Hiatella arctica

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Hiatella arctica

Kingdom:	Animalia
Phylum:	Mollusca
Class:	Bivalvia
Order:	Myoida
Family:	Hiatellidae
Genus:	Hiatella
Species:	H. arctica

Binomial name

Hiatella arctica
(Linnaeus, 1767)

Hiatella arctica is a marine bivalve mollusc in the family Hiatellidae, found in the Arctic Ocean, and around all three main New Zealand islands and the Chatham Islands, plus Australia's Macquarie Island, from low water to depths of up to 180 m.

The thick shell is attached by thread-like hairs in holes, crevices or algal holdfasts, but often bores into soft rock and shells. The shell's shape is approximately oblong but highly irregular with no two specimens being alike. Two distinct ridges extend posteriorly from the beak on each valve. In juveniles, the ridges possess short spines that are often worn away in older specimens. The shell is sculptured with thick concentric ridges.

This species is a suspension feeder. The type of substratum selected by juveniles determines whether they become burrowers or nestlers. Those settling on hard rock will become nestlers while juveniles settling on soft rock become burrowers. The adults are able to bore into rock by mechanical abrasion using the valves of the shell. The initial penetration of the rock by juveniles may involve chemical as well as mechanical means.

Coloration is dull white with a coarse yellow-brown periostracum, with a white interior.

Length is up to about 40 mm.