The Naticidae (Mollusca: Gastropoda) of Giglio Island (Tuscany, Italy): Shell characters, live animals, and a molecular analysis of egg masses

We investigated the occurence of members of the predatory caenogastropod family Naticidae in the littoral of the island of Giglio, Tuscany, Italy. We recorded a total of 8 species, all but one represented by both empty shells and living specimens. As most studies of Mediterranean naticids are based solely on empty shells, we here provide images of living animals for 7 out of the 8 species encountered; for several of these species this is the first photographic documentation of the animal. Our survey included a systematic collection of egg masses (”sand collars”) which were hatched in the laboratory. The larvae obtained as well as the sand collars themselves were used for molecular analysis of the species based on gene fragments of mitochondrial cytochrome oxidase subunit I (COI), histone 3 (H3), the mitochondrial 16S rRNA (16S), and 18S rRNA (18S). We show that such molecular analysis allows the confirmation of the identity of naticid species without having access to adult specimens or shells. This approach identified one additional naticid species for which no adult specimens or shells were found. Additionally, our molecular analysis allows consideration of naticid phylogeny.