Orconectes neglectus neglectus (Faxon, 1885)

Morehouse, Reid L. & Tobler, Michael, 2013, Crayfishes (Decapoda: Cambaridae) of Oklahoma: identification, distributions, and natural history, Zootaxa 3717 (2), pp. 101-157 : 132-133

Orconectes neglectus neglectus (Faxon, 1885) : Ringed Crayfish

General charateristics. Adults rarely exceed 100 mm in total length. The carapace is egg-shaped, nearly equal in length to the abdomen, and the areola is open. The rostrum has a trough-like depression and thick lateral margins, which abruptly narrow into a well-defined acumen. Chelae are broad and heavy, especially in form I males where there is a wide gap between the fingers when they are closed. In form I males, gonopods terminate in two slender processes and curve towards each other such that their tips nearly touch. In females, the annulus ventralis has a slitlike fossa that reaches under the anterior margin (Pflieger, 1996).

Life coloration. The background color is olive-green to brown with two dark saddles, one above the cervical groove and the other on the posterior margin of the carapace ( Figure 65 ). The lateral edges of the abdomen are lined with a dark stripe. Chelae are tipped orange followed by a distinct black ring. The ventral side is mainly white in color.

Similar species. Orconectes neglectus neglectus does not resemble any other crayfish in Oklahoma, as the chelae with orange tips followed by a distinct black ring is characteristic of this species and visible at all stages of development.

Distribution and habitat. Orconectes neglectus neglectus occurs in southwestern Missouri, northwestern Arkansas, northeastern Oklahoma, and isolated populations in central Kansas, southwestern Nebraska, northeastern Colorado, and south-central Oklahoma (Pflieger, 1996). In Oklahoma, O. neglectus neglectus is native to the Neosho River drainage in the northeast region, but has reportedly been translocated (likely by fisherman) to the Blue River located in south-central Oklahoma (Taylor et al., 2004). However, this translocation is currently debated as the Blue River harbors a variety of faunal elements (particularly fishes) otherwise found in the northeastern region of the state, despite its geographic isolation (Mayden, 1985; Mayden & Matthews, 1989). Molecular genetic studies will be requisite to determine the population status in the Blue River. Our ecological niche model indicates suitable environmental conditions are located within the native and proposed introduced areas ( Figure 66 ). Orconectes neglectus neglectus can be found in clear, rocky, and permanently flowing streams and is a tertiary burrower. Orconectes neglectus neglectus also occurs in root wads, undercut stream backs, and riffles along with other shallow areas that are free of silt and other fine sediments.

Life history. In the native range of O. neglectus neglectus , breeding occurs from September through April. Ovigerous females have been collected from April through June, with the majority being collected in April. Females with young have been collected in May. In natural habitats, life span ranges 2 to 3 years (Pflieger, 1996).

Syntopic species. Cambarus tartarus , Orconectes macrus , Orconectes meeki brevis , Orconectes nais , and Orconectes nana .

Conservation status. AFS: Currently Stable; Heritage Rank: Widespread (G5); IUCN: Least Concern; ODWC: Not Listed.

Additional resources. Evans-White et al. (2001); Gore & Bryant (1990); Imhoff et al. (2012); Larson & Magoulick (2008, 2009); Larson et al. (2009); Magoulick & DiStefano (2007); Pearl et al. (2013).

Figures

FIGURES 61 – 68. 61. Orconectes nais 62. Potential distribution of Orconectes nais 63. Orconectes nana 64. Potential distribution of Orconectes nana 65. Orconectes neglectus neglectus 66. Potential distribution of Orconectes neglectus neglectus 67. Orconectes palmeri longimanus 68. Potential distribution of Orconectes palmeri longimanus.