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The freshwater littoral comprises a mosaic of habitats structured at several scales by a combination of hydrophyte architecture and physiology. Within this complex environment littoral invertebrates should distribute themselves to maximize fitness: that is, for sessile animals selection of permanent substrata is critical, while distribution of motile (periphytic) animals should follow predictions of Ideal Free Distribution theory. Here we explore the relationships between littoral rotifers and hydrophytes by conducting nestedness analyses on 10 published datasets (7 sessile; 3 periphytic); one dataset each of microcrustaceans and insects were included for comparison. We used four metrics to assess nestedness: mean matrix temperature (T); counts of discrepancy shifts and species segregation; and percent singletons. Six sessile rotifer datasets exhibited nestedness (T = 9.25–30.2°, supported by ≥2 null models; the other metrics varied widely). Our results indicate that distribution of sessile rotifers and periphytic insects was highly structured, but until more data is available little can be said about the distribution of the periphytic rotifer or microcrustacean community structure. Sessile rotifer species possessing idiosyncratic temperatures (T>T +1.5 SD) exhibited a trend toward a record of cosmopolitanism. Important idiosyncratic hydrophytes included Ceratophyllum, Chara, and Utricularia. Two of the three periphytic, rotifer datasets exhibited nestedness (T = 19.2°, 39.9°), but each was supported by only one of the four null models. The periphytic microcrustaceans did not show nestedness, while the insects did (T = 15.5°; supported by four null models). The three other metrics varied considerably among the periphytic datasets, showing no discernable pattern.

To contribute to the biogeographical knowledge of rotifers, we critically re-evaluate the species of Lecanidae recorded from Thailand. We report on a number of rare (L. armata Thomasson, L. bulla diabolica Hauer, L. chinesensis Zhuge and Koste) and one new species of Lecane. Lecane latissima Yamamoto is recognized as the senior synonym of Lecane thailandensis Segers and Sanoamuang, L. kostei De Ridder is reestablised as valid name for the cold-water bipolar taxon formerly referred to as L. latissima. Some dubious and dated records of taxa are reconsidered. In total, we confirm 92 species of Lecane from the country, which is almost half of the world's diversity of the taxon, and a limited degree of endemics to various scales, from countrywide to Paleotropical. These results are in accord with the moderate endemicity model of distribution and diversity patterns in microscopic organisms. A potential new avenue of research may be to unravel cryptic diversity in species complexes such as the L. ludwigii, L. lunaris, L. bulla, L. leontina and L. quadridentata species groups as models of tropical and subtropical micrometazoans. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

During August 1999, the authors conducted a sampling campaign in the PDR Laos, in order to contribute to the chorology of rotifers in the region. Two samples, collected from a rice paddy and an adjacent pond near Vientiane, Laos, contained a total of 135 rotifer species including several that appear new to science or that warrant taxonomical or biogeographical comments. No new species can be named, but Cephalodella boettgeri Koste and Floscularia armataSegers are recorded for the second time ever after their description from South America, and Parencentrum lutetiae (Harring and Myers) and Polyarthra luminosaKutikova are new to Southeast Asia. This raises the number of rotifers recorded from Laos from 9 to 130. The diversity recorded is remarkable, especially when compared with that of similar habitats in the Thai part of the floodplain of River Mekong and its tributaries. Different agricultural practices may account for the difference in species richness. Similar highly diverse rotifer faunas are known to occur in natural, tropical and subtropical floodplain systems only. This accords with the view that rice paddies can be regarded as artificial wetlands or floodplain systems, which, if managed taking biodiversity concerns into account, may have a potential for the conservation of freshwater biodiversity. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Two-hundred and fourty-six freshwater and saline-alkaline waters in Inner Mongolia, P.R. China were surveyed for Brachionidae. Twenty-nine brachionid morphospecies (33 taxa) are recorded, four are new to China. Some data on their distribution, and comments on selected taxa are provided. Brachionus asplanchnoides (stat.nov.) is reinstated at the morphospecies level. We suggest that this taxon may be used in aquaculture, considering that, by its large size, it extends the size range of brackish-water Rotifera potentially available as food for fish larvae.

Results are presented on a study of the momentary species diversity of Rotifera in Laguna Bufeos, a flood plain lake of the Ichilo River in Bolivia. A total of 104 morphospecies of monogonont Rotifera were identified from three samples collected on June I, 1997. The species record includes 11 % Neotropical endemics, 5 % pantropical and 13 % tropicopolitan taxa. Four taxa, viz. Aspelta lestes HARRING and MYERS, 1928 ; Colurella denticauda CARLIN, 1939: Ptygura intermedia (DAVIS, 1867) and Trichocerca kostei SEGERS, 1993 are newly recorded from South America, 67 morphospecies are new to the Bolivian fauna. Notes are added on some selected taxa. Brachionus amazonica KOSTE and ROBERTSON, 1983 (stat. nov.) is elevated to morphospecies rank.