Diogenes leptocerus Forest, 1956

Rahayu, Dwi Listyo & Osawa, Masayuki, 2012, Hermit crabs (Crustacea: Decapoda: Diogenidae) from the KUMEJIMA 2009 Expedition, Japan *, Zootaxa 3367 (1), pp. 176-190 : 183

Diogenes leptocerus Forest, 1956

( Fig. 1C )

Diogenes leptocerus Forest, 1956: 528 , figs. 8–11. — Lewinsohn, 1982a: 47. — Rahayu & Forest, 1995: 405. — Rahayu & Hortle, 2002: 616.

Material examined. 1 ovig. female 1.3 mm, Stn. Intertidal 3, Shinri Beach, 26°20ʹ57.8ʺN, 126°43ʹ33.9ʺE, 18 November 2009, intertidal ( ZRC 2011.0728); 6 males 0.8–2.4 mm, Stn. Intertidal 4, Ohara, 26°20ʹ57.8ʺN, 126°43ʹ33.9ʺE, 18 November 2009 (RUMF-ZC-1645, intertidal; 1 ovig. female 1.5 mm, 2 males 1.1 mm, Stn. Dredge 55, 26°19.442ʹN, 126°49.211ʹE, 17 November 2009, 4.7–9.5 m ( NTOU A 01221 ).

Remarks. The present specimens from Kume Island are referable to Diogenes leptocerus , and agree very well with the original description and figure of the species ( Forest 1956: 528, figs. 8–11). Rahayu & Forest (1995) and Rahayu & Hortle (2002) pointed out the difference of this species from Diogenes spinicarpus Rahayu & Forest, 1995 : the telson is truncate and has no incision on the posterior margin. In Diogenes spinicarpus , the telson has a distinct median cleft on the posterior margin, and is armed with prominent spines on the left lobe, smaller spines on the right lobe. Additional differences examined in the material studied are: the ocular peduncles of Diogenes leptocerus are subcylindrical and prominently dilated basally but less so distally, and straight on the lateral and mesial margins; while in Diogenes spinicarpus , they are dilated basally and distally, and sinuous on the lateral and mesial margins.

Distribution. Somalia, Indonesia, Vietnam and now recorded from southern Japan; intertidal to 9.5 m.

Figures

FIGURE 1. A, Dardanus brachyops Forest, 1962, female, 4.09 mm, Stn. Dredge 23; B, Diogenes holthuisi Asakura & Tachikawa, 2010, ovig. female 1.27 mm, Stn. Dredge 2; C, Diogenes leptocerus Forest, 1956, male, 2.4 mm, Stn. Intertidal 4 (right third pereopod missing); D, Diogenes pallescens, female ovig. 2.35 mm, Stn Dredge 44; E, Paguristes macrops Rahayu & Forest, 2009, male, 3.45 mm, Stn. Dredge 23 (left cheliped and right third pereopod missing); F, Pseudopaguristes laurentae Morgan & Forest, 1991, male, 2.54 mm, Stn. Dredge 78.