Eucidaris thouarsii
# Eucidaris thouarsii

Eucidaris thouarsii, the slate pencil urchin, is a species of cidaroid sea urchins that inhabits littoral regions of the East Pacific Ocean.

## Distribution and habitat

Eucidaris thouarsii is found in the East Pacific at depths of 0–45 m (0–148 ft), ranging from Baja California to Panama, as well as Cocos Island, Clipperton Island and the Galápagos Islands. The Galápagos, Clipperton and Cocos populations are now often recognized as a separate species, E. galapagensis, instead of a subspecies of E. thouarsii.

## Diet

Like all urchins these are primarily herbivores, but feed on a wide range of invertebrates. This species has a high nutrient absorption efficiency when it comes to the coral Pocillopora damicornis, but would require a large intake to make nutrient requirements. Due to its high intake of coral, it reduces reef growth.

