Types of cladoceran species described by Sven Ekman in the Swedish Museum of Natural History, with redescription of Daphnia cavicervix Ekman, 1900 (Daphniidae, Anomopoda, Cladocera) ALEXEY A. KOTOV 1 & MARIA A. GOLOLOBOVA 2 1 A. N. Severtsov Institute of Ecology and Evolution, Moscow, Russia, and 2 Department of Bioengineering and Bioinformatics, M. V. Lomonosov Moscow State University, Moscow, Russia (Accepted 27 June 2005) Abstract In the course of our examination of samples of Cladocera from South America and subantarctic islands in the collection of the Swedish Museum of Natural History, Stockholm, we found some type material of Sven Ekman, unrecognized earlier, as well as other samples described in his publications (Ekman 1900, 1905). A single specimen of Pleuroxus scopuliferus Ekman, 1900, apparently seen by its author, is re-deposited as the lectotype, while the neotype of this taxon earlier selected by Frey (1993) must be rejected according to ICZN (2000). Daphnia cavicervix Ekman, 1900 is redescribed based on numerous parthenogenetic, ephippial females and males, and lectotype and paralectotypes are selected. Some recent problems of systematics of Daphnia in South America are discussed. Keywords: Anomopoda, Cladocera, Daphnia, South America, systematics, taxonomy Introduction Among cladoceran investigators at the end of the 19th and beginning of the 20th century, Sven Ekman was a remarkable person. He did not publish many articles (Ekman 1900, 1905), but, in contrast to many papers of that time, his descriptions of animals were relatively detailed. His contribution to study of the cladoceran fauna of the southernmost portion of the South American continent and subantarctic islands is specially well known. Predominantly, Ekman obtained samples for his investigations from E. Norenskio ¨ld, one of the most famous travellers and investigators of the southern hemisphere of that time. Some of Ekman’s specimens were re-examined by Ru ¨ he (1914), and then the collection was lost to the attention of cladoceran investigators until Frey’s (1988) revision of subantarctic Alona, including A. bucobensis var. subantarctica Ekman, 1905. We became interested in Ekman’s samples through efforts to redescribe Ilyocryptus brevidentatus Ekman, 1905 (see Kotov et al. 2002). In the course of our examination of samples from the Swedish Museum of Natural History, Stockholm (SMNH), we found some type material of Sven Ekman, unrecognized earlier. Correspondence: Alexey Kotov, A. N. Severtsov Institute of Ecology and Evolution, Leninsky Prospect 33, Moscow 119071, Russia. Email: golokot2000@mail.ru Published 28 October 2005. Journal of Natural History, 2005; 39(33): 3059–3074 ISSN 0022-2933 print/ISSN 1464-5262 online # 2005 Taylor & Francis DOI: 10.1080/00222930500240015