Marine Pill Bugs

Cymodoce coronata	Cymodoce trispinosa	Zuzara venosa

Systematics: Isopoda Family Sphaeromatidae

Distinguishing Characters:
All sphaeromatids have a compact body with a tough exoskeleton and can roll themselves up to protect the legs and soft underside. The segments of the abdomen are fused into two sections, the last with the flat uropods on the side. The three species shown here are best distinguished on the shape of the uropods and sculpture of the abdomen.

Habitat and Distribution:
Marine pill bugs live under stones and among algae in intertidal pools and subtidally throughout coastal Australia and the rest of the world. The three species shown are found only in southern Australia.

General Biology:
Marine pill bugs are scavengers and browsers, feeding on living and rotting algae and other debris on the sea floor. Most species are less than 10 mm long but some can be twice this length. They can swim but do so upside-down. They are brooders as are all isopods and females of some species develop deep cavities underneath to house the eggs and young. The family is the most commonly seen and most diverse of all isopods in southern Australia. Some of the many species are highly ornamented. Males are often more elaborately sculptured with knobs and spikes than their mates.

Discovery Centre at Museum Victoria can help you only with questions about crustaceans from southeastern Australia. It can not advise on the care of pet hermit crabs or on crustaceans from other regions.