Giant Barnacle

Austromegabalanus psittacus is a large sessile barnacle that lives in groups on hard substrates. It has a tall cone-shaped carapace composed of twelve large plates made of calcite microcrystals which are cemented together. The basal disc is firmly cemented to a hard surface. It grows to a height of 30 centimetres (12 in). There is an opening at the top with a hinged operculum through which the thoracic limbs known as "cirri" protrude. The general colour is dull white with purple and brown markings.

Austromegabalanus psittacus is a coastal species found in southern Peru, along the entire length of Chile (including offshore Juan Fernández Islands) and southern Argentina in the intertidal and littoral zone. It is recorded at depths of 0–35 m (0–115 ft), but is mostly found at 2–20 m (7–66 ft). It is most common in the Los Lagos area in Chile and is harvested for human consumption, mainly in the towns of Calbuco, Carelmapu and Puerto Montt.