Black, long-spined sea urchin

Description:

It is a typical sea urchin, with extremely long, hollow spines that are mildly venomous. D. setosum can be distinguished from other species in the genus Diadema by the presence of five white spots on the animal's test, strategically located between the urchin's ambulacral grooves. In addition, a clear distinguishing characteristic of the species is the presence of a bright, orange ring around the urchin's periproctal cone, a structure commonly referred to as the urchin's "anus". A few other minor characteristics in D. setosum include bluish spots on the organism's genital plates and similar blue spots (iridophores) arranged in linear fashion along its test. Sexually mature Diadema setosum specimens average from 35 to 80 grams in weight. Adults average a size of no more than 70 millimeters in test diameter and around 40 millimeters high.

Habitat:

Is a widely-distributed species of sea urchin. Its range stretches throughout the Indo-Pacific basin, longitudinally from the Red Sea and then eastward to the Australian coast. Latitudinally, the species can be found as far north as Japan and its range extends as south as the southern tip of the African east coast. Is commonly associated with coral reefs, but is also found on sand flats and in seagrass beds. Along with the other members of the family, D. setosum is a prolific grazer. They are known to feed on a variety of algal species common on tropical coral reefs.