monogonont

Monogononta is a class within the phylum Rotifera, comprising the majority of rotifer species. Members are found in a wide range of aquatic environments, including freshwater, brackish waters, and some marine habitats. They are small, often less than a millimeter in length, and feed using a ciliated anterior wheel or corona that creates currents to trap food particles, which are processed by a muscular mastax.

A typical skeletal and reproductive pattern distinguishes monogononts. Most possess a single ovary and a single genital opening, with body plans that include a trunk and sometimes a posterior foot, and in many species a protective external shell or lorica. Resting stages such as diapause eggs can form to endure unfavorable conditions.

Reproduction in Monogononta is commonly cyclical parthenogenesis. Under favorable conditions, females reproduce asexually, producing diploid eggs that develop into daughters. When environmental conditions deteriorate, some populations switch to sexual reproduction, producing haploid eggs that become males if unfertilized; fertilized eggs develop into resting eggs capable of withstanding hardship and later hatching into females. This mix of asexual and sexual modes contributes to the group’s resilience and genetic diversity.

Ecology and significance: Monogononts are important components of aquatic food webs, acting as grazers of microalgae and as prey for small invertebrates and fish larvae. Because of their rapid life cycles and sensitivity to environmental changes, they are frequently used in ecological monitoring and ecotoxicology studies. Taxonomically diverse, they include numerous genera and species with varying degrees of morphological specialization.