Diogenes inglei McLaughlin & Clark, 1997

Rahayu, Dwi Listyo, 2022, Hermit crabs of Singapore (Crustacea: Decapoda: Anomura: Diogenidae, Paguridae), with description of two new species, Raffles Bulletin of Zoology 70, pp. 329-363 : 343

Diogenes inglei McLaughlin & Clark, 1997

( Fig. 9A, B )

Diogenes inglei McLaughlin & Clark, 1997: 34 , figs. 1, 2 (type locality: Blakang Mati , Singapore).

Material examined. 1 male, 1.1 mm ( ZRC 2021.0197 ), st. DR87, Outside Tanjong Rhu , 1°16.899′N 103°53.825′E, sand, mud, 19.5–20.7 m, 4 November 2012 ; 1 female, 1.6 mm ( ZRC 2021.0198 ), st. TB5, beside Sebarok , 1°10.5′N 103°46.512′E, rocky bottom, 63.8–64.1 m, 20 May 2014 ; 1 ovigerous female, 2.4 mm ( ZRC 2021.0199 ), st. DR208, East of Semakau , South of Sebarok, 1°11.149′N 103°47.702′E, rock, barrel sponge, 17.4–24.7 m, 24 September 2013 ; 1 female, 1.8 mm ( ZRC 2021.0200 ), no locality ; 1 male, 1.1 mm ( ZRC 2021.0201 ), 2 ovigerous females, 1.3–1.8 mm ( ZRC 2021.0201 ), st. TB113, South of Sisters’ Island, 1°12.001′N 103°50.261′E, rocky bottom, 29.3–30.5 m, 29 May 2013 ; 1 female, 1.6 mm ( ZRC 2021.0202 ), st. DR174, near Kusu Island , 1°12.202′N 103°52.178′E, red clay, dead shell, 79.6–135 m, 4 June 2013 .

Colour in life. Shield mottled with cream and light brown, with two brown spots proximally; ocular peduncle cream with red longitudinal stripes on dorsal and mesial faces; chelipeds mottled with cream and light brown, dactyl and fixed finger greenish brown; P2 and P3 cream, almost transparent, with greenish brown broad band, proximally on dactyls and carpi, subdistally and proximally on propodi, and medially and proximally on meri ( Fig. 9A, B ).

Distribution. At present known only from Singapore; 17–135 m, on rocky substrate.

Remarks. This is the first record of the species after its description and also the first discovery of male specimens. The species is very characteristic in having tapering corneas, short antennal acicles, and subequal posterior lobes of the telson. McLaughlin & Clark (1997) described this species on the basis of four female specimens collected in Singapore in 1899. The female specimens examined in this study agree with the female type series. The male specimens differ from female specimens in its unarmed pleomere 6 (armed with a spine in female specimens, including the type specimens). The male pleopods are uniramous, typical of Diogenes . One specimen was found occupying the hole of a polychaete attached to a large rock ( Fig. 9A ).

Figures

Fig. 9. A, B, Diogenes inglei McLaughlin & Clark, 1997, ovigerous female, 1.8 mm (ZRC 2021.0201); C, Diogenes pallescens Whitelegge, 1897, male, not collected, st. SD40, West P. Semakau, 1°12.389′N 103°45.24′E, 23 May 2013; D, Diogenes tumidus Rahayu & Forest, 1995, male, not collected, SW53, Seringat Kias, artificial lagoon, 1°13.630′N 103°51.218′E, 24 May 2013.