Palaemon macrodactylus (Rathbun, 1902)

Wicksten, Mary K., 2012, Decapod Crustacea of the Californian and Oregonian Zoogeographic Provinces 3371, Zootaxa 3371, pp. 1-307 : 53

Palaemon macrodactylus (Rathbun, 1902)

( Fig. 12A, Pl. 1D)

Leander macrodactylus Rathbun, 1902b: 52 , fig. 24. Leander macrodactyla . — Kobyakova 1937: 99. Palaemon macrodactylus . — Newman 1963: 119, fig. 1. — Kobyakova 1967: 238.— Chace & Abbott 1980: 570, fig. 23.1. —

Standing 1981: 777. — Wicksten 1989a: 14. — Jensen 1995: 52, fig. 95. — Kuris et al. 2007: 638, pl. 316 E. — D'

Udekem d'Acoz et al. 2005: 95, Figs. 1, 5 d, j, n, s, 6.

Diagnosis. Similar to P. ritteri but much larger. Rostrum as long as scaphocerite, with 9–15 dorsal teeth, bare space near apex, 3–4 ventral teeth including subapical tooth. Carapace with antennal, branchiostegal teeth. First segment of antennular peduncle broad, flattened, with prominent distolateral spine, small proximal spine. Basicerite with distolateral tooth, carpocerite shorter than antennular peduncle. Third maxilliped slender, setose. Pereopod 1 slender, chelate. Pereopod 2 longer than pereopod 1, carpus about as long as merus, carpus nearly as long as entire chela. Pereopods 3–5 slender, with simple dactyls. Abdominal pleura 1–4 rounded, fifth with distolateral point, sixth with distolateral, ventrolateral points. Telson shorter than uropods, with 2 pairs dorsolateral spines. Total length 58 mm. Detailed illustrations are given by D'Udekem d'Acoz et al. (2005: figs. 1, 5, 6).

Color in life. Translucent brown to greenish or olive, may have oblique transverse stripes on carapace.

Habitat and depth. Docks, pilings, shores of bays, intertidal zone to 1 m.

Range. Native to coast of Korea, China and Japan. Introduced into Australia, San Francisco Bay , Moss Landing , Elkhorn Slough, Malibu Lagoon, Long Beach Harbor and San Diego county, California; Spain, England , southern North Sea in Belgium and the Netherlands . Type locality Aomiri , Rikuoku, Japan .

Remarks. This large shrimp can be common among rocks and cobble along the coast of San Francisco Bay. Although it can inhabit estuarine areas, it also occurs in normal ocean salinities (35 ppt) in San Francisco Bay.