New records of sessile rotifers (Phylum Rotifera: Flosculariacea, Collothecacea) from Southeast Asia

Recognizing the dearth of information on the biodiversity and biogeography of Southeast Asian micrometazoa, particularly sessile rotifers, we examined two samples of submerged aquatic macrophytes (Hydrilla verticillata (L.f.) Royle and Utricularia sp.) from different sites in Cambodia. We were able to distinguish a total of 23 taxa, three of which may represent undescribed species. Two more taxa could not unequivocally be ascribed to a known species. We further comment on the distribution of Octotrocha speciosa Thorpe, which may be much less widespread than previously thought. In addition to the three possibly new species, nine are newly recorded for the Oriental region; of these, two are recorded for the second time ever. All represent new records for the fauna of Cambodia. Our results illustrate the need for more detailed and thorough taxonomic and faunistic studies on this group of poorly known organisms.