Brachionus

The following species are recognised in the genus Brachionus: • Brachionus adisi • Brachionus africanus • Brachionus ahlstromi • Brachionus amazonicus • Brachionus amsterdamensis • Brachionus angularis • Brachionus araceliae • Brachionus asplanchnoidis • Brachionus austrogenitus • Brachionus baylyi • Brachionus bennini • Brachionus bidentatus • Brachionus budapestinensis • Brachionus calyciflorus • Brachionus caudatus • Brachionus charini • Brachionus chelonis • Brachionus dichotomus • Brachionus dimidiatus • Brachionus diversicornis • Brachionus dolabratus • Brachionus donneri • Brachionus dorcas • Brachionus durgae • Brachionus elevatus • Brachionus falcatus • Brachionus fernandoi • Brachionus forficula • Brachionus gessneri • Brachionus gillardi • Brachionus havanaensis • Brachionus huangi • Brachionus ibericus • Brachionus incertus • Brachionus josefinae • Brachionus keikoa • Brachionus koreanus • Brachionus kostei • Brachionus kultrum • Brachionus leydigii • Brachionus lyratus • Brachionus macrocanthus • Brachionus manjavacas • Brachionus mirabilis • Brachionus mirus • Brachionus murphyi • Brachionus nilsoni • Brachionus novaezealandiae • Brachionus paranguensis • Brachionus pinneenaus • Brachionus plicatilis • Brachionus postcurvatus • Brachionus pseudodolabratus • Brachionus pseudonilsoni • Brachionus pterodinoides • Brachionus quadridentatus • Brachionus rotundiformis • Brachionus rubens • Brachionus satanicus • Brachionus schwoerbeli • Brachionus sericus • Brachionus sessilis • Brachionus spatiosus • Brachionus srisumonae • Brachionus urceolaris • Brachionus variabilis • Brachionus zahniseri ==Use==

Rotifers such as Brachionus calyciflorus are favored test animals in aquatic toxicology because of their sensitivity to most toxicants. They also are used as model organisms in various other biological fields e.g. due to their interesting reproductive mode in evolutionary ecology. Brachionus spp. are easily reared in large numbers and because of this are used to substitute for wild zooplankton for feeding hatchery reared larval fish. However, the composition of rotifers generally does not satisfy the nutritional requirements of fish larvae, and large amounts of research have been invested in improving the lipid, vitamin and mineral composition of rotifers to better meet the requirements of fish larvae ==Reproduction==

Brachionus species can normally reproduce sexually and asexually (cyclical parthenogenesis). Sexual reproduction (termed Mixis) is usually induced when population density increases. Mixis in Brachionus plicatilis has been shown to be induced by a density-dependent chemical cue. Transitions to obligate parthenogenesis have been described in Brachionus calyciflorus. In this species, obligate parthenogenesis can be inherited by a recessive allele, which leads to loss of sexual reproduction in homozygous offspring. In Brachionus manjavacas rotifers, offspring's survival and its cell's ability to growth and division decrease with advancing age of mother. ==Genome size==

Haploid '1C' genome sizes in Brachionus species range at least from 0.056 to 0.416 pg. ==Genome sequencing==

The complete mitochondrial genome of B. plicatilis sensu stricto NH1L has been sequenced. ==Cryptic species==

Brachionus plicatilis has been demonstrated to be a large cryptic species complex consisting of several different species. It has a worldwide diversity of at least 14 - 22 cryptic taxa. Brachionus calyciflorus also seems to be a cryptic species complex. ==References==