Chattooga River Crayfish

Cambarus (P.) scotti

E Dactylocythere falcata: Chattooga (Hart and Hart, 1974:58)

Cambarus (Puncticambarus) scotti

Cambarus (Cambarus) montanus acuminatus.—Ortmann, 1931:110.

Cambarus extraneus.—Anonymous, 1970b:211.

Cambarus (Puncticambarus) sp.—Hart and Hart, 1974:58.

SUMMARY OF LITERATURE.—Ortmann (1931) reported this crayfish as Cambarus (C.) montanus acuminatus from the Chattooga River at Trion, Chattooga County. In order to determine what crayfish he might have had, I collected there, and among the specimens obtained, C. (P.) scotti was the only species found with which he might have confused Faxon's species. Anonymous (1970b) recorded the presence of this crayfish in Town Creek, at Route S2557, north of LaFayette, in Walker County, as Cambarus extraneus. I have examined these specimens and found them to be members of C. (P.) scotti. It was also cited by Hart and Hart (1974) as a host of Dactylocythere falcata, an entocytherid ostracod, in a stream 5.2 miles south of Summerville on U.S. Highway 27, Chattooga County.

DIAGNOSIS.—Body pigmented, eyes well developed. Rostrum tapering, acuminate, lacking marginal spines or tubercles. Areola 2.9 to 4.0 times as long as broad and constituting 30.6 to 35.5 percent of total length of carapace (40.4 to 44.9 percent of postorbital carapace length) with 7 to 10 punctations across narrowest part. Cervical and branchiostegal spines well developed: hepatic spines absent; suborbital angle strong and acute; postorbital ridges with acute spines or spiniform tubercles. Antennal scale approximately 2.8 times as long as wide, broadest almost at, or distal to, midlength. Chela with 2 well-defined rows of tubercles along mesial surface of palm (mesialmost row of 6 to 10) and with additional ones dorsolateral to rows; lateral margin of chela subcostate with moderate depression at lateral base of fixed finger; width of palm less than 1.3 times length of mesial margin; dactyl less than twice length of palm. Hook on ischium of third pereiopod of first form male overreaching basioischial articulation and opposed by tubercle on basis. First pleopod of first form male with central projection bearing subapical notch, recurved at angle of approximately 125 degrees, and constituting, if straightened, approximately 10 percent of total length of appendage; mesial process moderately inflated, directed caudally at angle only slightly less than that of central projection. Female with annulus ventralis shallowly embedded in sternum and slightly asymmetrical; first pleopod present. Carapace with dark saddle immediately anterior to cervical groove and bordering posterior margin of carapace; abdomen with paired series of L-shaped markings dorsolaterally but lacking series along bases of pleura and transverse dark bands.

HOLOTYPIC MALE, FORM I.—Body subovate, depressed (Figure 92a,j). Abdomen narrower than cephalothorax (19.1 and 21.8 mm); greatest width of carapace greater than depth at caudodorsal margin of cervical groove (21.8 and 16.4 mm). Areola 3.7 times as long as broad with 8 punctations across narrowest part, punctations small and crowded; length 35.5 percent of total length of carapace (44.9 percent of postorbital carapace length). Rostrum with strongly convergent margins lacking marginal spines or tubercles; acumen, not distinctly delimited basally, long, its slightly upturned apex almost reaching distal end of antennular peduncle; upper surface of rostrum deeply concave with thickened margins, punctations flanking mesial side of margin prominent, few in distal two-thirds, and those in proximal third coalescing horizontally, forming shallow, irregular transverse grooves. Postorbital ridge of moderate length, grooved dorsolaterally, and with acute corneous-tipped tubercle. Suborbital angle acute with distinct spine at apex. Cervical spine very strong. Carapace punctate dorsally and tuberculate laterally.

Abdomen subequal in length to carapace; pleura of moderate length, truncate ventrally, and angular caudoventrally. Cephalic section of telson with 2 spines in each caudolateral corner. Proximal podomere of uropod with distal spine on each lobe; mesial ramus of uropod with weak submedian ridge terminating in short premarginal spine. Dorsal surface of uropods and telson scabrous.

