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While patterns in diversity and biogeography of macroscopic organisms may be fairly well-documented, this is much less the case for microscopic organisms, for which mechanisms working at entirely different scales may be relevant. Data deficiency remains a major obstacle to the study of these mechanisms, and this situation is exacerbated in regions for which accessibility is not self-evident. We here report on the Lepadellidae rotifers in zooplankton samples collected during the Boyekoli ebale Congo 2010 expedition and a subsequent visit to Yangambi, DR Congo in June 2012. The material contained eight hitherto unknown species amongst 33 Lepadellidae taxa. This remarkable result illustrates a previously unknown and largely endemic microfauna of the Congo Basin and refutes the “African anomaly” hypothesis on the purported poverty of the Central African rotifer fauna. We describe the new species, viz. Colurella asymmetrica n. sp., Lepadella hanneloreae n. sp., L. jingruae n. sp., L. weijiai n. sp., L.wilungulai n. sp., L. yangambi n. sp., Squatinella curviseta n. sp. and S. longipila n. sp., and comment on the diversity and biogeographical relationships of this fauna. Two of the new species appear to have a South American congener as their closest relative, potentially constituting two more examples of rare African-South American vicariant species-pairs in Rotifera.

Phylum Rotifera comprises about 2030 known species classified in three main groups, the marine Seisonida (3 species), the Monogononta (1570 species) and the unique, exclusively parthenogenetic Bdelloidea with 461 clonal species. Here I present an annotated checklist of the taxon, giving the global distribution of the valid species. This checklist contains over 3,000 available names at the genusand species-group level, including valid names and a non-comprehensive list of synonyms. A number of taxonomic and nomenclatural suggestions following from the review is presented. Suggestions include several new synonyms and two nomina nova: Dissotrocha kostei for Dissotrocha aculeata Koste, 1996 non Ehrenberg, 1838 (stat. nov., ex. Dissotrocha hertzogi aculeata) and Lepadella zigzag for Lepadella bractea Myers, 1934 non (Ehrenberg, 1838). This contribution also describes features of an on-line, global names database of the Rotifera, on which this checklist is based.

Following ICZN (1999) Article 79 Chapter 17 http://www.nhm.ac.uk/hosted-sites/iczn/code/), we, with the full support of the international community of rotifer researchers as expressed during subsequent international Rotifera symposia, developed a Candidate Part of the List of Available Names for species and genera of Rotifera from the start of zoological nomenclature to the year 2000.

In order to address the dearth of information on Rotifera in Vietnam, and especially on rotifers inhabiting freshwater psammon in Southeast Asia, we collected and examined twenty-five hygropsammon samples from Bau Thiem Lake, Thua Thien Hue Province, central Vietnam. A total of eighty-nine species-level rotifer taxa were identified, belonging to 21 genera and 13 families. Of these, 48 taxa (54%) are new to Vietnam, including three species, Lecane climacois Harring & Myers, 1926, Notommata cerberus (Gosse, 1886) and Trichocerca intermedia (Stenroos, 1898) that are new to the Oriental region, and three species, Lecane phapi n. sp., Lecane dorysimilis n. sp. and Trichocerca bauthiemensis n. sp. that are new to science. These, and some additional rare species are commented upon and illustrated. We estimated that the α-diversity of psammon rotifers in Bau Thiem Lake may be as high as 99 (SD=8.4; Chao2) or 115 (Jacknife2) taxa. These results indicate a high potential of rotifer diversity in the hygropsammon at Bau Thiem Lake, central Vietnam.

During our study of biodiversity of Rotifera in PR China, as model taxon of freshwater Micrometazoa, we came across several records that warrant revision regarding species of genus Mytilina Bory de St. Vincent, 1826 (Rotifera, Monogonta, Mytilinidae). In addition to this review we describe a new species encountered during examination of freshwater habitats of Inner Mongolia, P.R.China. This new species, Mytilina wangi n. sp., appears to belong to the Mytilina mucronata - ventralis complex but differs from the known taxa in the group by its domed lorica and relatively short toes. We provide an annotated checklist of the Chinese representatives of the genus and discuss the species of the M. mucronata-ventralis group. We suggest treating M. brevispina (Ehrenberg, 1830) and M. ventralis (Ehrenberg, 1830)(synonym: M. macracantha (Gosse, 1886)) as separate species-level taxa rather than as two infrasubspecific variants of the same species, and argue that Mytilina trigona var. bispinosa Wang, 1961 is a misidentified M. acanthophora Hauer, 1938 rather than an infrasubspecific variant of M. trigona (Gosse, 1851).

We review the rare Chinese rotifer Notholca dongtingensis Zhuge, Kutikova & Sudzuki, 1998, including abundant mate-rial collected during the winter months of 2009–2011 in and around the man-made Dishui Lake Southeast of Shanghai,PR China. Both an SEM study of its trophi and an account of its intraspecific variability are provided. The latter consistsin particular of a unique and previously unknown type of spine formation involving the anterolateral spines, a characterpreviously considered morphologically constant and even diagnostic in Notholca and related genera. The observations in-dicate that phenotypic plasticity invoked by a plesiomorphic triggering mechanism is not per se connected to the type orposition of structures developed, but may activate responses resulting in the formation of quite different, autapomorphic structures throughout monogonont Rotifera.

In response to a clear gap in knowledge on the biodiversity of sessile Gnesiotrocha rotifers at both global as well as regional Southeast Asian scales, we performed a study of free-living colonial and epiphytic rotifers attached to fifteen aquatic plant species in Thale Noi Lake, the first Ramsar site in Thailand. We identified 44 different taxa of sessile rotifers, including thirty-nine fixosessile species and three planktonic colonial species. This corresponds with about 40 % of the global sessile rotifer diversity, and is the highest alpha-diversity of the group ever recorded from a single lake. The record further includes a new genus, Lacinularoides n. gen., containing a single species L. coloniensis (Colledge, 1918) n. comb., which is redescribed, and several possibly new species, one of which, Ptygura thalenoiensis n. spec. is formally described here. Ptygura noodti (Koste, 1972) n. comb. is relocated from Floscularia, based on observations of living specimens of this species, formerly known only from preserved, contracted specimens from the Amazon region. In addition, ten of the species recorded are added to the fauna of the Oriental region, twenty-seven are new to Thailand.

Rotifers are obligate aquatic animals that are reputed to have particularly efficient mechanisms to survive extreme, or prolonged periods of drought, in the form of inconspicuously small resting stages, hidden between plant litter and sediment. In order to study this phenomenon, we conducted a hatching experiment on dry sediment from two billabongs in Victoria, Australia, which had been stored under dehydrated conditions for about one year. Here, we report on the diversity of rotifers that hatched during the experiment. A total of 48 species, a majority of which belong to groups of sessile rotifers, were recorded, including several new or interesting taxa. Two new taxa are described: Floscularia wallacei n. spec., and Pentatrocha gigantea n. gen., n. spec., the largest rotifer ever recorded. Ptygura ctenoida Koste & Tobias, 1990 is raised to species rank.