Feeding structures and their functions in adult and preadult Tigriopus californicus (Copepoda: Harpacticoida)

Tigriopus californicus uses several appendages and processes in the collection and manipulation of food. Their structure and function appear to enable the species to utilize the variety of food materials found in splashpools, including: detritus and organic flocs; superficial material on particles; faecal pellets; protists; diatoms; and small crustaceans. From light and scanning electron microscopy and video, the labrum and labium appear to be adapted for biting soft and hard food materials and holding food for trituration by the mandibles. From energy dispersive X-ray spectra, the gnathobase of the mandible is suggested to be sclerotized but not calcified or silicified. It has an array of bilobate and multilobate teeth, clusters of spinous processes, and a heavy, spine-bearing process to move food into the oesophagus. There is also a flange which articulates in a groove in the labrum which appears to provide a guide for the gnathobase as it moves vertically.