Procambarus gracilis (Bundy, 1876)

Morehouse, Reid L. & Tobler, Michael, 2013, Crayfishes (Decapoda: Cambaridae) of Oklahoma: identification, distributions, and natural history, Zootaxa 3717 (2), pp. 101-157 : 137-138

Procambarus gracilis (Bundy, 1876) : Prairie Crayfish

General charateristics. Adults rarely exceed 85 mm in total length. The carapace is dome shaped, longer than the abdomen, and the areola is closed. Chelae are broad, powerful, and have a notch near the base of the dactyl, and lack tubercles except along inside margins of the dactyl and the palm. In form I males, gonopods have four short processes, with the longest process being slender, slightly curved, and tapering into a sharp tip. In females, the annulus ventralis is round in outline and has a deep fossa on either side of the midline (Pflieger, 1996).

Life coloration. The background color is reddish brown to grayish brown and nearly uniform. Chelae are similar in color but with a bluish green tint ( Figure 81 ). The ventral side is light tan to white.

Similar species. In Oklahoma, P. gracilis closely resembles other primary burrowers such as Cambarus diogenes , C. ludovicianus , Fallicambarus fodiens , and Procambarus liberorum . Procambarus gracilis can be easily differentiated from the first three species, due to its four short processes on the male gonopod as opposed to two long, curved, bladelike processes. It differs from P. liberorum by the caudal process being thinner and more narrow. In females of all listed species, the annulus ventralis of P. gracilis is unique, as it does not have a groove in its anterior margin.

Distribution and habitat. Procambarus gracilis occurs from southeastern Wisconsin and northwestern Indiana through Iowa, Illinois, northern Missouri, and into eastern Kansas, Oklahoma, and northern Texas. In Oklahoma, it is found throughout the prairie region in the north central and northeastern portions, down through the eastern side into the southeast corner of the state. Our ecological niche model confirms that the northeastern quarter of the state provides suitable environmental conditions in addition to the known distribution ( Figure 82 ). As a primary burrower, P. gracilis inhabits native grasslands and areas that were formerly native grasslands, as well roadside ditches. Notably, this species can often be found long distances away from permanent water sources.

Life history. Procambarus gracilis remains in its burrow for extended periods of time, usually emerging only during warm humid nights (Bundy, 1876). It has been noted that this species is most active right before sunset until an hour or so after sunset (Hayes, 1975). Reproduction may occur over an extended period of time as juveniles recently dispersed from the females have been found from late October through June (Page, 1985). In Missouri, form I males have been collected in traps set at the entrances of burrows in June (Pflieger, 1996). We have collected form II males and females in June from roadside ditches in the north central part of the state. Procambarus gracilis has an approximate life span of three to four years (Page, 1985).

Syntopic species. Cambarus diogenes , Fallicambarus fodiens , Procambarus acutus , and Procambarus liberorum .

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

Additional resources. Hobbs & Rewolinski (1985); Hobbs & Robison (1988); Secker (2013).

Figures

FIGURES 77 – 84. 77. Procambarus curdi 78. Potential distribution of Procambarus curdi 79. Procambarus dupratzi 80. Potential distribution of Procambarus dupratzi 81. Procambarus gracilis 82. Potential distribution of Procambarus gracilis 83. Procambarus liberorum 84. Potential distribution of Procambarus liberorum.