Procambarus liberorum (Fitzpatrick)

Map [dots indicate Ouachita National Forest collection sites]

Recognition Characters: Rostrum with gently converging margins, lacking marginal spines; acumen nearly obsolete and poorly delineated from rostrum. Areola 39.3-41.5 (average 40.2) percent of entire length of carapace; areola linear. Carapace lacking cervical spines or tubercles. Suborbital angle broadly acute to obsolete. Postorbital ridges terminating cephalically without spines or tubercles. Cephalic part of epistome rounded trapezoid, lacking cephalomedian tubercle. Antennal scale 2.05-2.67 (av. 2.31) times longer than broad, widest distal to midlength. thickened lateral part terminating cephalically in short, stout, subconical spine. Mesial margin of palm with row of 6-7 strong, spinose tubercles descreasing in size distally, two additional irregular rows of 5-6 and 3-5 more squamous tubercles medial to it. Dactyl with 2-5 small tubercles on basal fourth of mesial margin. Opposable margin of immovable finger with large tubercle in basal fourth, tiny tubercle in proximal part of gently excavated next half, and distal fourth with crowded minute denticles interrupted by small tubercle proximally. Opposable margin of dactyl deeply excavate in basal third with three small tubercles, two more tubercles on margin proximal to midlength, and distal half with band of crowded, minute denticles, broken by small tubercles near base. Ischia of third periopods only bearing hooks in males; no conspicuous prominences or bosses on coxae of periopods. Inner ramus of uropod lacking prominent spines projecting beyond distal margin. First pleopods symmetrical, strongly right-angled shoulder at base of central projection, pleopods reaching coxae of third periopods when abdomen flexed; distal extremity bearing (1) prominent, subacute, nearly setiform mesial process extending subparallel to main axis of pleopod and twice distance distally as other elements, and gently curved cephalad in distal half; (2) well developed central projection terminating distally in acute angle directed slightly caudolaterally; (3) conspicuous subrectangular (in lateral aspect) caudal process laterally compressed distally, and extending distad just beyond central projection; and (4) prominent cephalic process placed cephalomesial to central projection, extending 90 percent of length of latter and running subparallel to main axis of pleopod.

Coloration: This medium-sized crayfish possess a purplish-red to brownish dorsum that is sharply delimited from a cream-to-buff ventrolateral section of the carapace (Hobbs and Robison, 1989). It does not possess any bold markings across the carapace or chelipeds.

Size: Adults are approximately 3 to 5 inches (76-127 mm) in total length.

Habitat: This primary burrowing species lives in burrows in clay to sandy substrates in seepage areas and roadside ditches (Pflieger, 1996).

General Range: This species is a state endemic crayfish (Robison and Allen, 1995) of the Arkansas River basin and occurs from Benton and Washington counties to Pope, Scott, and Yell counties in Arkansas (Hobbs and Robison, 1988).

Comments: Hobbs and Robison (1988) presented the distribution of this endemic crayfish in Arkansas as did Robison and Allen (1995).

Six specimens of the primary burrowing crayfish Procambarus liberorum were collected during this study from four different sites in Arkansas, one in Scott County (Station 132) and three in Yell County (Stations 1-3). This wide-ranging species, while appearing rare on the ONF, is in no danger as its distributional range stretches from northern AR near Fayettville to south of Waldron and eastward to almost Morrilton, AR.

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