Ten-Lined Urchin

Eucidaris metularia

Eucidaris metularia is a species of sea urchin characterized by its robust and somewhat flattened test, which can reach up to 3 cm in diameter. This urchin has a sparse covering of stout, truncated primary spines that are distinctively banded, with smaller, flattened secondary spines surrounding them. It is found in the shallow regions of the Indo-Pacific Ocean, inhabiting areas such as the Red Sea, East Africa, Madagascar, the Seychelles, Aldabra, Chagos, Fiji, Hawaii, Japan, and northern Australia. Typically, it resides in rocky back-reef lagoons and among seagrasses, often at depths ranging from 0 to 500 metres, although most occurrences are shallower than 40 metres. Feeding primarily on algae, including coralline algae, Eucidaris metularia also scavenges for organic detritus, sponges, and bryozoans. Its spines provide both protection from predators and assistance in moving across the seabed, often camouflaged by bits of adhering seaweed. This sea urchin reproduces through external fertilization, releasing gametes into the sea, where planktonic larvae develop before settling on the seabed to metamorphose into juveniles. Encounters with the ten-lined urchin during dives can be common, especially in its preferred habitats. Divers may observe its distinctive spines and the way it blends into its surroundings, making it an interesting find in shallow waters. The species has not been evaluated for conservation status, indicating a lack of specific threats identified at this time.