Cephalomedian lobe of epistome (Figure 92i) broadly rounded with margins elevated ventrally and with shallow submedian emargination cephalically; fovea well defined; epistomal zygoma broadly arched. Ventral surface of proximal podomere of antennule with prominent spine slightly distal to midlength. Antennal peduncle with spine on lateral surface of basis and on ventral surface of ischium; flagellum broken in holotype but reaching to fifth abdominal tergum in other specimens; antennal scale (Figure 92g) about 2.8 times as long as broad, broadest in vicinity of midlength, its mesial margin almost parallel to lateral margin at and somewhat distal to midlength; distal spine reaching level of apex of acumen. Ventral surface of ischium of third maxilliped with mesial half bearing clusters of long stiff setae and with submarginal lateral row of much smaller ones; distolateral angle subacute.

Right chela (Figure 92l) about 2.5 times as long as broad and mesial margin of palm occupying about one-third of its total length. Mesial margin of palm with row of 9 tubercles flanked dorsolaterally by second row of 7, with few additional ones between rows and laterally; most of palm conspicuously punctate. Both fingers with poorly defined longitudinal ridges dorsally and ventrally, flanked by setiferous punctations. Fixed finger weakly costate laterally; opposable margin with row of 13 tubercles (fifth from base largest) and single large tubercle on lower level at base of distal two-fifths; band of minute denticles between and distal to tubercles in distal half of finger. Opposable margin of dactyl with row of 12 tubercles (fifth from base largest), minute denticles dispersed as on fixed finger; mesial margin with row of 6 or 7 subsquamous tubercles along proximal half of finger (tubercles progressively smaller and more depressed distally) followed distally by setiferous punctations and flanked proximally by other tubercles.

Carpus of cheliped punctate with prominent furrow dorsally; mesial surface with large conical tubercle and smaller one proximal to it; ventro distal margin with massive tubercle at lateral articular knob and another submedian one. Merus sparsely punctate; dorsal surface with 2 preapical spiniform tubercles, ventromesial row of 8 progressively more spiniform ones distally, 2 large tubercles representing ventrolateral row and small spiniform one on distolateral extremity. Ventromesial margin of ischium with row of 4 tubercles.

Ischium of third pereiopod with simple hook extending proximally over basioischial articulation (Figure 92h) and opposed by tubercle on basis. Coxa of fourth pereiopod with obliquely vertically disposed caudomesial boss; that of fifth lacking boss, its ventral membrane with few scattered setae.

First pleopods (Figure 92b,d,f) with slight gap between bases and reaching coxae of third pereiopods; both terminal elements recurved caudally at angle of about 125 degrees to main shaft of appendage. Mesial process somewhat inflated, tapering, and directed caudolaterally. Central projection short, not tapering, and bearing distinct subapical notch.

ALLOTYPIC FEMALE.—Differing from holotype, except in secondary sexual characters, in following respects: cephalomedian lobe of epistome lacking cephalomedian emargination; mesial surface of palm of chela with more lateral row of 10 tubercles; opposable margin of fixed finger with 11 or 10 (left) tubercles, tubercle on lower level absent on right chela; opposable margin of dactyl with 10 or 11 (left) tubercles; merus of cheliped with ventrolateral row of 4 tubercles and ventromesial one of 9 or 8 (left). (See “Measurements.”)

Annulus ventralis (Figure 92k) about 1.7 times as broad as long, situated rather shallowly in sternum; cephalic area traversed by submedian furrow, sinus originating caudodextrally in furrow at about midlength of annulus, extending dextrally and slightly caudally; after making hairpin turn, returning to median line, there making arc crossing line and turning caudally; caudal extremity of sinus situated slightly sinistral to median line on caudal wall. Postannular sclerite subspindle shaped and about one-half as wide as annulus. First pleopod reaching cephalic margin of annulus when abdomen flexed.

