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, 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.