Cladocera (Crustacea: Branchiopoda) of South East Asia: history of exploration, taxon richness and notes on zoogeography

Abstract

The history of Cladocera studies in South-East Asia is reviewed, beginning from the early start of explorations in the end of the 19 th century by J. Richard and T. Stingelin. In the first half of the 20 th century, extensive research was carried out by V. Brehm, who investigated material collected by the Wallacea-Expedition and the Deutschen Limnologischen Sunda-Expedition. Later, in the 1970-1980s, C.H. Fernando and collaborators, besides a few other researchers, provided a new series of regional studies of the cladoceran faunas together with the systematic revisions of some taxa from tropical Asia. Then and up to present, investigations of the Cladocera have concentrated in Thailand and many species have been revised and described as new to science. In total, 298 taxa of species rank have been recorded in SE Asia but only comparatively few of them (67 taxa; 22.5%) can be regarded good species, of which the valid status has been confirmed by recent studies, while others are synonyms (68; 22.8%) or taxa of uncertain taxonomic status, including those which definitely represent complexes of species (163; 54.7%). Most total taxa of species level and good species are known from Thailand (155 and 54, respectively), followed by Malaysia (plus Singapore), Indonesia, Philippines, Vietnam, and Cambodia in this respect (70-119 total taxa and 23-33 good species respectively). Laos, Burma (Myanmar) and Brunei remain practically unexplored. Only good species were used for the zoogeographic analysis. Of them, about a quarter is known only in SE Asia but more species are distributed in tropical/subtropical/temperate Asia and Australia, others in tropics/subtropics of the eastern hemisphere (17.9%) or even wider. Tropical species, constituting the primary part of the cladoceran fauna of SE Asia, can penetrate the neighboring subtropical and southern temperate zones to a different degree. Only a small fraction of species (7 or 10.5%) here are of more or less northern origin, they are distributed predominantly in the subtropical/southern temperate or in the northern boreal latitudes. Few species are suggested to penetrate SE Asia from the north using the Mekong river and its tributaries. Generally, the cladocerans of SE Asia are poorly known and only continuous extensive taxonomic studies would improve this situation.

Cladocera (Crustacea: Branchiopoda) of Vientiane province and municipality, Laos

“…The three species that we identified here (D. dubium, D. excisum and D. sarsi) were expected in this country, as they are very characteristic of the SE Asian plankton (Korovchinsky, 2004(Korovchinsky, , 2013a(Korovchinsky, , 2013b). There were a few cases where we could not determine the exact species, because there were only a few juveniles in the sample.…”

“…There were only a few publications concerning the Cladocera fauna of other countries (Tanaka and Ohtaka, 2010), sometimes outdated (Shirota, 1966;Thanh et al, 1980). Korovchinsky (2013a) summarised the available information on the SE Asian cladocerans and concluded that among 297 formal species recorded from SE Asia, only 67 species could be regarded as good, while others are junior synonyms or taxa with unclear or/and unconfirmed status in SE Asia. We believe that the present volume (the FISA Proceedings), will significantly contribute to our knowledge on the SE Asian cladocerans, including new Cladocera (Crustacea: Branchiopoda) of Vientiane province and municipality, Laos Korovchinsky (2013a) on the Cladocera of complete SE Asia, by Sinev and Korovchinsky (2013) about Vietnam, and by and about new paludal chydorids of South Thailand.…”

Cladocera (Crustacea: Branchiopoda) of Cat Tien National Park, South Vietnam

“…Several taxonomic groups were revised, and several new species were described Sanoamuang, 2008a, 2008b;Korovchinsky, 2011;Sanoamuang, 2004a, 2004b;Sinev, 2011Sinev, , 2012Sanoamuang, 2007, 2011;Sinev and Kotov, 2012;Van Damme and Sinev, 2013;. At present, the cladoceran fauna of Thailand has proved to be considerably better studied than in any other country of the region -Vietnam, Malaysia, Laos, and Сambodia, while Myanmar still remain especially poorly explored (Korovchinsky, 2013).…”

Front Matter

“…Such studies provide a firm basis within each group for researchers to build on, and in several countries taxonomical efforts spur limnological research. For example, with Korovchinsky (2013) and Rogers et al (2013), we now have a complete overview of all crustacean branchiopods known in literature to date in SE Asia and an idea of what needs to be done, and the same can be said for the freshwater sponges (Manconi et al, 2013) and cave faunas . Alekseev et al (2013) provide a key for Eucyclops in SE Asia, and Van and Van Damme and Sinev (2013) provide new worldwide keys for several cladoceran genera.…”

“…In most cases we lack the basic knowledge on their diversity, geographic distribution and biology. In the waterfleas (Crustacea: Cladocera) for instance, more than 75% of the species recorded from SE Asia need taxonomic revision (Korovchinsky, 2013). Well-equipped natural history museums with representative zoological collections, the basis of biodiversity studies, are still rare in SE Asia, which makes research on the SE Asian freshwater fauna hard for local specialists.…”