To 5 cm across the test (body)
Thick, blunt spines, reddish white with reddish brown banding, often encrusted appearing grey. Short white secondary spines.
Nocturnal, wedging itself inside crevaces during the day. Feeds on algae, bryozoans, sponges and tunicates. Lives on reefs and seagrass beds to 150ft (50m).
Reproduction in E. tribuloides seems to be sensitive to both seasonal cycles and the lunar cycle.
| Ecological Descriptors
|Co, R, S
|Veg, Spo, Bry, Tun Noct