On the ecology of Trichocercidae (Rotifera)

A material consisting of 46 trichocercid rotifers from diverse waters in south and central Sweden was analyzed to reveal their relationships to their substrate. Most species were found in a wide variety of periphytic environments, but a few seemed to be specialized on bogs or psammon, respectively. Several trichocercids are generally regarded as plankters, but some of them obviously invade the open water only on certain occasions. A few species of Trichocerca are registered as indicators of eutrophy, but in some cases only a planktic occurrence may be regarded as indicating. On the other hand, hypertrophic environments are generally avoided. Trichocerca similis prefers polyhumic environments, T. uncinata oligotrophic and running-water conditions. The occurrence is often best explained by studying the food choice.     

On the ecology of Dicranophoridae (Rotifera)

Information on the distribution of 59 dicranophorid rotifers from diverse habitats in south and central Sweden was analyzed to reveal their relationships to their substrate. They were mainly frequenting macrophytic vegetation. Even some species which have previously been regarded as psammobionts were mostly or only found on periphytic substrates. Like other raptorial predators, dicranophorids have a very broad ecological range.     

On the ecology of Lecane (Rotifera)

A material consisting of 49 taxa of Lecane (Rotifera), from diverse waters in south and Central Sweden, was analyzed to reveal their relationships to substrate and habitat. Most species did not show any pronounced preference for any substrate, occurring in several diverse substrates, and especially in periphytic environments. Only a few species seemed to specialize in bog substrates. Some taxa were found, sometimes at a high frequency, on an artificial substrate, white cotton, indicating a high degree of mobility.     

On the ecology of Cephalodella

A material consisting of 66 species of Cephalodella (Rotifera), from diverse waters in south and central Sweden, was analyzed to reveal their possible relationships to substrate and habitat. Most species preferred periphytic environments. Most species have a broad ecological range, only a few being bog specialists. An artificial substrate, white cotton, was colonized by several species, even some without eyes.     

Rotifera from Burundi: the Lepadellidae (Rotifera: Monogononta)

We studied the distribution of Lepadellidae (Rotifera) in freshwater habitats in the floodplain of the River Rusizi in northwest Burundi. Twenty-three species belonging to ColurellaBory de St. Vincent, 1824 (3 species), Lepadella Bory de St. Vincent, 1826 (18 species) and Squatinella Bory de St. Vincent, 1826 (2 species) are recorded, 22 of them are new to Burundi. One of the taxa encountered probably represents an unnamed species. Lepadella arabicaSegers & Dumont, 1993 is recognised as junior subjective synonym of Lepadella eurysterna Myers, 1942 (syn. nov.). Most of the taxa recorded are cosmopolitan or tropicopolitan, two are restricted to the tropical regions of the Old World and Australia, and one, Squatinella lunata Segers, 1993 is an Ethiopian endemic.     

On relation to substrate in sessile rotifers

Information on the distribution of 45 sessile rotifers from diverse freshwaters in south and central Sweden was analyzed to reveal possible relationships to their substrates. Almost all of them showed an exclusively periphytic occurrence. The highest number of species was found on Utricularia, but otherwise it was not possible to correlate rotifer presence to any special macrophyte or category of plants (e.g., fine-leaved or floating-leaved species).     

On a new species of Keratella (Rotifera: Monogononta: Brachionidae)

A new species of planktonic rotifer, Keratella sinensis n.sp.is described from Lake Yaoquan, Heilongjiang, P.R. China. Itprobably also occurs in the Republic of Korea and Japan. The newmorphospecies is characterised by an unusually smooth lorica, andstrongly reduced lateral anterior spines. It is the first exampleof a planktonic freshwater rotifer, endemic to North EastAsia.     

On four new tropical and subtropical Lecane (Lecanidae,Monogononta, Rotifera)

Four new tropical/subtropical species of Lecane are described. L. abanica n. sp. is recorded from Saudi Arabia and the Comoro Islands; L. minuta n. sp. and L. spiniventris n. sp. from the Sultanate of Brunei, and L. nelsoni n. sp. from Brazil. An attempt is made to include characters of the trophi in the diagnosis of these Lecane.     

Freshwater Rotifera from plankton of the Kerguelen Islands (Subantarctica)

During the austral summer 1997/98, a survey was made of a series of freshwater bodies on the Kerguelen Islands, Subantarctica (49° S–69° E), in the area of Port-aux- Français and Val Studer. The rotifer fauna from plankton of 17 lentic freshwaters is listed and commented upon. Species richness (39 taxa) and species diversity are fairly low. Only 6 taxa are euplanktic, the others are facultative plankters or littoral/benthic species. Three of the true plankters found are restricted to the Southern Hemisphere, whereas the rest of the rotifers (apart from two unidentified monogononts) shows a wide-spread or cosmopolitan distribution. Thirty-three taxa are new to the Kerguelen archipelago. A comparison is made with the rotifer assemblages observed on other Subantarctic islands. Taxonomic notes on little known species are added. The validity of Cephalodella gibba microdactyla as separate subspecies is rejected, and Filinia terminalis kergueleniensisis recognized as junior synonym of F. pejleri.     

On Lecane tanganyikae new species (Rotifera: Monogononta, Lecanidae)

A new species of rotifer, Lecane tanganyikae n.sp., is described from the littoral of Lake Tanganyika and some water bodies in the plain of the Rusizi river near Lake Tanganyika, Bujumbura Province, Burundi. The affiliation of the new species, especially in relation to L. elsa Hauer, is discussed.     

On species of the genus Lophocharis Ehrenberg, 1838 (Rotifera: Monogononta) from Uzbekistan

Three species of Lophocharis (Rotifera: Monogononta), collected from lakes and ponds of Uzbekistan, are described. Two are new to science, and one is recorded for the first time from Uzbekistan. Some data on the variability of these species are given.     

