CRANGONYCTIDAE Bousfield, 1973

Graening, G. O., Rogers, D. Christopher, Holsinger, John R., Barr, Cheryl & Bottorff, Richard, 2012, Checklist of Inland Aquatic Amphipoda (Crustacea: Malacostraca) of California, Zootaxa 3544, pp. 1-27 : 8

CRANGONYCTIDAE Bousfield, 1973

Crangonyx floridanus Bousfield, 1963 ; Florida Amphipod (stenohaline, exotic)

Records: Contra Costa, Sacramento, San Joaquin, and Solano Co’s. In the Delta, including Brown’s Island, Donlon Island, Lindsey Slough, Mandeville Island, Mildred R., Old R., Sand Mound Slough, Sherman Island, Sherman Lake, Venice Cut, and West Canal at Clifton Court Forebay intake ( Toft 2000; Toft et al. 2002; CDWR database). Contra Costa Co. Simas Cr., Wildcat Cr. El Dorado Co. Hangtown Cr., 29 Oct. 2009. Stanislaus Co. Tuolumne R., 2002, N. Hume.

Comments: This invasive species is endemic to swamps, ponds, and caves in the southern and eastern USA, naturally ranging as far west as central Kansas ( Zhang and Holsinger 2003). It has been introduced, possibly via aquarium and water garden plants or ship ballast, to California, Colorado, Oregon, Washington, and Japan ( Zhang 1997; Toft et al. 2002; Zhang and Holsinger 2003; Sytsma et al. 2004).

Crangonyx pseudogracilis Bousfield, 1958 ; Northern River Amphipod (stenohaline, exotic)

Records: San Luis Obispo Co. Stenner Cr. and its tributary Brizzolara Cr., from several locations, in 2002-2003 ( Bottorff et al. 2003).

Comments: Native to the central USA and southern Canada between the Great Plains and the Appalachian Mountains, C. pseudogracilis has been introduced to the United Kingdom, Ireland, and the Netherlands in Europe, probably via ballast water ( Bousfield 1958; Zhang and Holsinger 2003). In North America, this species has been introduced to Arizona, California, Nevada, and the Columbia R. ( Zhang 1997; Zhang and Holsinger 2003; Bottorff et al. 2003; Sytsma et al. 2004). Zhang (1997) reports specimens taken in 1955 from the Truckee R. (Washoe and Storey Co’s, Nevada).

Crangonyx richmondensis Ellis, 1940 ; Ellis’ Bog Amphipod (stenohaline)

Records: Sonoma Co. pond on Privot farm, 25 specimens, 1984, L. Eng, CA Dept. of Fish and Game ( Zhang 1997; Zhang and Holsinger 2003).

Comments: C. richmondensis sensu lato is the most widely distributed of its congenerics, found in many lentic and lotic habitats, and occasionally, in caves. It is distributed primarily in three regions—the Pacific Northwest (northern California to southern Alaska), the Great Lakes area (Minnesota to Newfoundland), and Atlantic Coastal Plain (Maine to Florida). Bousfield (1958) designated the subspecies occidentalis, laurentianus, and richmondensis for each of these regions, respectively, but Zhang and Holsinger (2003) report that intraspecific variation renders these subspecific designations invalid.