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 (Verrill, 1867), is a member of the Diadematidae Family of Sea Urchins. The genus Centrostephanus is one of seven genera in the Diadematidae Family and there are eight species in the Centrostephanus Genus. They are also known as Coronado’s Urchin and the Long-spined Urchin, and in Mexico as Erizo Coronado. The genus name Centrostephanus comes from the Greek words meaning “center crown”. The species name coronatus is Latin and also means “crown”.

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 test. 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. This species can be confused with the Mexican Diadema Urchin, Diadema mexicanum, which has solid color spines rather than multi-color spines.

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, and to depths up to 125 m (410 feet). Crowned Sea Urchins are a subtropical to tropical Eastern Pacific species. The Crowned Sea Urchin is found in all Mexican waters of the pacific Ocean with the exception that following El Niño events they are limited to the northwest coast of the Baja Peninsula. 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 omnivorous, consuming algae, bryozoans, sponges and tunicates.

Predation: Crowned Sea Urchins are preyed upon by shore birds, crabs, fish, and sea stars.

Reproduction:  Like all other sea urchins, this species is gonochoric (male or female for life). They reproduce sexually through broadcast spawning, with external fertilization. The fertilized eggs hatch into planktonic larvae, and after several months, settle to the bottom and metamorphose into juvenile sea urchins. The reproductive spawning cycle occurs monthly, and presumed to be related to tidal rhythms or lunar cycles.

Ecosystem Interactions: The parasitic, commensal, and mutualistic relationships of Crowned Sea Urchins is poorly studied and documented. It is thought that, like other sea urchin species, crabs, fish and shrimp find protected habitat among the urchins spines in a commensal relationship.

Human Interactions: Unlike some other sea urchins, Crowned Sea Urchins are not the target of fisheries and are not widely consumed. Crowned Sea Urchins are 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. From a conservation perspective they have not been formally evaluated however they are fairly common with a wide distribution and should be considered to be of Least Concern.

Synonym:  Echinodiadema coronata.