Biodiversity of Rotifera in some tropical floodplain lakes of the Brahmaputra river basin,Assam (N.E. India)

One hundred and sixteen species of Rotifera are recorded from seven floodplain lakes of the Brahmaputra basin (northeastern India), the highest rotifer biodiversity recorded from these biotopes in the Indian subcontinent to date. The Australasian Brachionus dichotomus reductus and Lecane batillifer; the Oriental Keratella edmondsoni, Lecane blachei and L. acanthinula; the Palaeotropical Lecane braumi, L. lateralis, L. unguitata, Trichocerca tropis, Testudinella greeni and T. brevicaudata; the Pantropical Brachionus donneri and a rather widely distributed Horaella brehmi represent taxa of biogeographical interest. Three species are new additions to the Indian rotifer fauna and eight are new to the N.E. region. Lecanidae > Brachionidae = Colurellidae > Trichocercidae > Testudinellidae comprise the largest fraction (68.0%) of the examined fauna. Comments are made on the general nature and composition of the rotifer taxocoenosis as well as on acidophilic elements, ecology of various taxa and on the species richness of different lakes.     

Additions to the Lecane fauna (Rotifera: Monogononta) of Thailand

Lecane superaculeata. n. sp. is described from three localities in Thailand. It resembles the small, cosmopolitan L. aculeata (Jakubski, 1912) but is distinguished by its larger size and conspicuous anterolateral spines. Additional records of some recently described Thai Lecane species and comments on Oriental endemics are presented L. eswari Dhanapathi is newly recorded for the country.     

The freshwater zooplankton of Thailand (Rotifera and Crustacea)

A list is given of all zooplankton species hitherto reported from Thailand, based on the author's own observations and on the literature.From a comparison with the fauna of some neighbour countries, it appears that important gaps remain to be filled-in.     

Distribution of Brachionidae (Rotifera,Monogononta) in Inner Mongolian Waters

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.     

Hierarchal gene trees and molecular phylogeny of the Rotifera: use of the Polymerase Chain Reaction (PCR) to dissect ecological and evolutionary patterns

The study of rotifer phylogenies and the analysis of population-level processes historically have been disjunct. This is despite a growing recognition that there are many ways in which rotifer population biologists and ecologists might profit from the availability of a comprehensive phylogeny of the group. New molecular methods which can be applied to a wide range of genetic systems and systematic grades will shortly eliminate the methodological (and perhaps conceptual) distinction between these fields. Of particular importance is the development of the Polymerase Chain Reaction (PCR), a technique of synthetic DNA amplification which produces concentrated preparations of selected genes from complex mixtures of nuclear and mitochondrial genomes. Analysis of PCR products can provide hierarchal genetic comparisons from the level of local rotifer populations through broad evolutionary (at least molecular) phylogenies.     

Zoogeography of the Southeast Asian Rotifera

The distribution and taxonomic composition of Rotifera in Southeast Asia is reviewed. For some countries, records are poor: Brunei, Cambodia and Laos are almost terra incognitafor rotifers (<10 taxa recorded), while the Thai rotifer fauna is the best documented (ca. 310 taxa on record). However, analysis of the available data is impeded by fuzzy taxonomy and the questionable reliability of many records. Most studies focus on the pelagic or littoral of freshwater habitats. Other habitats are largely ignored. Similarly, few studies deal comprehensively with illoricate Monogononta, sessile Flosculariacea and Collothecacea and, especially, Bdelloidea. The genera Lecane, Brachionus and Trichocerca are the best represented, with littoral taxa predominant. Fisheries-related studies dealing with highly productive pelagic environments tend to over report the contribution of Brachionus. Most taxa are thermophilic character, exemplified by the dominance of tropic-centred Lecaneand Brachionus. Some cold-water taxa have been recorded, but the relative climatological homogeneity of the region and low number of studies on high-altitude environments prevent the discrimination of clear latitudinal or altitudinal variation in the distribution of rotifers within Southeast Asia. The majority of Southeast Asian rotifers are widely distributed, including true cosmopolites and thermophilic taxa. There are several local or Oriental endemic Rotifera, mostly Lecane. The American Brachionus havanaensis and Keratella americana appear to have been introduced to the region. The taxonomy of some Rotifera described from the region is commented upon; Brachionus murphyiSudzuki is recognised as senior synonym of B. niwati Sanoamuang et al. (syn. nov.). Some cases of geographical and/or ecological vicariant species-pairs are suggested. The Southeast Asian rotifer fauna contains a sizeable fraction of taxa occurring in the tropical regions of the Old World, most of which also occur in tropical Australia or the Austro-Malayan region. A tropical Australasian faunal component is present, but consists of few taxa only. Hence, affinities between the rotifer fauna of the Ethiopian, Oriental and tropical Australian and Austro-Malayan regions are supported, rather than an affinity between the Indo-Asian or Indo-Malaysian and tropical Australian fauna.     

Diversity of Rotifera (Monogononta) in wetlands of Río Pilcomayo National Park, Ramsar Site (Formosa, Argentina)

The rotifers at this Ramsar site were inventoried for the first time. A total of 114 taxa, belonging 30 genera were found in samples collected from four aquatic habitats in the Río Paraguay basin, in northern Argentina. The rotifer fauna is characterized by a large proportion of cosmopolitan and tropicopolitan species and few species endemic to the Neotropical Region (5%). In the list, 22% of the taxa are new to the Argentine fauna. Colurella sinistra Carlin is a new record to the Neotropical fauna. Ecological and distributional notes on selected species are included.