Loxorhynchus grandis Stimpson, 1857

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

Loxorhynchus grandis Stimpson, 1857

( Fig. 51B, Pl. 13C)

Loxorhynchus grandis Stimpson, 1857a: 85 . — Holmes 1900: 29. — Rathbun 1904: 175. — Weymouth 1910: 31, pl. 5, fig. 14. — Schmitt 1921: text figs. 132a, b. — Rathbun 1925: 198, pls. 64, 65, text fig. 80. — Johnson & Snook 1927: 372, fig. 328. — Garth 1958: 257, pl. P, fig. 2; pl. 29. — Wicksten 1979b: 37. — Garth & Abbott 1980: 600, fig. 25.10. — Jensen 1995: 24, fig. 23. — Hendrickx 1999: 141, pl. 5D. — Hobday & Rumsey 1991: 1. — Kuris et al. 2007: 641.

Diagnosis. Rostrum slightly longer than broad, much deflexed, horns convex above, below and separated for more than half their length, with rows of hooked setae except in mature adults. Carapace rounded, inflated, covered with small, conical tubercles which may be worn in mature adults; juveniles with abundant hooked setae. Stout spine on margin of hepatic region, another just below margin. Preorbital spine large, often double pointed; postorbital spine subconical, acute. Basal antennal segment with anteroexternal spine, tubercle on outer margin; another on anterior margin at insertion of next segment. Chelipeds of adult male large, tuberculate; hand with palm inflated; female with shorter chelipeds, palm not inflated; chela slender, with narrow fingers in juveniles. Pereopods 2–5 subcylindrical, with few tubercles, propodi with grooves above, dactyls short, stout. Male carapace length 190 mm, width 145 mm; female length 114 mm, width 86 mm.

Color in life. Brown, becoming bluish-gray to chalky white in aging adults; ventral surface white. The color notes are from crabs from San Pedro and Santa Catalina I. , California. Stimpson's color notes as given by Garth (1958: 259) surely were of a dead or preserved crab.

Habitat and depth. Rocks, pilings, subtidal sand flats, sand dollar beds; lowest intertidal zone to 125 m.

Range. Cordell Bank, California to Thurloe Head, Baja California. Type locality near San Francisco , California .

Remarks. Juvenile L. grandis usually are almost impossible to detect in their natural habitat. A dense coat of bryozoans, sponges, algae, hydroids, and pieces of gorgonians or other materials covers their bodies. As the animals grow and mature, the hooked setae are lost or worn off. Mature males and females do not decorate at all.

Divers have seen adult L. grandis congregating into mating "pods" in subtidal areas near the Redondo Submarine Canyon and La Jolla. There is a fishery for them in southern California . Loxorhynchus grandis is the largest and heaviest crab found in California.