Orconectes palmeri longimanus (Faxon, 1898)

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

Orconectes palmeri longimanus (Faxon, 1898) : Western Painted Crayfish

General charateristics. Adults rarely exceed 80 mm in total length. The rostrum has a trough-like depression and well-developed lateral margins and spines. The areola is closed. In form I males, gonopods terminate in two long and slender processes that are curved caudally and the mesial process ends in a spoon-shaped tip. In females, the annulus ventralis is deep with a slit-like fossa at its anterior half. The posterior margins of the annulus ventralis are thick and inflated (Taylor & Schuster, 2004).

Life coloration. The background color is olive brown to grayish tan. Black speckling on the chelae and occasional speckling on the carapace and abdomen is present ( Figure 67 ). Fingers may have strong tints of blue to green, especially in form I males, and often have cream to yellow tips. The ventral side is cream to white.

Similar species. In Oklahoma, O. palmeri longimanus closely resembles O. difficilis and O. deanae (see O. difficilis and O. deanae sections for differences).

Distribution and habitat. Orconectes palmeri longimanus occurs in Kansas, Oklahoma, Arkansas, Texas, and Louisiana, including a majority of the western tributaries of the Mississippi River from the Arkansas River to the Gulf of Mexico (Hobbs, 1989). In Oklahoma, we have only found this species in the east central and southeastern regions of the state, with the highest populations numbers in Latimer, Pushmataha, and Choctaw counties concurring with past surveys (Creaser & Ortenburger, 1933). Our ecological niche model also indicates suitable environmental conditions slightly to the west of the counties mentioned above ( Figure 68 ). Orconectes palmeri longimanus mainly inhabits permanent streams with large rocks and boulders. This species will burrow to follow receding water levels as it is a tertiary burrower.

Life history. Form I males have been collected during the fall months, which follows similar patterns found in other crayfish in the region. This suggests that breeding likely takes place in late fall and winter and females release young late spring and early summer. Form II males and females have been collected throughout the year.

Syntopic species. Cambarus ludovicianus , Orconectes difficilis , Orconectes leptogonopodus , Orconectes menae , Orconectes saxatilis , Procambarus dupratzi , and Procambarus tenuis .

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

Additional resources. Johnson (2010); Jones & Bergey (2007).

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.