MORPHOTYPIC MALE, FORM II.—Differing from holotype in following respects: all spines on carapace and chelipeds much more distinctly acute than in either holotype or allotype, and cervical spines procurved; mesial margin of palm of chela with more lateral row consisting of only 5 tubercles; fixed finger with row of 9 tubercles and that present on lower level in holotype absent; opposable margin of dactyl with row of 12 tubercles; mesial surface of carpus lacking small proximal tubercle but with bispinose major one, ventral surface with additional tubercle proximomesial to large submedian distal one; merus of cheliped with 3 tubercles in ventrolateral row and 12 in ventromesial one on left cheliped; ischium with row of 3. Hook on ischium of third pereiopod much reduced, not reaching basioischial articulation but tubercle on basis as in holotype. (See “Measurements.”)

First pleopod (Figure 92c,e) with much broader central projection disposed at angle of approximately 90 degrees, lacking even trace of subapical notch.

COLOR NOTES (Figure 89b).—(Based on holotype which somewhat encrusted, obscuring considerable details). Carapace largely pinkish tandorsally fading to cream ventrally; rostral margins and postorbital ridges vermilion; mandibular adductor region with reticulate dark pattern fusing with broad dark brown band covering and lying cephalic to cervical groove; caudal margin with narrow transverse band expanding onto caudal part of branchiostegites. First abdominal tergum dark brown, remaining ones much lighter tan with caudal edge dark reddish brown. Chela with olive suffusion dorsally, extending onto basal half of fingers; distal half of fingers pale orange cream. All tubercles bright orange to vermilion; carpus and distal half of merus with coloration similar to dorsum of carapace; remaining pereiopods mostly pale with orange splotches on articular areas.

Measurements (mm)

TYPES.—The holotypic male, form I, allotypic female, and morphotypic male, form II (numbers 146479, 146480, and 146481, respectively), are deposited in the National Museum of Natural History, Smithsonian Institution, as are the paratypes consisting of the following: 19I, 9II, 14, 31j, 24j, and 4 ovigerous . The juvenile specimens from “Etowah River, Georgia,” are excluded from the type series as are the specimens from Calhoun and Saint Clair counties, Alabama.

TYPE-LOCALITY.—Clarks Creek, 1 mile north of Holland, Chattooga County, Georgia, on State Route 100. There the creek, some 3 meters wide and as much as 0.5 meter deep, flows swiftly over a rock-littered bed. The only macroscopic vegetation in the stream was a moss growing on the rocks. Overhanging and nearby shrubs and trees included Pinus sp., Cornus florida, Alnus rugosa, and Salix nigra; a luxuriant growth of Lonicera japonica grew between and partially obscured some of the shrubs. Associated with this crayfish were Orconectes erichsonianus and Cambarus (D.) latimanus.

RANGE.—The typical form of this crayfish is confined to the Chattooga River basin in Chattooga and Walker counties, Georgia, and Cherokee County, Alabama. (See “Remarks.”)

