Portunidae Rafinesque, 1815

Wicksten, Mary K., 2012, Decapod Crustacea of the Californian and Oregonian Zoogeographic Provinces 3371, Zootaxa 3371, pp. 1-307 : 234

Family Portunidae Rafinesque, 1815

The swimming crabs are most abundant in warm temperate to tropical seas. Three native species, only one of them common, may be found in California. The Atlantic green crab Carcinus maenas has been introduced into bays. Individuals or parts of the exoskeleton of Callinectes sapidus Rathbun, 1896 ; the Atlantic blue crab, have been reported in San Francisco and Half Moon Bays, California, and rarely elsewhere. This crab has been shipped to fish markets alive from the eastern coast and Gulf of Mexico of the U.S.A. There is no evidence that this estuarine species is established anywhere on the west coast of North America. Kuris et al. (2007, pl. 319 M) provided an illustration. There are two old records of Callinectes bellicosus ( Stimpson, 1859) from San Diego and Point Loma ( Garth & Stephenson 1966: 47), but this crab generally is found from San Quintin Bay, Baja California south to the southern Gulf of California, Mexico.

Swimming crabs usually have a carapace that is wider than long. There is no rostrum. The carapace bears lateral teeth, the posterior of which may be considerably larger than the anterior teeth. The orbit is complete. The first antennae fold obliquely or transversely. The chelae are toothed; the cheliped bears spines. As the common name suggests, most swimming crabs can swim strongly by means of paddle-like dactyls of the fifth pereopods. Common near shore species can dig rapidly into sand.

Except for Carcinus maenas , species of the Portunidae of the eastern Pacific have been discussed in detail in the work by Garth &Stephenson (1966). The descriptions and key given here are in large part derived from the 1966 work, which contains further information on anatomy, ranges and classification.