Cambarus acanthura

Cambarus (Lacunicambarus) acanthura

Cambarus (Lacunicambarus) species J.—Hobbs, 1969a:110, 146*, 148, fig. 11.

Cambarus diogenes subsp.—Anonymous, 1970b:221*.—Hart and Hart, 1974:44*, 134*.

Cambarus d. diogenes.—Bouchard, 1972:35.

Cambarus (Lacunicambarus) sp.—Bouchard and Hobbs, 1976: 13.

The above references to Georgia are indicated by asterisks.

REVIEW OF LITERATURE.—This crayfish was first mentioned by Hobbs (1969a) in his summary of the distribution and phylogeny of the genus Cambarus, in which he indicated its presence in the Coosa Basin in Alabama and Georgia. The Georgia records cited by Anonymous (1970b) and Hart and Hart (1974) were based on my tentative identifications. The former cited the crayfish from the Little Tallapoosa River at U.S. Highway 78, Carroll County, and the latter from two localities: 1.8 miles north of Calhoun on State Route 41, Gordon County, where it served as host to the entocytherid ostracod, Cymocythere cyma (Hobbs and Walton, 1960a), and 9.7 miles north of Rome, Floyd County, as host to Uncinocythere simondsi. Its association with C. (D.) cymatilis was pointed out by Bouchard (1972) and with C. (J.) nodosus by Bouchard and Hobbs (1976).

DIAGNOSIS.—Rostrum without marginal spines or tubercles and lacking median carina. Carapace without cervical spine or prominent tubercle. Areola 28 to about 75 times as long as broad, constituting, in adults, 36.9 to 43.9 (average 39.5) percent of entire length of carapace (43.5 to 51.0, average 46.4, percent of postorbital carapace length), and never with more than 2 punctations in narrowest part. Antennal scale little more than 2.5 times as long as wide, widest proximal to midlength. Palm of chela with several rows of tubercles, mesialmost row consisting of 6 to 9. Mesial ramus of uropod with prominent distomedian spine overreaching distal margin. First pleopod slightly convex cephalically, terminating in short, nontapering, distally rounded central projection and comparatively slender mesial process, both directed caudally at angle only slightly greater than 90 degrees. Female with annulus ventralis subcircular in outline and rather deeply embedded in sternum; first pleopod reaching about midlength of annulus.

HOLOTYPIC MALE, FORM I.—Body subovate, compressed (Figure 85a,j). Abdomen narrower than cephalothorax (12.7 and 16.4 mm); maximum width of carapace greater than depth at caudodorsal margin of cervical groove (16.4 and 14.5 mm). Areola about 49 times as long as broad with 2 punctations in narrowest part; length 41.6 percent of total length of carapace (48.5 percent of postorbital carapace length). Rostrum with convergent thickened margins; acumen not distinctly delimited basally, its upturned tip reaching base of ultimate podomere of antennular peduncle; upper surface of rostrum concave with relatively few punctations other than usual submarginal ones. Subrostral ridge weak but evident in dorsal aspect along basal two-thirds of rostrum. Postorbital ridge rather prominent, grooved dorsolaterally, and ending cephalically without spine or corneous tubercle. Suborbital angle very prominent although rounded apically; branchiostegal spine absent. Cervical spine represented by very small tubercle only slightly larger than granules on branchiostegites and in hepatic region. Carapace punctate dorsally and granulate laterally. Abdomen subequal in length to carapace, pleura (Figure 86a) short, subtruncate, rounded caudoventrally. Cephalic section of telson with 2 spines in each caudolateral corner. Proximal podomere of uropod (Figure 86b) with caudal spine on mesial lobe; mesial ramus of uropod with prominent median rib ending distally in strong distomedian spine overreaching rounded margin of ramus, laterodistal spine of ramus also strong.

Cephalomedian lobe of epistome (Figure 85g) narrow and subtriangular with margins somewhat thickened, ventral surface arched ventrally; main body with small, shallow fovea; epistomal zygoma arched. Ventral surface of proximal podomere of antennular peduncle with small acute spine at base of distal third. Antennal peduncle without spines; flagellum reaching fourth abdominal tergum; antennal scale (Figure 85i) 2.7 times as long as broad, broadest proximal to midlength, mesial border forming simple arc; distal spine strong, reaching distal extremity of antennular peduncle. Mesial half of ventral surface of ischium of third maxilliped studded with irregular rows of long, stiff setae; submarginal lateral row on podomere consisting of much smaller flexible ones; distolateral angle not acute.

