Diversidade e distribuição do gênero Alvania (Mollusca, Gastropoda: Rissoidae) no litoral brasileiro

Abstract

The Rissoidae Gray, 1847 are composed of small shells or micro-shells, abundant in the oceans of the world. A great diversity of species of this group is found in areas of low tide and along the coast, where there is a higher occurrence of algae, rocks, corals and other places that provide shelter, however, they also occur in many areas of the deep sea. In Rissoidae, Alvania is one of the most diverse concerning species number with frequent descriptions or re-descriptions within this genus. The aim of this study was to determine the diversity and distribution of Alvania, therefore, describe and expand the knowledge of the fauna in Brazilian littoral, through conquiological analyses, beyond the geographical and bathymetric distribution of the species of this genus. All material is originated from collections of museums, oceanographic expeditions and also material collected in the second half of 2010 and in 2011. Previously, seven species were listed for the west cost of the Atlantic, and in the present study three of these species were not found. We analyzed 3599 specimens belonging to ten species: Alvania auberiana (Orbigny, 1842); Alvania cancapae Bouchet & Warén, 1993; Alvania colombiana Rommer & Moore, 1988; Alvania faberi De Jong & Coomans, 1988; Alvania tarsodes (Watson, 1886), Alvania valeriae Absalão, 1993 and four possible new species: Alvania sp. nov. 1, Alvania sp. nov. 2, Alvania sp. nov. 3, Alvania sp. nov.4.