ASTACIDEA LATREILLE, 1802

Wicksten, Mary K., 2012, Decapod Crustacea of the Californian and Oregonian Zoogeographic Provinces 3371, Zootaxa 3371, pp. 1-307 : 123

INFRAORDER ASTACIDEA LATREILLE, 1802

Members of this infraorder commonly are called crayfishes and lobsters. Unlike spiny lobsters, these species have a spiny rostrum, large chelae on the first pereopods and characteristic reproductive structures. Only the freshwater crayfishes (families Cambaridae and Astacidae ) are found in California and Oregon, although species of the marine benthic family Nephropidae have been collected on the lower continental shelf and slope off western Mexico ( Faxon 1893, Hendrickx 1995b).

In crayfishes, the female bears a depression (the annulis ventralis) between her gonopores on the coxae of the third pereopods. Immature males have stiff gonopods on the first abdominal somite; mature males have characteristic rigid copulatory appendages at this location ( Hobbs 1976: figs. 2, 3). The female carries the eggs under the abdomen until they hatch. There are no distinct larval stages.

All species of the Astacidae found in California and Oregon are native to the area. Most live in shallow water (less than 3 m) of rivers and streams, but their depth range often is not reported. These crayfish generally live in cold waters. The male reproductive structures differ only slightly between species .

The family Cambaridae is native to the central and eastern United States, Canada, and Mexico, but has been introduced into at least some freshwater streams and ponds throughout the entire area of coverage. Members of this family inhabit rivers, streams, ponds, lakes, caves, and marshes and even damp meadows. Species of this family often have different color patterns, shape of the chelae and copulatory organs among immatures, non-reproducing males, reproducing males and females. It can be difficult if not impossible to identify members of this family to species without examining the characteristic copulatory structures of mature males. Only two species, Procambarus clarkii and Orconectes virilis , are commonly found in California and Oregon. Procambarus clarkii is widely used for aquaculture, bait or human consumption. Orconectes neglectus ( Faxon, 1885) has been found lately in the Rogue River drainage of southern Oregon, and O. rusticus ( Girard, 1852) in the John Day River of Central Oregon ( Larson & Olden 2011). Other species of the Cambaridae , such as Procambarus blandingii ( Harlan, 1830 have been imported and released from time to time ( Bonnot 1930).

Crayfishes feed on a wide variety of plants, animals and detrital material. Insects, freshwater mollusks and decaying material rich in protein are favored foods. Many crayfishes can tolerate exposure to air for some time, and may be able to crawl across damp meadows or pastures. Most species are active at night. Species of the Cambaridae may dig burrows in mud. Large fishes, raccoons, egrets and herons feed on crayfishes. Leech-like worms (family Branchiobdellidae ) and protozoans may parasitize crayfishes.

There have been few studies on the natural history of native crayfishes of California and Oregon. Hart & Clark (1989) prepared an exhaustive bibliography on many aspects of crayfish biology.