Right chela (Figure 85l) slightly more than twice as long as broad, and mesial margin of palm occupying about two-fifths of its length. Mesial surface of palm with 2 clearly defined rows of tubercles and 1 or 2 additional less regular rows, mesialmost composed of 8 (left with 9) tubercles, and adjacent one of 6 (left with 7): dorsomesial half of palm with additional tubercles arranged sublinearly, and dorsolateral half punctate, punctations deep and larger in vicinity of dorsolateral base of fixed finger: lateral surface of palm and fixed finger not costate; ventral surface of palm punctate, with small corneous tubercle on articular rim opposite base of dactyl. Both fingers of chela with well defined submedian tubercle dorsally and ventrally; opposable margin of fixed finger with row of 6 tubercles (fourth from base largest) along proximal two-thirds of finger and additional large one on lower level at base of distal fourth. Opposable margin of dactyl with row of 7 tubercles (first and fifth from base larger) along proximal four-fifths; single row of minute denticles extending distally from fourth tubercle on both fingers, interrupted by more distal members of tubercular rows; mesial surface of dactyl with tubercles basally giving way to punctations distally.

Carpus of cheliped with distinct furrow dorsally; dorsomesial surface with row of 6 (left with more irregular row of 9) low, rounded tubercles; dorsolateral surface punctate; mesial surface with 1 large spiniform tubercle and 6 or 8 additional ones; ventral surface with usual 2 distal marginal tubercles and small more proximal one mesially. Merus with 2 premarginal tubercles dorsally, ventrolateral row of 4 (left with 5) tubercles, and ventromesial one of 9 (left with 10); podomere otherwise smooth to sparsely punctate. Mesial margin of ischium with row of 3 (left with 4) small tubercles. Ischium of third pereiopod with simple hook extending proximally over basioischial articulation (Figure 85h), not opposed by tubercle on basis. Coxa of fourth pereiopod with vertically disposed caudomesial boss; that of fifth pereiopod lacking boss, its ventral membrane bearing oblique row of small sclerites armed with stiff setae.

First pleopod (Figure 85b,d,f) reaching coxa of third pereiopod, slightly arched cephalically; central projection short, not tapering, lacking subapical notch, and broadly rounded apically; mesial process somewhat finger-like, tapering, and directed essentially caudolaterally, but arched laterally with tip directed caudally. Both terminal elements bent caudally at angle slightly greater than 90 degrees; caudal knob absent.

ALLOTYPIC FEMALE.—Excluding secondary sexual characters, differing from holotype in following respects: rostrum with more nearly subparallel, nonthickened margins contracted sharply at base of acumen; apex of latter not quite reaching base of ultimate podomere of antennular peduncle; spine on antennal scale reaching only to base of ultimate podomere of antennular peduncle; caudal section of telson (Figure 86c) with subsymmetrically arranged pair of marginal spines; opposable margin of dactyl of chela with row of 8 tubercles; dorsomesial surface of carpus of cheliped with row of 7 tubercles; remaining podomeres with numbers and arrangements of tubercles within range of variation exhibited by holotype. (See “Measurements.”)

Annulus ventralis (Figure 85k) deeply embedded in V-shaped sternum, subcircular in outline, with narrow median longitudinal furrow in cephalic half ending in central depression; tongue extending caudosinistrally across caudal side of depression, disappearing beneath thickened caudosinistral wall; sinus S-shaped and tilted sinistrally at almost 90 degrees, ending on caudal wall slightly dextral to median line. Postannular sclerite, partly hidden by caudomesial part of annulus, ovate, almost twice as broad as long, and approximately four-fifths as wide as annulus. First pleopod reaching midlength of annulus when abdomen flexed.

MORPHOTYPIC MALE, FORM II.—In addition to usual contrast in secondary sexual characters, differing from holotype in following respects; rostrum angular at base of acumen; apex of latter and spine on antennal scale both reaching base of ultimate podomere of antennular peduncle; branchiostegal spine represented by very small tubercle; median spine on mesial ramus of uropod more acute, and caudal section of telson with pair of marginal spines similar to those in allotype; mesial margin of palm of left chela with row of 7 tubercles; merus of chela with ventrolateral and ventromesial rows of tubercles consisting of 3 and 11 on right chela and 4 and 12 on left, respectively; mesial margin of ischium with only 2 minute tubercles. (See “Measurements.”)

