Amphipods - Amphipoda

Characteristics:

Most amphipods are constructed in an upright position, i.e. their bodies are high and slim, rather than wide and flattened like the isopods. The name means different-footed. The appendages may have different forms, in contrast to the isopods where all legs are alike. The amphipods consist of a head, a body (thorax) and a tail (abdomen), which are all quite distinct. The thorax is divided into seven visible segments and holds eight pairs of appendages. The abdomen consists of six segments and bears swimming legs and three pairs of uropods directed backward. Unlike the shrimps, the uropods of amphipods do not form a tale. Many amphipods are less than 10 mm, but the largest amphipod recorded was 28 cm.

Taxonomy:

There are 7000 registered species, 5500 of them belong to a single suborder, Gammaridea. Another suborder that are well represented along the Norwegian coast is Corophiidea, including the skeleton shrimps.