title: Revision of the Holarctic genus Rhynchotalona Norman, 1903 (Anomopoda: Chydoridae).
abstract: We revise the Holarctic genus Rhynchotalona Norman, 1903 (Anomopoda: Chydoridae). Palaearctic R. falcata (Sars, 1862) is redescribed, including morphology of thoracic limbs and gamogenetic stages. North American populations previously identified as R. falcata, revealed two new species of the genus. R. weiri sp. nov. differs from R. falcata in smaller size, much shorter rostrum, different shape of main head pore and different morphology of postabdomen in male and female. R. longisteta sp. nov. differs from R. falcata in long posterior setae of the valve postero-ventral portion. Both new species also differ from each other and from R. falcata in the morphology of thoracic limbs. Our data suggests that the Palaearctic R. falcata is absent in North America, confirming Frey's non-cosmopolitism paradigm for the Chydoridae. The genus diagnosis is emended, taking into consideration the newly described taxa. A key for species determination is provided.
authors.affiliation: Department of Invertebrate Zoology, Biological Faculty, M.V. Lomonosov Moscow State University, Leninskie Gory, Moscow 119991, Russia.; Email: artemsinev@yandex.ru.
authors.forename: Artem Y
authors.initials: AY
authors.lastname: Sinev
authors.affiliation: A. N. Severtsov Institute of Ecology and Evolution, Leninsky Prospect 33, Moscow 119071, Russia.; Email: alexey-a-kotov@yandex.ru.
authors.forename: Alexey A
authors.initials: AA
authors.lastname: Kotov
mesh_terms: D063147:Animal Distribution; D000825:Animal Structures / Q000033:anatomy & histology / Q000254:growth & development; D000818:Animals; D049628:Body Size; D033361:Cladocera / Q000033:anatomy & histology / Q000145:classification* / Q000254:growth & development; D005260:Female; D008297:Male; D009656:North America; D009929:Organ Size