Identification: Ringed Crayfish range in color from olive-green to reddish-tan. The tips of their claws (chelae) are bright orange and are preceded by prominent black or brown annular bands. Chelae are broad and robust, especially in males, with a wide gap between each finger when they are closed (Pflieger 1996). Its rostrum contains a trough-like central depression, which usually has a low ridge positioned along its midline. Male gonopods terminate in two elongate, slightly curved, processes with tips that are separated by a narrow space (Pflieger 1996; Wagner et al. 2010). Two subspecies of Faxonius neglectus are recognized; Faxonius neglectus neglectus (the Ringed Crayfish) and Faxonius neglectus chaenodactylus (the Gap Ringed Crayfish) (Williams 1952; Hobbs 1989; Taylor et al. 2007). Detailed illustrations of morphological features characteristic to each subspecies are given in Williams (1954a) and Pflieger (1996).
The nominate subspecies, F. n. neglectus, is typically light green, tan, or yellow in coloration, with conspicuous reddish markings on its ridges and tubercles (Williams 1954a). Black annular rings posterior to tips of chelae are almost always present in F. n. neglectus (Williams 1954a; Pflieger 1996). Two dark saddle-marks are found on its dorsal surface, one just forward of the cervical groove and the other at the posterior margin of the carapace. A thin, nearly black stripe lays lengthwise along each lateral margin of the abdomen, and the posterior margin of each abdominal segment is trimmed in bright red (Pflieger 1996). The chelae of F. n. neglectus are heavy, and when closed, its finger gape is less than 25 percent of the width of its palm. Its rostrum is prominent, has poorly defined lateral spines, and nearly parallel sides (Williams 1954a).
The subspecies F. n. chaenodactylus is typically dark green, yellowish-green, or flesh-pink in color (Williams 1954a). A broad brownish stripe runs along each lateral margin of the abdomen and converges posteriorly to form a characteristic V-shaped pattern. Chelae have broad, brown rings near their tips, followed by pale yellow color towards their bases (Pflieger 1996). The chelae of F. n. chaenodactylus have more slender claws, with a finger gape that is wider than 25 percent of the width of palm. Additionally, the rostrum of F. n. chaenodactylus is smaller and shorter than that of F. n. neglectus (Williams 1952; Wagner et al. 2010).
References: (click for full references)
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Hobbs, H.H., Jr. 1989. An illustrated checklist of the American crayfishes (Decapoda: Astacidae, Cambaridae, and Parastacidae). Smithsonian Contributions to Zoology 480:1-236.
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