Daphnia pulex

**Definition:** A freshwater water flea with distinctly stout middle pecten of the postabdominal claw and small symmetrical polygonal markings on the rostrum. D. pulex and several closely related species such as D. pulicaria belong to what is sometimes known as D. pulex complex and can hybridize. Daphnia pulex is found ubiquitously and is often the most common species in ephemeral pools and is a model system for various ecological, ecotoxicological and biomedical studies.

**Tree numbers:** - B01.050.500.131.365.150.200.750

**Synonyms:** - Common Water Flea