Revision of the Recent Alvania scabra (Philippi, 1844) complex (Mollusca, Gastropoda, Rissoidae) from the Mediterranean Sea with the description of a new species.

Herein we revise several Recent Mediterranean species of the rissoid genus Alvania Risso, 1826: Alvania scabra (Philippi, 1844), Alvania sculptilis (Monterosato, 1877), Alvania sororcula Granata-Grillo, 1877, Alvania lucinae Oberling, 1970, Alvania josefoi Oliver Templado, 2009 and Alvania scuderii Villari, 2017. They represent a rather homogeneous group of morphologically similar species, referred to as the Alvania scabra complex, which includes also some other species from the northeastern Atlantic. We designate a neotype for Rissoa scabra Philippi, 1844 and a lectotype for Rissoa oranica Pallary, 1900 to stabilize the use of the names.

An approach based on the total-species accumulation curve and higher taxon richness to estimate realistic upper limits in regional species richness.

Most of accumulation curves tend to underestimate species richness, as they do not consider spatial heterogeneity in species distribution, or are structured to provide lower bound estimates and limited extrapolations. The total-species (T-S) curve allows extrapolations over large areas while taking into account spatial heterogeneity, making this estimator more prone to attempt upper bound estimates of regional species richness. However, the T-S curve may overestimate species richness due to (1) the mismatch among the spatial units used in the accumulation model and the actual units of variation in β-diversity across the region, (2) small-scale patchiness, and/or (3) patterns of rarity of species.

Effects of offshore platforms on soft-bottom macro-benthic assemblages: a case study in a Mediterranean gas field.

The exploitation of fossil fuels in the Mediterranean Sea will likely lead to an increase in the number of offshore platforms, a recognized threat for marine biodiversity. To date, in this basin, few attempts have been made to assess the impact of offshore gas and oil platforms on the biodiversity of benthic assemblages. Here, we adopted a structured experimental design coupled with high taxonomic resolution to outline putative effects of gas platforms on soft-bottom macrofauna assemblages in the North Ionian Sea.