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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 2797

Walter Koste; [Rotatorien aus Gewassern am Mittleren Sungai Mahakam, einem Uberschwem-mungsgebiet in E-Kalimantan, Indonesian Borneo]. Osnabrucker naturwiss.Mitt. 14:91-136, 1988

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In this paper, the results are published of the examination of the first plankton samples collected in order to study the Rotifers of Borneo. This island, the third in dimensions of the earth, and called at the moment Kalimantan, was originally covered with tropical rain forest. We met with 158 taxa, which are summarized in a species list. 155 taxa have been identified to species level. Three groups of artefacts, due to formal contraction, belonging to the genera Cephalodella and Ptygura, and to the order Bdelloidea, could not be identified. The great diversity of species in the beginning of the wet season is not unusual in shallow tropical waters; it has already been encountered by the author in Amazon and in Paraguay as well as in billabongs of Northern Australia. Mostly creeping littoral species are concerned, with an important contribution of species from the polysaprobe water zone. In this context, Dicranophorus caudatus and the soft-bodied species of the genus Mytilina, e.g. M. acanthophora, M. trigona and M. bisulcata, as well as the Bdelloids Rotaria rotatoria and R. neptunia are characteristic. On the other hand, 41 planktonic Rotifer species show that locally planktonic and semi-planktonic species may occur in great abundance, even in periods of low water level. This is the case of, among others, the tropical species Anuraeopsis coelata, Asplanchna tropica, Brachionus falcatus, Collotheca ornata natans, a new form of Euchlanis dilatata, Hexarthra insulana and Keratella tropica, next to the well-known cosmopolite tychoplanktonic species Brachionus calyciflorus s.l., Filinia longiseta, Polyarthra vulgaris and Trichocerca similis. In a separate apart of this publication, 32 Rotifer species are figured, the biogeography or the taxonomy of which is worth mentioning. Among them, species are concerned which up to now were unknown to SE-Asia, five novae formae of known species and two up to now unknown novae species: Brachionus schwoerbeli and Lecane braumi.