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This study investigates the influence of limnological parameters that are known to influence rotifer species richness and composition in temperate areas on two families of monogonont rotifers in a tropical area. We analysed species richness and diversity of the two families from 133 samples taken from several habitat types in Thailand. Coordinates, elevation, pH, temperature, conductivity, salinity and dissolved oxygen were measured and their effect on rotifers assessed. A total of 60 species in 5 genera was recorded from the two families. Latitude and temperature had an effect on species richness of Brachionidae. None of the variables affected species richness of Lecanidae, except habitat type, albeit not significantly. Habitat type and conductivity had an effect on species composition of the two families, whereas latitude had an effect only on species composition of Lecanidae. Species richness and composition of the two rotifer families are well documented in Thailand and no or only few additional species are expected. The limnological correlates of rotifer diversity seem to be in part comparable to and in part different from those known from temperate areas, suggesting that there may be general trends in rotifer species richness and composition across different latitudes.

Surveys on the zooplankton of the middle reach of the Po River (Northern Italy) carried out from 2008 to 2010 led to the discovery of 24 species of monogonont rotifers that are new for Italy. Among the 17 recorded genera, six are new for the Italian fauna, while three species have never been reported in the Palaearctic Region before. Temporal patterns, abundance and site of occurrence of the species are provided. Available information on the ecology and distribution of each taxon was derived from the literature and is also reported. Most of the new records are littoral and/or benthic-periphytic taxa. Results of the present study underline the still unsatisfactory status of present biogeographical knowledge on monogonont rotifers and the need for detailed taxonomic surveys in order to improve our understanding of the ecology and distributional patterns of this group.

Salinity and temperature are known to be important factors driving species richness and species composition in inland waters, but their effect and interaction are still not completely clear. In this paper we examine their interaction on species richness and species composition of planktonic rotifers in Turkey, controlling for other confounding effects. Eighty-four species of Rotifera belonging to 32 genera were recorded from eight sampling sites in Develi Plain (Middle Anatolia, Kayseri, Turkey), collecting repeated samples in different seasons (April, July, October and December 2007), and measuring water parameters (electrical conductivity, pH and temperature). Generalised Linear Models and Mixed Effect Models were used to disentangle the effect of the environmental parameters on species richness and composition. Temperature positively affected species richness as expected from previous studies. Whereas this effect was clear in the freshwater habitats (less than 1000 μS cm-1), it was not observed at all at higher salinities. Surprisingly, species richness significantly increased with salinity in subsaline waters between 1000 and 6000 μS cm-1. Species composition varied among sampling sites (accounting for 36.2% of total variation), but no other factors were found to be involved

The incidence and abundance of Monogononta rotifer species were recorded from lakes and reservoirs in the upper part of the Cambodian Mekong River basin in April and November 2010. One hundred and seven species are reported, 25 of which are new records to Cambodia and 8 taxa were unidentifiable to species level. Species richness at the regional and local scale was not significantly different between habitat types or between seasons, whether it was estimated using incidence or abundance data. Comparison of incidence data also revealed no significant difference from species richness of ponds concurrently sampled in the same region. There appeared to be a high level of diversity among sites that could not be attributed to nestedness or to the 5 environmental variables measured. Each habitat type and season offered substantially different rotifer communities, with the proportion of unshared species between sample sets ranging from 14-49%. Non-metric multidimensional scaling and PERMANOVA analyses also revealed clustering and significant differences among sample sets based on habitat type and season. Therefore, each habitat type and season contributed to the overall rotifer biodiversity. When the incidence data from this study are combined with those in previously reported studies, the overall species richness estimate for Cambodia is 403 species (95% CI = 386-432) and the number of species records has reached 306.

We surveyed Thuy Tien lake and Nhu Y river, Thua Thien Hue province, Vietnam, for rotifers from March to August 2010, and additionally in February 2012 in Thuy Tien lake. A total of 98 species-level taxa are identified, belonging to 31 genera and 21 families. Of there, 52 are first records for Vietnam, Filinia minuta (Smirnov, 1928) is new to the Oriental region and Ploesoma asiaticum n. sp. is new to science. These results increase the rotifer record for Vietnam from 122 to 174 taxa. In addition to describing the new taxon, we provide comparative illustrations including trophi scanning electron microscopy photographs of Ploesoma hudsoni (Imhof 1891).

We investigated the diversity of brachionid rotifers in Thailand. Rotifers were collected from a wide range of habitat types (294 sites, 508 samples) including canals, lakes, peat swamps, ponds, reservoirs, rice fields, rivers, swamps and temporary ponds from April 1998 to January 2004. Twenty-eight species including 11 infrasubspecific forms belonging to five genera were identified. The most frequently encountered species was Brachionus falcatus (50.7% of the sampling sites), followed by Keratella cochlearis (50%), B. angularis (49.7%), K. tropica (46.3%) and B. forficula (45.9%). Less frequently encountered species were B. caudatus, B. durgae and B. urceolaris. These species were found in low abundances and only in a single site. Two sites in the Northeast – Nong Changpeuak and Bueng Srithat – recorded the greatest richness with 15 taxa, whereas no brachionid rotifers were found in 31 sites. On average, the species richness was five taxa per sampling site. A key to the genera and species of Thai brachionid rotifers is provided.

We provide a checklist of the freshwater Rotifera recorded from Thailand, based on a review of available literature. Approximately 398 species of rotifers are recorded. The rotifer fauna of Thailand has been investigated quite comprehensively and these studies focus on four main parts of the country: the northern, north-eastern, central and southern. The number of rotifers on record is the highest in the north-eastern part (275), followed by the southern part (261), the central part (182) and the northern part (115). The majority of Thai Rotifera belongs to family Lecanidae (24.4%), Lepadellidae (11.3%), Brachionidae (11.1%), Trichocercidae (9.0%) and Flosculariidae (9.0%). The most diverse genus is Lecane followed by Trichocerca, Lepadella and Brachionus. Although most Thai rotifers are cosmopolitan, there are a number of Oriental endemics, including some strict Thai or regional endemics. Illoricate rotifers and bdelloids are understudied, while experimental and molecular approaches promise to add most to our knowledge and understanding of the role of rotifers in ecosystem functioning.