Stomopneustes variolaris (Lamarck, 1816)

Arachchige, Gayashan M., Jayakody, Sevvandi, Mooi, Rich & Kroh, Andreas, 2019, An annotated species list of regular echinoids from Sri Lanka with notes on some rarely seen temnopleurids, Zootaxa 4571 (1), pp. 35-57 : 40

Stomopneustes variolaris (Lamarck, 1816)

Material studied. WUSL/ER/217 (wet, with spines) from Nilwella; WUSL/ER/218 (dry, with spines) from Nilwella; WUSL/ER/219 (dry, with spines) from Hiriketiya, WUSL/ER/220 (dry, denuded) from Beruwala; CASIZ 100705, 100778, 101977, 103168 (four wet specimens, with spines), CASIZ 101939 and 102241 (two dry specimens, with spines) all from Ambalangoda.

Literature records for Sri Lanka. Walter (1885), Döderlein (1888), Herdman et al. (1904), Clark (1915), Koehler (1927), Price & Rowe (1996), Fernando (2006), Jayakody (2012), Gayashan & Jayakody (2012).

Distribution in Sri Lanka. All coasts possess suitable habitat for this species.

Recorded depth range in Sri Lanka. 0.1– 5 m (present study), 5 m (previous records) .

Habitat. Subtidal rocks, common on rocky platforms, in crevices, under boulders, and in coral reefs; well adapted to areas in which wave action is high.

Observed occurrence in this study. Eastern (Batticaloa, Panama, and Trincomalee), northwestern (Kalpitiya 1), southern (Ahangama, Hikkaduwa, Hiriketiya, Kirinda, Nilwella, Polhena, and Rakawa) and western coasts (Beruwala, Negombo) of Sri Lanka.

Remarks. The family Stomopneustidae has only one extant species. S. variolaris can be distinguished from diadematoids (with some of which it might be confused in life) found in Sri Lanka in having imperforate, noncrenulate primary tubercles, broad multiserial pore zones from the peristomial margin to the apex, large ambulacral tubercles, and a comparatively small apical system that is firmly integrated into the corona (not loosely attached by soft tissues as is usually the case in diadematoids). S. variolaris differs from camarodonts in having an open foramen (epiphyses not joined over the teeth in the Aristotle's lantern). Characteristic features of the test include the conspicuously sunken, sinuous interradial sutures and the polygeminate ambulacra with pores that are not aborally arranged in clear arcs.

In Sri Lanka, this species is widely distributed mainly from the southern to the northwestern coasts.