Dardanus brachyops Forest, 1962

Rahayu, Dwi Listyo & Osawa, Masayuki, 2012, Hermit crabs (Crustacea: Decapoda: Diogenidae) from the KUMEJIMA 2009 Expedition, Japan *, Zootaxa 3367 (1), pp. 176-190 : 181

Dardanus brachyops Forest, 1962

( Fig. 1A )

Dardanus brachyops Forest, 1962: 363 . — Poupin 1996: 18, pl. 8d. —Asakura et al. 2003: 190, figs. 1–10.

Material examined. 1 female 4.1 mm, Stn. Dredge 23, 26°16.380ʹN, 126°51.502ʹE, 12 November 2009, 125– 147 m (RUMF-ZC-1611).

Remarks. Dardanus brachyops is the largest species in the genus Dardanus . Forest (1962) described this species based on three specimens with carapace length 62, 82 and 88 mm. Asakura et al. (2003) reported two specimens of 15.8 and 25.1 mm in shield length, from the Ryukyu and Ogasawara Islands. The same authors redescribed this species and discussed its affinity with D. megistos ( Herbst, 1804) , and D. lagopodes ( Forskål, 1775) .

The colouration of the ocular peduncles, chelipeds and pereopods and the spination of the chelipeds in the specimen examined are the same as described by Forest (1962) and Asakura et al. (2003). However, some differences are observed. The chelipeds are subequal in the present specimen, but the left cheliped is much larger than the right in the materials of Forest (1962) and Asakura et al. (2003). The lateral face of the dactyl of the left third pereopod is not flattened but has a narrow median longitudinal sulcus in the specimen examined, whereas it is flattened with a median longitudinal sulcus in the material of Asakura et al. (2003). This discrepancy is probably due to much smaller size of the present specimen (shield length 4.09 mm).

Colour. Shield white with few red spots. Ocular peduncles with alternately red and white bands, corneas black. Chelipeds red-orange with white spots, dactyls and fixed finger bright red. Ambulatory legs red with white spots; spots larger on meri.

Distribution. Madagascar, Chichi-jima Island in Ogasawara Islands, Ishigaki Island in Ryukyu Islands, Hawaii and French Polynesia, now recorded from Kume Island in central Ryukyus; 33– 300 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.