Revision of the Genus Mesocyclops Sars 1914 (Copepoda, Cyclopidae) of the World Fauna.
Biology Bulletin
48:1210–1230.
Publication
Available for editors
The genus Mesocyclops Sars 1914, which has hitherto contained too many nominal species, is divided into four subgenera based on the morphological and habitat characteristics. The subgenus Neomesocyclops subgen. n. comprises species almost exclusively living in the New World. The single exception is M. (N.) tenuisaccus (Sars 1927), described from South Africa, which may prove to be a junior synonym of M. (N.) annulatus (Wierzejski 1892), from South America, and could have appeared in Africa as a result of anthropogenic invasion from the New World. The subgenus Tethymesocyclops subgen. n. includes species the distributions of which coincide with the borders of the former subcontinent Gondwana, or rather, the coast of the Tethys Sea, during the separation of Gondwana from Laurasia. These two subgenera contain species with a seta on the inner outgrowth of the basal segment of the first swimming leg pair. This seta is absent in all representatives of the nominative subgenus Mesocyclops s. str. with bare caudal rami and last thoracic somite, as well as in the new subgenus Pilosomesocyclops subgen. n., which has hairs on these structures. Most species of the latter two subgenera live in water bodies of the Old World. Along with a detailed characterization of the identified subgenera, a new species is described: Mesocyclops (Neomesocyclops) frankfiersi sp. n. As part of the revision, species in the two largest subgenera, Neomesocyclops subgen. n. and Pilosomesocyclops subgen. n., are further divided into three sections by the presence of hair-like structures on the last thoracic somite and/or caudal rami. Sections are named after the first species described that shows these characters. Such a structure of the genus makes it possible to simplify significantly the determination of species in the world fauna and, in the future, to supplement the keys after new taxa are described. Compared to the latest faunal overview by Reid and Ueda, the keys presented are extended to the 12 taxa described in the years following the publication of that guide.