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The presence of the rotifer Keratella cochlearis (Gosse, 1851) is reported in El Junco Lake, a freshwater crater lake in San Cristóbal Island, Galápagos Islands. This taxon is a known species aggregate containing both eurytopic cosmopolitans as well as local and regional endemics, but also some insufficiently documented cryptic species. This record is the first of a representative of the aggregate for the rotifer fauna of the Galápagos Islands. Considering that the animal is now being recorded from the lake while earlier surveys did not, and the high dispersal capacity of many rotifers, we hypothesize that the organism recorded is one of the more widespread members of the aggregate, which colonized El Junco Lake only recently.

Abstract The presence of the rotifer species Brachionus rotundiformis from the B. plicatilis species complex in Lake Arcturo, a saline lake in the Genovesa Island of the Galápagos Islands, is here reported. This is the first record of the species for the rotifer fauna of Ecuador as well as of the species complex to the Galápagos Islands. This finding is consistent with the idea of high dispersion capacity, and of cosmopolitan distribution of this species complex. Because Genovesa Island is uninhabited, passive transport by wind currents and zoochory by migrant birds seem to emerge as the most plausible factors in this process of colonization. Integrative studies on the morphological variations, genetic, molecular, and ecological aspects are still required to further understand the process of dispersion and the ecology of this member of the B. plicatilis species complex in this remote and isolated locality, and the exact taxonomical position of the island’s population to the other members of the complex.

During the study of rotifers collected in Eastern DR Congo, we rediscovered specimens that correspond to Monostyla dorsicornuta Van Oye, 1926. This species, which we redescribe, had not been seen since it’s summary description, and lacked type material. Our analysis reveals that the animal belongs to Trichotriidae rather than to Lecane (presently considered to include Monostyla) or Lecanidae, but is nevertheless characterised by a foot structure that is remarkably convergent to that of Lecanidae, and different from all other genera of Trichotriidae.We conclude that the species and the closely related South American Macrochaetus kostei (José de Paggi, Branco & Kozlowsky-Suzuki, 2000) belong to a new genus of Trichotriidae; the two offer a rare example of African-South American vicariance in rotifers.We further provide emended diagnoses of the remaining genera of Trichotriidae, to conform these to the new information and to address some inconsistencies in these.

Following previous reports indicating a remarkable high diversity of sessile rotifers in Southeast Asian freshwaters, we report on an extensive study of the diversity of Collothecidae rotifers from fifteen freshwater habitats in Thailand. A total of 13 species, including two additional infraspecific variants, of Collothecidae are recorded, one of which is described as a new species of Collotheca. We further add taxonomic remarks on some of the taxa on record and illustrate the uncinate trophi of several representatives by scanning electron microscopic images. Finally, we provide illustrated identification keys to the Collothecidae recorded to date from Southeast Asia.

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.

The number of described species on the planet is about 1.9 million, with ca. 17,000 new species described annually, mostly from the tropics. However, taxonomy is usually described as a science in crisis, lacking manpower and funding, a politically acknowledged problem known as the Taxonomic Impediment. Using data from the Fauna Europaea database and the Zoological Record, we show that contrary to general belief, developed and heavily-studied parts of the world are important reservoirs of unknown species. In Europe, new species of multicellular terrestrial and freshwater animals are being discovered and named at an unprecedented rate: since the 1950s, more than 770 new species are on average described each year from Europe, which add to the 125,000 terrestrial and freshwater multicellular species already known in this region. There is no sign of having reached a plateau that would allow for the assessment of the magnitude of European biodiversity. More remarkably, over 60% of these new species are described by non-professional taxonomists. Amateurs are recognized as an essential part of the workforce in ecology and astronomy, but the magnitude of non-professional taxonomist contributions to alpha-taxonomy has not been fully realized until now. Our results stress the importance of developing a system that better supports and guides this formidable workforce, as we seek to overcome the Taxonomic Impediment and speed up the process of describing the planetary biodiversity before it is too late.