Pararetinometra lateralacantha Stock and Holmes, 1981 (Cestoda: Hymenolepididae): the first record in the Palaearctic region and comments on its morphology and taxonomy

Abstract

Pararetinometra lateralacantha Stock and Holmes, 1981, known until now only from Alberta, Canada, as a parasite of three species of grebes (Aves: Podicipediformes: Podicipedidae), was found in a wintering Podiceps nigricollis (Brehm) on the Bulgarian coast of the Black Sea. The species is redescribed and illustrated on the basis of both the Bulgarian specimens and specimens from Canada (paratypes). Some corrections or additions to the original description in relation to the characteristics of the rostellum, rostellar sheath, vitellarium, ovary, testes, cirrus sac, cirrus, and vagina are presented. In contrast to a recent opinion, Pararetinometra Stock and Holmes, 1981 is regarded as a valid genus and not as a synonym of Cladogynia Baer, 1937. The geographical distribution of P. lateralacantha is supposed to be circumboreal.