First pleopod (Figure 85c,e) with juvenile oblique suture in basal half; central projection noncorneous and not bent quite so strongly caudally; neither it nor mesial process so long as in holotype.

COLOR NOTES (Figure 84a).—Carapace dark reddish brown dorsally, fading ventrally, with ventral area of branchiostegite pale bluish cream. Rostral margin and cephalic part of postorbital ridge bright red to reddish orange, and cephalic half of rostrum more red than brown. Color of abdominal terga same as dorsum of carapace with caudal margin of each tergum bearing narrow, red transverse band; pleura pale cream with pinkish suffusion. Telson and uropods pale tan with median ridges on rami of latter dark reddish brown; cephalic section of telson with triangular dark reddish brown patch at base and narrow, lateral marginal bands of similar color. Antennular peduncle cream tan, mottled with brown; flagella tan. Antennal scale tan with dark reddish brown lateral margin; peduncle and flagellum mostly brown. Cheliped basically pale yellowish tan overlain by reddish brown to black in following areas: dorsodistal region of merus, dorsal surface of carpus, dorsomesial half of palm of chela, ridge at base of dactyl, proximodorsal and proximomesial part of dactyl, and proximodorsal part of fixed finger. Tubercles in dark areas cream to light tan; ridges and distal portions of fingers of chela bright red; articular knobs on chela also frequently bright red. Remaining pereiopods basically tan with dorsal portion of distal region of merus, dorsal part of carpus, and proximal part of propodus with reddish brown suffusion.

TYPES.—The holotypic male, form I, allotypic female, and morphotypic male, form II, are deposited in the National Museum of Natural History, Smithsonian Institution, numbers 129758, 146601, and 146602, respectively, as are the paratypes consisting of 5I, 5II, 9, 4j, 2j, 5 ovigerous , and 2 with young.

Measurements (mm)

TYPE-LOCALITY.—Field on west side of Holly Creek (farm of Homer Robinson) about one mile northeast of Chatsworth, Murray County, Georgia. At the time the holotype was collected, the field had not been recently plowed, and the eroded chimneys of a number of burrows were evident. The soil consisted of a sandy clay, and the water table in the comparatively simple burrow was situated at a depth of about one meter. Specimens of both C. (L.) acanthura and C. (D.) cymatilis were dug from burrows some distance from the creek. Nearby, closer to the stream, a specimen of C. (D.) striatus was also obtained from a burrow.

RANGE.—The range of this crayfish encompasses the Tennessee Basin in Alabama, northwestern Georgia, and presumably in southeastern Tennessee, although I have seen no specimens from the latter; it occurs also in the Coosa Basin from its headwaters in Georgia to Chilton County, Alabama, and in headwater areas of the Black Warrior River in Blount and Tuscaloosa counties, Alabama. In the Chattahoochee watershed, it reaches as far south as Russell County, Alabama.

In Georgia (Figure 87), C. (L.) acanthura appears to be concentrated in the Ridge and Valley, Blue Ridge, and upper Piedmont provinces, where it occurs in the watersheds of Chattanooga and South Chickamauga creeks and the Hiwassee River (all in the Tennessee Basin) and in the Chattooga, Conasauga, Coosawattee, and lower Etowah drainage systems in the Coosa Basin. It has also been found in the Tallapoosa watershed in Carroll County and in the Chattahoochee and Ocmulgee basins in De Kalb and Walton counties.

