Rotifera is a phylum of microscopic, aquatic invertebrates. They are members of the lophotrochozoan super-phylum, along with molluscs and flatworms. The name rotifer comes from the latin “wheel” because the characteristic cilia surrounding the corona beat in a motion that resembles a wheel spinning. Rotifers are found all around the world in both freshwater and marine environments, as well as sometimes being found in damp soil.
Rotifers can be divided into two major categories- the bdelliods and the monogonots. Along with distinct morphological differences, there are also differences in the life cycles of the two taxa. Bdelloids reproduce strictly asexually, while monogonots reproduce through cyclical parthenogenesis. This is a unique cycle in which a population cycles between females that reproduce asexually and females that can bear male eggs and reproduce sexually. Also, bdelloids are capable of withstanding desiccation and entering dormancy at any point in their life cycle. Mature monogonots cannot enter dormancy, but sexually produced eggs can be dormant for many years before hatching.
Rotifers are an integral part of many marine ecosystems. They consume algae and bacteria, and are eaten by larval fish. Because of this, rotifers are of great relevance both as an indicator species in ecological studies of natural systems, and as a food source in commercial aquaculture. Due to recent advances in genetic and transcriptomic techniques, rotifers are also gaining popularity as a model organism in aging and developmental research.