Pacifastacus nigrescens (Stimpson, 1857)

Wicksten, Mary K., 2012, Decapod Crustacea of the Californian and Oregonian Zoogeographic Provinces 3371, Zootaxa 3371, pp. 1-307 : 127

Pacifastacus nigrescens (Stimpson, 1857)

( Fig. 30B, K)

Astacus nigrescens Stimpson, 1857a: 87 ; 1857b: 492. — Hagen 1870: 92, pl. III, fig. 168. — Holmes 1900: 166. — Bonnot 1930: 212.

Pacifastacus nigrescens . — Riegel 1959: 44 (part, figures probably are of P. fortis ). — Hobbs 1976: 23, fig. 13b, 14d. — Kuris et al. 2007: 636.— Larson & Olden 2011: 62.

Diagnosis. Similar to P. leniusculus except rostrum concave, with prominent, acute apex; 5 or 6 lateral teeth, small spinules on postorbital ridges. Major chelae without clusters of setae, chela narrow, palm barely wider than closed fingers, fingers may be gaping. Abdominal pleura sharply triangular. Total length 78 mm.

Color in life. Blackish.

Habitat and depth. Streams near the coast. Depth not reported.

Range. Unalaska, Alaska; Fort Steilacoom , Washington, Alameda Creek , Alameda County and Coyote Creek , Santa Clara County , California ( Holmes 1900). Type locality given as San Francisco, California, but Stimpson said that he purchased his specimens in a market .

Remarks. There have been no reliable records of live P. nigrescens since those of Holmes (1900). Subsequent reports by Bonnot (1930) quoted Holmes or considered P. fortis to be a subspecies of P. nigrescens ( Riegel 1959) . Holmes' specimens probably were burned in the fire following the San Francisco earthquake in 1906, so it is impossible to double-check the identification of his material from Washington and Alaska.