Loxorhynchus crispatus Stimpson, 1857

Wicksten, Mary K., 2012, Decapod Crustacea of the Californian and Oregonian Zoogeographic Provinces 3371, Zootaxa 3371, pp. 1-307 : 221-222

Loxorhynchus crispatus Stimpson, 1857

( Fig. 51A, Pl. 13B, D)

Loxorhynchus crispatus Stimpson, 1857b: 453 , pl. 22, figs. 2–4. — Holmes 1900: 30. — Rathbun 1904: 175. — Weymouth 1910: 32, pl. 5, fig. 15. — Schmitt 1921: 213, text figs. 133a b. — Rathbun 1925: 200, pls. 66, 67. — Johnson & Snook 1927: 374, fig. 328. — Garth 1958: 260, pl. P, fig. 3, pl. 27, fig. 2; pl. 28, fig. 1. — Wicksten 1975: 35; 1977b: 122; 1978c: 217; 1979b: 37. — Garth & Abbott 1980: 601, fig. 25.11. — Ricketts et al. 1985: 168, fig. 136. — Jensen 1995: 24, fig. 22. — Hendrickx 1999: 140, pl. 5C. — Kuris et al. 2007: 641, pl. 320 E.

Diagnosis. Rostrum with more divergent horns than in L. grandis , not as deflexed, separated for more than 0.5 length of rostrum, with rows of hooked setae. Carapace somewhat triangular, more rounded in females than males, with few large tubercles: prominent tubercle on cardiac region connected by prominent ridge with tubercle on intestinal region; two tubercles on branchial regions, large tubercle, dome-like prominence on hepatic region; tubercle on anterior, posterior portion of median region; tubercle on either side of anterior median tubercle; row of small blunt tubercles on each median region extending to each rostral horn; in most individuals, all tubercles, with surrounding pile, standing out as discrete masses. Carapace densely covered with pile, with patches of hooked setae in all but oldest mature males. Preorbital spine prominent, subconical. Cheliped of adult male longer than in female, chela much more massive. In both sexes, cheliped with 3–4 upper tubercles on merus; carpus with small tubercles; fingers of chela curved. Pereopods 2–5 rather short, with hooked setae; pereopod 2 shorter than chelipeds of adult male but longer in female, merus grooved above, dactyls of all legs short, stout. Male carapace length to 196 mm, width to 140; female 105 mm, width 68 mm. (Largest male exceptionally big for this species).

Color in life. Light brown, freshly-molted individuals with dark bands on legs, fingers of chelae white, with red marks in adult male. The color notes are from crabs from Monterey Bay and San Pedro, California.

Habitat and depth. Rocks, jetties, pilings, kelp beds, rocky reefs, worm tube beds; extreme low tidal zone to 200 m.

Range. Orford Reef, Oregon to Natividad I., Baja California , but rarely found north of San Francisco , California . Type locality San Miguel I., California.

Remarks. The moss crab Loxorhynchus crispatus is the most heavily decorated crab of California or Oregon. Juveniles camouflage themselves with pieces of algae, bryozoans, sponges, ascidians, hydroids, or whatever is flexible and available (in one instance in Carmel Bay, with leaves from a tree). The decorating behavior remains in adult females but is lost in mature males, which at most decorate the rostrum. Large adults of both sexes also may bear barnacles, tunicates, tubeworms and other organisms that settle on them in situ.