An unusual, flagellum-bearing hydrobiid snail (Gastropoda: Rissooidea: Hydrobiidae) from Greece, with descriptions of a new genus and a new species

摘要

A new genus and a new species of Hydrobiidae, Agrafia wiktori sp. nov., from the Agrafa Mountains, northern Greece, are described based on the shell, protoconch, radula and male and female reproductive organs. In the protoconch sculpture and female reproductive organs A. wiktori resembles a typical member of Hydrobiidae Sadlerianinae, but the penis with tubular penial gland terminating within the flagellum and extending into the cephalic haemocoele has not been found in any other representative of Hydrobiidae. Instead, it is comparable with the penes and tubular penial glands of some non-hydrobiid Rissooidea (Bithyniidae, Bythinellidae, Amnicolidae, Emmericidae). Analysis of partial sequences of 18S ribosomal DNA and cytochrome oxidase subunit I mitochondrial DNA in A. wiktori place it in Hydrobiidae Sadlerianinae. The evolution of the bifid penis and tubular penial gland is discussed.