Arbaciella

Overview

Arbaciella elegans is a small sea urchin that has historically been classified as a distinct species within the family Arbaciidae. Recent scientific research, however, suggests that this organism is actually the juvenile form of the common black sea urchin, Arbacia lixula, rather than a separate species.

Appearance

This urchin is characterized by its very small size, typically reaching a maximum diameter of about 7.5 mm. Its body is generally light beige in color, marked with reddish spots and rings. It features a limited number of primary spines located primarily around the periphery, or ambitus, of the test. These spines are notably thick, short, and have a distinct triangular cross-section with blunt tips.

Distribution & habitat

While historically reported across various regions including the Mediterranean and parts of the Atlantic, current consensus indicates that many of these sightings were misidentifications of Arbacia lixula juveniles. The species is considered to have a more restricted distribution, with confirmed presence in parts of West Africa. It typically inhabits the continental shelf in cryptic, hidden environments, often found on sedimentary or coralligenous seafloors.