Ophiura albida

Lore & Background

Ophiura albida has a central disc reaching about 1.5 centimetres in diameter and five arms up to 6 centimetres long. The disc is flattened, with the upper surface covered in small plates that are mostly brick red, except for white plates at the edge near the arms. The arms are slender, fragile, segmented, and gradually tapering, with each segment bearing three short spines that lie flat on the surface. Small pores between the plates help distinguish this species from the similar Ophiura ophiura. The underside of the disc is pale, with a central mouth fringed with teeth.

This species is found at depths down to about 200 metres, or 850 metres according to one authority, on soft substrates including coarse sand, fine sand, gravel, and muddy sand. Its range extends from Norway to the Mediterranean Sea and the Azores, and it is common around the coasts of the British Isles, where densities can reach 900 individuals per square metre.

Ophiura albida is a predator and scavenger, feeding on small invertebrates such as polychaete worms, crustaceans, and bivalve molluscs. In the Baltic Sea, it is the favourite food of the starfish Luidia sarsi, and in the Irish Sea it is eaten by the seven armed starfish Luidia ciliaris. Individuals are either male or female, with external fertilisation and planktonic larvae. It is fast-growing and not thought to live more than three years.

Reader's Guide

Ophiura albida is notable as a common brittle star in the north-eastern Atlantic and Mediterranean, often occurring in high densities on soft seabeds. Its ecological role as a predator and scavenger of small invertebrates is documented, and it serves as a key prey item for certain starfish species, such as Luidia sarsi in the Baltic Sea and Luidia ciliaris in the Irish Sea. The species is distinguished from the similar Ophiura ophiura by the presence of small pores between the plates on its arms. Its life history includes external fertilisation, planktonic larvae, and a fast growth rate, with a maximum lifespan of about three years. The species is sometimes known as the serpent's table brittle star, though the source does not explain the origin of this name.

Did You Know?

• It can be distinguished from the similar Ophiura ophiura by small pores between the plates on its arms.
• It is not thought to live for more than three years.