Athanas polymorphus Kemp, 1915

(Fig. 8)

Athanas polymorphus Kemp 1915: 295, figs. 31, 32; Bruce & Coombes 1997: 325; Anker 2003: 294, figs. 8–13, 20e, f. Athanas near polymorphus .— Banner & Banner 1966b: 24, fig. 2.

Material examined. Indonesia. 2 males, 1 ov. female (MZB Cru 4040), southern Lombok, Lembar, prawn ponds, mud flat, in burrows in banks of brackish stream, suction pump, 0–0.2 m at low tide, leg. D.L. Rahayu et al., 14 May 2014 [LB-St5-04A]; 1 ov. female (OUMNH.ZC. 2014-10-05), same collection data [LB-St5-09]; 2 males (RMNH. CRUS.D.56737), same collection data [LB-St5-04B].

Taxonomic account. See Kemp (1915), Banner & Banner (1966b) and Anker (2003).

Habitat. Mudflats, often near mangroves or near prawn ponds; under rocks and debris or in burrows of other animals. Depth range: intertidal and shallow subtidal, probably around 0– 5 m.

Distribution. Indo-West Pacific: India, Thailand, Singapore, Indonesia (new record), Australia (Kemp 1915; Banner & Banner 1966b; Bruce & Coombes 1997; Anker 2003; present study; but see below).

Remarks. As pointed out by Anker (2003), the taxonomic status of the South-East Asian (Thailand, Singapore) and Australian materials of Athanas polymorphus remains uncertain. Therefore, the identification of the Lombok specimens as A. polymorphus is tentative; in their morphology and colour pattern (Fig. 8), they correspond well to the Singaporean specimens reported by Anker (2003). It seems that only a genetic comparison (e.g., COI barcoding gene) between the specimens from South-East Asia / Australia and fresh specimens from the type locality in northeastern India (Kemp 1915) will be able to shed some light on the former’s taxonomic identity.