SPECIMENS EXAMINED.—I have examined a total of 176 specimens (127 from Georgia and 49 from Alabama) from the following localities. GEORGIA. Chattooga County: (1) type-locality, 2, 1 May 1967, T. Unestam, HHH, collectors; 1I, 2, 3j, 1j, 1 ovig , 22 Apr 1968, E. T. Hall, Jr., HHH; (2) Lyerly Greek near S city limits of Lyerly on St Rte 114, 7I, 3II, 2, 6j, 3j, 1 ovig , 19 Apr 1954, J. E. Pugh, S. R. Telford, HHH; (3) Chattooga River at Summerville, 1, date and collector unknown; (4) Chappel Creek, 1 mi S of Walker Co line on US Hwy 27, 1I, 1I, 1j, 1 ovig , 22 Apr 1968, ETH, HHH; (5) Chattooga River 8 m downstream from confluence with Spring Creek, 1II. 1j, 12 Sep 1974, B. A. Caldwell; (6) Cane Creek at Welcome Hill Rd at Trion, 1II, 11 Sep 1974, BAC; (7) Perennial Spring Run 0.9 airmi WNW of Berrytown, 4II, 1 25 Jul 1974, J. McCaleb; (8) Chattooga River just NW of Trion on unnumbered rd 4I, 1II, 3, 21 Oct 1976, T. A. English. Jr., HHH. Walker County: (9) Cane Creek about 6 mi S of Lafayette, 1j, 12 Nov 1947, E. A. Lachner, P. S. Handwerk; 2I, 1II, 4, 25 Mar 1961, P. C. Holt; 2I, 2II, 2, 4j, 2j, 16 Apr 1962, J. F. Fitzpatrick, Jr., HHH; (10) Cane Creek at St Rte 151, 8I, 2II, 5, 13j, 3j, 8 Oct 1977, W. D. Kennedy, HHH; 3II, 2, 9 Oct 1977, WDK, HHH: (11) Town Creek about 3 mi N of Lafayette, 1, 1j, 6j, 14 Aug 1969, ETH: (12) Duck Creek 14 m above confluence with Chattooga Creek, 1I, 1j, 4 Sep 1974, BAC; (13) Town Creek at Rte S2557, 4j, 1j, 4 Sep 1974, BAC. County Unknown: (14) “Etowah River, Georgia,” 1j, 2j, date?, D. S. Jordan. ALABAMA. Cherokee County: (15) creek 3.0 mi N of Gaylesville on St Rte 75, 5I, 2II, 1, 15j, 10j, 1 ovig , 19 Apr 1954, JEP, SRT, HHH; (16) Terrapin Creek 5.9 mi N of Piedmont on St Rte 9, 1, 17 Sep 1969, C. R. Gilbert; (17) Terrapin Creek, “Coloma,” 1II, date and collector unknown; (18) Chattooga River, 1 mi N of Cedar Bluff, 1j, date and collector unknown. (See “Remarks.”)

VARIATIONS.—In most respects the available specimens from the Chattooga Basin in both Alabama and Georgia are remarkably uniform. Some differences occur in development of tubercles; particularly noticeable are the comparatively conspicuous ones on the lateral surface of the carapace in the larger specimens as opposed to the comparatively smooth branchiostegal and hepatic regions of the smaller individuals. The differences in the relative width of the areola are at least partially reflected in the number (7 to 10) of punctations arranged across the narrowest part. On the cheliped, the number of tubercles borne by the ischium ranges from two to four; on the dorsodistal part of the merus there are one or two tubercles and ventrally the mesial row comprises seven to 12 and the lateral one, two to four. Rarely, the small proximal tubercle is lacking on the mesial surface of the carpus, and occasionally accessory small ones occur dorsomesially and ventromesially. The row of tubercles on the mesial margin of the palm consists of six to 10, and that flanking it dorsolaterally is decidedly variable, sometimes so irregular and intermingling with other tubercles that the row is difficult to delineate. In larger, presumably older specimens, the longitudinal ridges on the fingers are not nearly so clearly defined as in the young adults. (See “Diagnosis” and “Measurements.”)

SIZE.—The largest specimen available is the allotypic female, having a carapace length of 45.0 (postorbital carapace length, 35.3) mm. The largest and smallest first form males have corresponding lengths of 41.8 (32.1) and 24.5 (18.6) mm. The corresponding lengths of the smallest ovigerous female are 30.9 (24.3) mm.

Cambarus (Puncticambarus) scotti Hobbs

Cambarus aspinosus.—Anonymous, 1970:211 [nomen nudum].

Cambarus (Puncticambarus) sp.—Hart and Hart, 1974:58.

Cambarus (Puncticambarus) scotti Hobbs, 1981:238, figs. 21b, 89b, 92, 93, 228.

TYPES.—Holotype, allotype, and morphotype, USNM 146479, 146480, 146481 (male I, female, male II); paratypes, USNM.

TYPE LOCALITY.—Clarks Creek, 1 mile (1.6 km) north of Holland, Chattooga County, Georgia, on State Route 100.

RANGE.—Chattooga River basin in Chattooga and Walker counties, Georgia, and Calhoun, Cherokee, and St. Clair counties, Alabama.

Cambarus scotti, the Chattooga River Crayfish, is a species of crayfish in the family Cambaridae. It is endemic to Alabama and Georgia. The common name refers to the Chattooga River. The original specimens were collected from Clarks Creek in Chattooga County.

The IUCN conservation status of Cambarus scotti is "LC", least concern, with no immediate threat to the species' survival. The IUCN status was reviewed in 2010.