Common Knobbed Sea Star

Penteracaster mammillatus

Habitat & Distribution: reef-associated, depths 4 - 25 m, Indian Ocean

Diet: Encrusting algae, small invertebrates, coral polyp and detritus/organic material

Size: Up to 30 cm

Lifespan: Up to 10 years

Description

It has a hard, hefty body with tapering arms that look like triangles. Its base color is often darker, like blue or green, and the spines tend to be a brighter color like orange or white. Its tube feet underneath are bright pink.

Behavior

This sea star will suck and digest small encrusting life forms or detritus on corals, rocks, sponges, etc.

Reproduction

They reproduce both sexually through broadcast spawning and asexually via regeneration. 

Communication & Perception

They communicate and interact with their environment by way of chemical cues and physical contact. At the end of each arm, the sea star has a rudimentary compound eye that is able to tell dark from light, and sense when a large object is placed in front of it.

Predator

Pufferfish, parrotfish