A species of amphipod.
Photos Dieter Stegemann
A different species, highly magnified. Note the young ones!
The most readily recognizable amphipod, simply because it is quite common: the hunchback amphipod Iphimedia gibba
Photos Guido Zsilavecz
Small and easily overlooked, amphipods are extremely common on our reefs. They are crustaceans, like crabs and crayfish, something which becomes clear when viewing them highly magnified. Amphipods are compressed laterally, i.e. tall but flat, unlike the isopods, which are flattened dorsally (squat and flat). Their eyes are not on stalks, as can be seen from the photos, and the first set of legs is generally form nippers. They can be found all over the reefs, feeding on detritus or filter feeding. Some, like species of the genus Caprella look somewhat like a praying mantis, holding on by their legs position towards the rear of the body, and raising their large nippers to catch planton floating by. Amphipods carry their eggs in a brood pouch below the body, and the eggs hatch directly into a small version of the adult.
Two Oceans, A guide to the marine life of Southern Africa, GM Branch, CL Griffiths, ML Branch and LE Beckley, 1994.