Reef building Mediterranean vermetid gastropods: disentangling the Dendropoma petraeum species complex

Abstract

A previous molecular study has revealed that the Mediterranean reef building vermetid gastropod Dendropoma petraeum conforms a complex of at least four cryptic species with non-overlapping distribution areas. Once detected specific genetic differences, ‘a posteriori’ searching for phenotypic characters has been undertaken to differentiate cryptic species and to formally describe and name them. The name D. petraeum (Monterosato, 1884) should be restricted to the species of this complex distributed around the Central Mediterranean (type locality in Sicily). In the present work we redescribe this taxon under the older valid name D. cristatum (Biondi, 1857), and we describe the new species of this complex distributed in the western Mediterranean. These descriptions are based on a comparative study focusing on the protoconch, teleoconch, external and internal anatomy. Both species can be only distinguished on the basis of non-easily visible anatomical features. Further, protoconchs differ in size and sculpture. On the other hand, some differences between both species are evidenced in features of the intracapsular larval development: the number and size of the egg capsules brooded per female at the same time, the number of egg/embryos per egg capsule, egg diameter and type of intracapsular nutrition.