Heterocentrotus mamillatus

Pencil sea urchin ( Heterocentrotus mammillatus )

The stylus sea urchin ( Heterocentrotus mammillatus ) lives in shallow, flow- rich waters of the coral reefs in the Red Sea and tropical Indo-Pacific from East and South Africa to Hawaii, in depths of up to ten meters.

Features

His eponymous feature are the stylus -like, thick, up to twelve inches long primary spines. The primary spines are usually brownish and may have at the ends of some white bands. There are also copies with reddish spines. The secondary spikes are flattened and short and form a mosaic on the endoskeleton that can reach a diameter of eight centimeters. The dark or whitish color secondary spines form a clear contrast to the primary spines.

Way of life

The stylus sea urchin is nocturnal and spends the day in holes, cracks and be wedged by its spines, between coral heads. At night he leaves his hiding place to microalgae, coralline algae and foraminifera graze. Pencil urchins move with their suckers on the underside and can climb well. For reproduction, the animals gather in large aggregations and release their gametes into the water.

The primary spines were formerly used for writing on slates and are now sold individually or as part of a mobile to tourists.