Crowned Sea Urchin, Centrostephanus coronatus

Crowned Sea Urchin, Centrostephanus coronatus. Urchin collected from a tidal pool in the greater Los Cabos area, Baja California Sur, July 2009. Size: 10.0 cm (3.9 inches). Test: 4.0 cm (1.6 inches) x 4.0 cm (1.6 inches).

Phylogeny:  The Crowned Sea Urchin, Centrostephanus coronatus, is a member of the Diadematidae Family of Poisonous Sea Urchins. This species is also known as the Coronado’s Urchin or the Long-spined Urchin, and in Mexico as erizo Coronado.

Morphology:  In its adult form, the Crowned Sea Urchin body is black with a bluish hue at the base of the spines. These long and serrated spines are approximately two to three times as long as the diameter of the teste. The spines of the juvenile forms are banded with purplish-brown and yellow. Adults may be without banding on the spines, but typically have brown banding with lighter red or purple colors distally. They have five clusters of small spines surrounding the mouth. The test diameter can reach a maximum of 6.3 cm (2.5 inches) and their longest spines can be 12.5 cm (5.0 inches) in length, reaching about 17.5 cm (6.9 inches) combined.

Habitat and Distribution:  The Crowned Sea Urchin can be found in crevasses, coral, and under rocks during the day. They emerge at night to feed. They inhabit the intertidal zone of depths up to 125 m (410 feet). In Mexican waters the Crowned Sea Urchin is a resident of the Pacific and found in all coastal water from the Channel Islands, California to the Galapagos Islands. However, they are only found along the northwest coast of Baja following El Niño events. In 2016, a Crowned Sea Urchin was found in Monterey Bay, California.

Diet:  As nocturnal creatures, they appear at night to feed, often remaining within a few feet of their shelters. Their diet is primarily carnivorous, consuming algae, bryozoans, sponges and tunicates.

Reproduction:  Like all other sea urchins, this species is gonochoric. The reproductive spawning cycle occurs monthly, and presumed to be related to tidal rhythms or lunar cycles.

Common Misidentification:  This species is often confused with the Needle Sea Urchin, Diadema mexicanum, which has similar structure but does not have banded spines. It can also be confused with the venomous Mexican Diadema Urchin, Diadema mexicanum, which has rough spines rather than smooth spines.

Synonym:  Echinodiadema coronata.

A Word of Caution!  The Crowned Sea Urchin is not venomous, but should be handled with care because the spines are sharp, will break off in the skin, can be very painful to humans and are exceedingly difficult to remove.