Tripneustes gratilla gratilla (Linnaeus, 1758)

Material studied. WUSL/ER/276 (wet, denuded) from Silavathurai; WUSL/ER/277 (wet, with spines) and WUSL/ER/278 (wet, denuded) from Hiriketiya; WUSL/ER/279 (dry, denuded) from Polhena; WUSL/ER/280 (dry, denuded) from Hikkaduwa; WUSL/ER/281 (dry, denuded) from Ahangama.

Literature records for Sri Lanka. Walter (1885), Döderlein (1888), Clark (1915), Koehler (1927), Fernando (2006), Jayakody (2012).

Distribution in Sri Lanka. Southern, northern, and northwestern coasts of Sri Lanka.

Recorded depth range in Sri Lanka. 0.1– 12 m (present study).

Habitat. Mainly found on sandy bottoms among seagrass beds.

Observed occurrence in this study. Northern (Silavathurai), southern (Polhena, Hikkaduwa, Hiriketiya, Kirinda, Godawaya, Ahangama), and western coasts (Negombo) of Sri Lanka.

Remarks. Tripneustes gratilla gratilla is one of the most common shallow water species found among the seagrass beds of the southern coast of Sri Lanka. The colour of the primary spines varies from orange to white.