SPECIMENS EXAMINED.—I have examined a total of 249 specimens from Alabama (35) and Georgia (213) of which there are 6I, 9II, 13, 5 ovigerous , 2 with young, 112 j and 103 j. The counties and number of localities in each are as follows (the localities from which the type specimens were collected are noted in brackets). ALABAMA: Blount (1); Calhoun (2); Cherokee (1); Chilton (1) [trib to Waxahatchee Creek 1.5 mi S of Shelby Co line on US Hwy 31, 3, 1 with young, 25 Apr 1970, K. R. Martin, HHH]; Lauderdale (1); Limestone (1); Shelby (2); St. Clair (3) [trib of Big Canoe Creek 12.5 mi SE of Oneonta on US Hwy 31, 1I, 1II, 1 ovig, 28 Apr 1970, B. R. Ford, P. L. Holcomb, HHH; 4.1 mi E of Blount Co line on US Hwy 341, 1II, 2j, 1j, 1 May 1968, HHH]; and Tuscaloosa (1). GEORGIA: Bartow (1); Carroll (1); Catoosa (2); Chattooga (2); De Kalb (2) [Lullwater Biol Field Sta near NE city limits of Atlanta, 1II, 23 May 1969, J. L. Boyce, HHH]; Fannin (2); Floyd (7); Gilmer (2) [Hells Creek to Carters Reservoir between St Rtes 5 and 145, 1 ovig, 28 Apr 1967, Torgny Unestam, HHH]; Gordon (2) [1.8 mi N of Calhoun on St Rte 41, 1I, 1, 2j, 12 Apr 1958, T. L. Johnson, HHH]; Murray (8) [type-locality, 1I, 25 Apr 1968, E. T. Hall, Jr., HHH; near W city limits of Chatsworth off Chestnut Street, 1I, 4 Apr 1973, C. S. Dunn; mountain branch to Conasauga River near Chatsworth, 3II, Dec 1937, Charles Harris]; Polk (2) [Euharlee Creek at Rockmart, 1 with young, 1 May 1967, HHH]; Walton (2) [Near Shiloh Baptist Church about 3.5 mi NE of Loganville on St Rte 8, 1I, 1, 24 May 1969, H. E. Hale, HHH; 3 mi W and about 1 mi N of Between, off US Hwy 78, 1, 24 May 1969, HEH, HHH]; Whitfield (10). A few of the Georgia localities are so close to others that they could not be included in Figure 87.

VARIATIONS.—While a number of variations have been noted, none are associated with a restricted part of the range of the species. Chief among them are differences in the relative lengths of the areola and rostrum, which are reflected in the proportions cited in the “Diagnosis.” In addition, the rostral margins vary from being strongly convergent to almost subparallel, the latter condition being particularly conspicuous in the young, which also bear marginal spines at the base of the acumen. The development of the spines on the uropods and telson seems, at least in part, to be dependent upon the stage in the molting cycle. More recently molted individuals have longer spines, but the spines on the caudal section of the telson exemplified by the allotype (Figure 86c) and morphotype are by no means common. Differences in tubercle counts vary little, except in regenerated appendages, from the range encompassed by the primary types. The first pleopods of the male are remarkably uniform, and the chief differences noted in the annulus ventralis involve the cephalomedian furrow that is hardly discernible in some specimens.

SIZE.—The largest specimen available is an ovigerous female, the carpace length of which is 39.2 (postorbital carapace length, 34.2) mm. The corresponding lengths of the largest first form male are 37.2 (32.0), of the smallest first form male 26.8 (22.6), and of the smallest ovigerous female 29.6 (24.7) mm.

Cambarus (L.) acanthura

E Cymocythere cyma: Gordon (Hart and Hart, 1974:44) Uncinocythere simondsi: Floyd (Hart and Hart, 1974: 134)

Cambarus (Lacunicambarus) acanthura Hobbs

Cambarus (Lacunicambarus) acanthura Hobbs, 1981:215, figs. 25g, 84a, 85–87, 220.

Cambarus acanthura.—Bouchard, 1982:90.

TYPES.—Holotype, allotype, and morphotype, USNM 129758, 146601, 146602 (male I, female, male II); paratypes, BMNH, USNM.

TYPE LOCALITY.—Field on west side of Holly Creek (farm of Homer Robinson) about one mile northeast of Chatsworth, Murray County, Georgia.

RANGE.—Tennessee Basin in Alabama, southwestern Tennessee, and northwestern Georgia; Coosa Basin from its headwaters in Georgia to Chilton County, Alabama, and in headwaters of the Black Warrior River in Blount and Tuscaloosa counties, Alabama; Chattahoochee Basin from Walton and De Kalb counties, Georgia, to Russell County, Alabama; and in the upper Ocmulgee Basin in Georgia.

HABITAT.—Burrows and streams.

Lacunicambarus acanthura, the thornytail crayfish, is a species of crayfish in the family Cambaridae. It is found in the southeastern United States.