Copepods are small aquatic crustaceans with a body size mostly in millimeter range, which show a incredible variability of general body shape and morphology. In their basic groundpattern they show the following characters: the head and the first thoracic somite are fused to form a cephalothorax. The first thoracopods are functionally connected as maxillipeds with the mouthparts. The remaining thoracic somites form a peraeon with 6 pairs of peraeopods. The 3 subsequent abdominal somites carry no appendages. The following body part, the telson, carries terminally the paired furcal rami which are armed with 7 setae each. The anus opens dorsally and is covered by an analoperculum. The genital opening or openings are located ventrally on the 7th thoracic somite.
Appendages: the antennules are uniramous and comprise up to 27 segments. The antennae, mandible and maxillule are biramous whereas the maxilla and maxillipeds are uniramous without exopod. The pairs of peraeopods 1-5 are developed as biramous swimming legs and both members of a pair of legs are functionally coupled by a rigid intercoxal sclerite. The 6th pair of peraeopods is reduced and included into the genital apparatus.

Move the mouse over the appendages of the copepod on the right to see details!