A solitary sea squirt with a tough, deeply wrinkled tunic that collects sand, shell fragments and algae until the animal is indistinguishable from the rubble around it. Only the two short siphons at the top give it away, and even those close down when a diver comes near. Height reaches about 7 cm (3 in).
Camouflage by accumulation is the usual strategy in this genus, and it works: most divers have swum over hundreds of these without registering one. The tunic is thick and leathery enough that almost nothing eats an adult, and members of the family are themselves eaten in several countries - the piure sold in Chilean markets is a Pyura, prised off rocks and served raw. What looks like a lump of rubble is therefore an animal with a shell of its own making, a pump inside it, and a food industry built on its relatives.
- tough wrinkled tunic, usually encrusted with sand and debris
- two short siphons close together at the top
- looks like a lump of rock until the siphons are seen
- height up to 7 cm
