Aphrodita aculeata

Aphrodita aculeata
Scientific classification
Kingdom:	Animalia
Phylum:	Annelida
Clade:	Pleistoannelida
Subclass:	Errantia
Order:	Phyllodocida
Family:	Aphroditidae
Genus:	Aphrodita
Species:	A. aculeata
Binomial name
Aphrodita aculeata Linnaeus, 17581

Aphrodita aculeata, the sea mouse, is a marine polychaete worm found in the North Atlantic Ocean and the North, Baltic, and Mediterranean Seas. The sea mouse normally lies buried head-first in the sand. It has been found at depths over 3,000 m (9,800 ft).²

The name of the genus is taken from Aphrodite, the Ancient Greek goddess of love, said to be because of the worm's supposed resemblance to human female genitalia.³ The English name may derive from the resemblance to a bedraggled house mouse when washed up on shore.⁴ The specific name aculeata is the Latin for spiny.

The body of the sea mouse is covered in a dense mat of setae (hairlike structures).⁵ Adults generally fall within a size range of 10 to 20 cm (3.9 to 7.9 in).

The spines, or setae,⁵ on the scaled back of the sea mouse are some of its unique features. Normally, these have a deep red sheen, warning off predators, but when light shines on them perpendicularly, they flash green and blue, a "remarkable example of photonic engineering by a living organism". This structural coloration is a defense mechanism, giving a warning signal to potential predators. The effect is produced by many hexagonal cylinders within the spines, which "perform much more efficiently than man-made optical fibres".⁶

The sea mouse is an active predator² feeding primarily on small hermit and other crabs, and other polychaete worms, including Pectinaria and Lumbriconereis.² It has been observed consuming other polychaete worms over three times its own body length.² Feeding activity takes place at night, with the animal is partially buried in sand.²