Morphology, anatomy and histology of Flabellina affinis (Gmelin, 1791)(Nudibranchia, Aeolidoidea, Flabellinidae) and its relation to otherMediterranean Flabellina species

摘要

The Atlantic and Mediterranean flabellinid Flabellina affinis (Gmelin, 1791) (Opisthobranchia, Nudibranchia, Aeolidoidea) is examined morphologically, anatomically and histologically with special emphasis on characters which have been widely neglected in recent literature (e.g. the histological structure of the oral glands, typhlosole). The study provides detailed data about all organ systems which are compared to existing data of other authors. The species described as Flabellina affinis by Bergh (1875; 1886) is considered not to be conspecific with the Flabellina affinis examined in this and other studies. Furthermore, Flabellina affinis is compared to other Mediterranean species, especially F. ischitana (Hirano & Thompson, 1990). F. ischitana differs from F. affinis mainly by the structure of the genital system. The phylogenetic trees presented for the genus by Gosliner & Kuzirian (1990) and Gosliner & Willan (1991) are discussed.