Rhabditidae

Rhabditidae is a diverse family of nematodes in the order Rhabditida (class Chromadorea, phylum Nematoda). It comprises numerous genera, including Caenorhabditis, Rhabditis, Pelodera, and Diplogaster, among others. The type genus is Rhabditis. The family is best known because it includes Caenorhabditis elegans, a widely used model organism in genetics and developmental biology.

Members are generally small and slender, with a simple body plan and a rhabditid type of esophagus. They are primarily free-living in soil, leaf litter, and decaying organic matter, where they feed on bacteria. Life cycles consist of egg and four larval stages; in many species, especially Caenorhabditis, embryos or larvae can enter a dauer stage under unfavorable conditions, allowing persistence until the environment improves.

Distribution is cosmopolitan, with species found in a wide range of habitats worldwide. They play roles in soil ecosystems as bacterivores and as prey for microinvertebrates, contributing to nutrient cycling. Some species have been isolated from freshwater sediments and decaying plant material.

Taxonomy of Rhabditidae is based on morphological features of the stoma and esophagus, reproductive structures, and other characters; molecular data have clarified relationships within the family. Rhabditidae remains an important group for comparative nematology, ecology, and biotechnology, owing to the model status of C. elegans and the availability of genetic and genomic resources.