Revision of Aploparaksis Clerc, 1903 (Cestoda: Cyclophyllidea, Aploparaksidae), with keys to the species of the genus

Abstract

This article reviews the primary results of a taxonomic revision of species of the genus Aploparaksis Clerc, 1903 (Cestoda: Cyclophyllidea: Aploparaksidae), which are widespread parasites of birds. We consolidate a deep, primarily Russian, literature that has not been easily accessible, including insights from the recent monograph of Bondarenko & Kontrimavichus (2006a). A revision of Aploparaksis has been based on an extensive review of the literature and on the study of diverse specimens from the Palearctic (Lithuania, European and Asian parts of Russia) and the Nearctic (Alaska) regions assembled from our field collections. We also conducted the re-examination of type and voucher specimens from various museums and institutions in Russia, Europe, and the USA, and material from the personal collections of several scientists. Taxonomic conclusions in the revision combine observations of morphological characters for adults and data regarding metacestode ontogeny and life cycles of 36 species of Aploparaksis. The validity of 58 species of Aploparaksis among the 102 described is confirmed. Summaries for each valid species include: taxonomic synonyms, a range of both definitive and intermediate hosts (if known), site within the hosts, geographical distributions, morphological modifications of the cysticercoid, and a short specific diagnosis with illustrations of the principal characteristics. Collection numbers of specimens deposited in museums are provided for each species. Within the genus, two phylogenetic lineages differing in the topography of female gonads have been recognized: the nominotypical subgenus Aploparaksis (Aploparaksis) Clerc, 1903, with the female gonads arranged along the longitudinal axis of the proglottid, and Aploparaksis (Tanureria) Spassky et Yurpalova, 1968, with the female gonads disposed in a transverse row in the median field of the proglottid. Diagnoses of subgenera and identification keys to their species are presented. A list of invalid species with brief comments regarding each of them is also given. The taxonomic value of ontogenetic features and complex issues concerning the definition of Aploparaksis are discussed.