Pagurus hirsutiusculus (Dana, 1851)

Wicksten, Mary K., 2012, Decapod Crustacea of the Californian and Oregonian Zoogeographic Provinces 3371, Zootaxa 3371, pp. 1-307 : 189

Pagurus hirsutiusculus (Dana, 1851)

( Fig. 44A, B; Pl. 10B)

Bernhardus hirsutiusculus Dana, 1851: 70 ; 1852: 443, pl. I; 1855: pl. 27, fig. 3.

Pagurus hirsutiusculus .— Holmes 1900: 143 (part). — Rathbun 1904: 159 (part). — Schmitt 1921: 137, fig. 89 (part). — Johnson & Snook 1927: 334, figs. 279, 280 (part). — Makarov 1962: 171, pl. 3, fig. 4. — Wicksten 1977c: 541. — Hart 1982: 138, fig. 51 (part). — Ricketts et al. 1985: 278 (part). — Jensen 1995: 66, fig. 125. — Komai & Yakovlev 2000: 305. — Lemaitre & Castaño 2004: 78. — Kuris et al. 2007: 650.

Pagurus hirsutiusculus hirsutiusculus . — McLaughlin 1974: 175, figs. 43a–c, 44a–h. — Haig & Abbott 1980: 585, fig. 24.11. — McLaughlin et al. 1988: 430. — Mesce 1993: 95.

Diagnosis. Rostrum triangular, pointed, reaching to middle of ocular scale or beyond; much longer than lateral projections of carapace. Eyestalk stout, cornea not dilated, ocular scale pointed. Major cheliped stout, shorter than pereopods 2, 3; merus, carpus setose, with granules, spines, ridges; hand slightly convex, with many granules. Major cheliped elongated, fingers gaping in adult male. Minor cheliped setose, with granules. Pereopods 2, 3 setose, dactyls slender, about as long as propodi. Telson asymmetrical, lateral margins with notches, terminal margin with notch, teeth. Uropods asymmetrical. Carapace length to 19 mm.

Color in life. Almost black to greenish brown. Apices of minor chela tan or orange. Pereopods 2, 3 with white band on propodus, often also blue dot; dactyl whitish, striped with blue, red. Antennal flagellum banded with translucent and brown. The color notes are from crabs from Coyote Point, San Francisco Bay, California.

Habitat and depth. Often in protected areas with silt or in bays or harbors. Usually upper and middle intertidal zone, to 110 m.

Range. Eastern Hokkaido, Kuril Is., Kamchatka; Pribilof Is. to Monterey, California. Type locality Puget Sound. Records from southern California refer to Pagurus venturensis Coffin, 1957 .

Remarks. This is a common intertidal hermit crab. It usually lives in areas more protected from strong surf than P. samuelis , although both species can co-occur. It often inhabits shells of Nucella spp. In San Francisco Bay, it uses shells of gastropod species introduced from the Atlantic. Slipper shells ( Crepidula spp. ) may live inside the aperture of the shell. Mesce (1993) determined that setae on the minor chela of P. hirsutiusculus act as mechanoreceoptors and chemoreceptors during examination of gastropod shells.