Some rotifers are free swimming and truly planktonic, others move by inchworming along a substrate, and some are sessile, living inside tubes or gelatinous holdfasts that are attached to a substrate. About 25 species are colonial (e.g., Sinantherina semibullata), either sessile or planktonic. Rotifers are an important part of the freshwater zooplankton, being a major foodsource and with many species also contributing to the decomposition of soil organic matter. Most species of the rotifers are cosmopolitan, but there are also some endemic species, like Cephalodella vittata to Lake Baikal.Hendrik Segers (2007). Annotated checklist of the rotifers (Phylum Rotifera), with notes on nomenclature, taxonomy Recent barcoding evidence, however, suggests that some 'cosmopolitan' species, such as Brachionus plicatilis, B. calyciflorus, Lecane bulla, among others, are actually species complexes.Dec 2011 4th Internat. Barcode of Life conference, University of Adelaide In some recent treatments, rotifers are placed with acanthocephalans in a larger clade called Syndermata.
Some rotifers are free swimming and truly planktonic others move by inchworming along a substrate and some are sessile living inside tubes or gelatinous holdfasts that are attached to a substrate About 25 species are colonial (eg Sinantherina semibullata) either sessile or planktonic Rotifers are an important part of the freshwater zooplankton being a major foodsource and with many species also contributing to the decomposition of soil organic matter Most species of the rotifers are cosmopolitan but there are also some endemic species like Cephalodella vittata to Lake BaikalHendrik Segers (2007) Annotated checklist of the rotifers (Phylum Rotifera) with notes on nomenclature taxonomy Recent barcoding evidence however suggests that some 'cosmopolitan' species such as Brachionus plicatilis B calyciflorus Lecane bulla among others are actually species complexesDec 2011 4th Internat Barcode of Life conference University of Adelaide In some recent treatments rotifers are placed with acanthocephalans in a larger clade called Syndermata