Hirsutodynomene spinosa ( Rathbun, 1911 )

Mclay, Colin L., 2001, Dynomenidae and Dromiidae (Decapoda, Brachyura) from Guam, Philippine Islands, Tonga and Samoa, Zoosystema 23 (4), pp. 807-856 : 819

Hirsutodynomene spinosa ( Rathbun, 1911)

Dynomene spinosa Rathbun, 1911: 196 , pl. 17, fig 1.

Hirsutodynomene spinosa – McLay 1999: 505, figs 3f, 5e-f, 8f, 9c, 11, 13a-b, d, 14d, 17e, 23a-g.

MATERIAL EXAMINED. — Mariana Islands. Asuncion Island, 19°40’N, 145°24’E, 1-6 m, along rock wall in holes and corals, 7. VI.1992, coll. P. Schupp, 1 24.2 × 18.0 mm ( UGI no registration number).

Guam. Piti Lagoon, 13°27’N, 144°47’E, 1.0- 2.5 m, among dead coral, 20.IX.1992, 1 20.3 × 15.9 mm ( GUM 287). — 1-2 m, under rubble, IV.1997, coll. H. T. Conley, 1 10.2 × 8.1 mm ( UGI no registration number). — Tumon Bay, 11 m, on dead finely branched coral, 1.XI.1984, coll. R. K. Kropp & J. H. Dominguez, 1 4.4 × 3.9 mm ( GUM 191B). — Orote Peninsula, southwest end, reef slope, under rock, 20-25 m, 27.II.1998, coll. L. Kirkendale & G. Paulay, 1 5.4 × 4.9 mm ( UGI no registration number) ( ZRC 2000.0745). — Orote Point, 18 m, 22. V.1998, 1 11.3 × 9.3 mm, coll. L. Kirkendale, 1 6.0 × 4.9 mm ( UGI no registration number) ( ZRC 2000.0746). — Luminao Reef, 9 m, rubble, 29. V.1998, coll. L. Kirkendale, 1 7.3 × 6.1 mm ( UGI no registration number) ( ZRC 2000.0747). — Cocos Islands, right side, 2- 8 m, rubble field, 23.IV.1999, coll. L. Kirkendale, 1 8.2 × 6.8 mm ( UGI no registration number) ( ZRC 2000.0749). — Orote Peninsula, 10-22 m, 22.XI.1999, coll. L. Kirkendale, 1 13.8 × 10.5 mm ( UGI no registration number) ( ZRC 2000.0748).

SIZE. — Maximum size for females is 32.3 × 29.4 mm, and for males, 28.7 × 21.3 mm. None of the present material exceeds these maximum sizes.

DEPTH AND HABITAT. — H. spinosa has been collected from intertidal to around 15 m, on coral. Two of the above specimens came from deeper waters at 18 m and 20- 25 m. These specimens extend the lower depth limit to around 25 m.

DISTRIBUTION. — H. spinosa is widespread in the Indo-West Pacific, from Madagascar to western Australia and Indonesia, and localities in both the North and South Pacific as far east as the Tuamotu Islands in French Polynesia.

DISCUSSION

Hirsutodynomene spinosa has been described and illustrated by McLay (1999) where a full synonymy can be found. The distinctive features of the species are: a very dense cover of setae, both long filiform setae and short setae bent at right angles near the tip; about 12 spines on the carapace surface; suborbital margin with about five short, acute spines; and a sharp spine on the inner carpal margin of the cheliped. It can be distinguished from the only other species in this genus, H. ursula (Stimpson, 1860) , which has sparse setae on the carapace, with short setae not bent at right angles; only six spines on the carapace surface; suborbital margin with only a few blunt granules; and a blunt lobe on the inner carpal margin. H. ursula is only known from the eastern Pacific.