionidae) are investigated using traditional and geometric morphometric approaches.A checklist of sponge fauna from anchialine environments represents a contribution to the biological knowledge of extreme caves at global scale, and a multi-year study of cave-dwelling faunal assemblages (composition, structure and topographic distribution) focus on the Bue Marino Cave (Sardinia, Orosei Gulf) as model in relation to the physico-chemical water parameters, with notes on the adaptive strategies of sponges.Integrative taxonomy by morphological and genetic approaches is performed to describe a new species from the Bue Marino Cave and to attempt a phylogenetic reconstruction of the genusProtosuberitesusing three different markers (COI, 18S rRNA, and 28S rRNA).