Cambarus strigosus Hobbs 1981

Cambarus (Depressicambarus) strigosus

Cambarus sp.—Wharton, 1978:46.

DIAGNOSIS.—Eyes small. Rostrum without marginal spines or tubercles and lacking median carina. Carapace with cervical tubercles scarcely larger than others nearby. Areola linear to 44.5 times as long as broad, constituting 39.4 to 42.6 percent of entire length of carapace (45.3 to 48.8 percent of postorbital carapace length) and never with more than 1 punctation in narrowest part. Suborbital angle broadly rounded or obsolete. Postorbital ridge terminating cephalically without spines or tubercles. Antennal scale about 2.7 times as long as broad, widest distal to midlength. Palm of chela with 5 to 8 tubercles in mesialmost row. First pleopod of first form male with central projection, although arched, not reaching proximally to level of bulbous part of mesial process and provided with conspicuous subapical notch; mesial process strongly inflated proximally, with slender subacute apical terminal, and bearing row of plumose setae along caudomesial surface; caudal knob vestigial. Abdomen conspicuously reduced. Color mostly pale orange tan with dark brownish to black and orange markings. Female with first pleopod present.

HOLOTYPIC MALE, FORM I.—Body subovate, strongly compressed (Figure 56a,j). Abdomen conspicuously narrower than thorax (9.9 and 13.5 mm); maximum width of carapace greater than height at caudodorsal margin of cervical groove (13.5 and 12.6 mm, respectively). Areola linear along much of its length with no room for punctations; length 41.8 percent of total length of carapace (47.8 percent of postorbital carapace length). Rostrum with thickened convergent margins contracted rather suddenly at base of short subtriangular acumen, latter reaching distal margin of penultimate podomere of antennular peduncle; dorsal surface of rostrum deeply concave with comparatively few punctations except basally. Subrostral ridge moderately strong and evident in dorsal aspect to base of acumen. Postorbital ridge rather strong, ending abruptly anteriorly, lacking spine or tubercle, and swollen caudally. Suborbital angle poorly developed and rounded; branchiostegal spine lacking, only broad obtuse angle replacing it. Cervical spine represented by tubercle only slightly larger than others on branchiostegal region and smaller than several in hepatic and anteroventral branchiostegal regions. Carapace mostly punctate dorsally but bearing paired, slightly elevated, polished areas between mandibular adductor regions; lateral surface of cephalic section, except for anterior part of orbital and posterior part of hepatic regions, tuberculate. Abdomen shorter than carapace (26.0 and 30.1 mm), pleura short, subtruncate ventrally and rounded caudoventrally (Figure 39j). Cephalic section of telson with single fixed spine in each caudolateral corner. Proximal podomere of uropod lacking spines; mesial ramus of uropod with moderately well developed submedian ridge terminating distally in spine, latter almost reaching distal margin of ramus, lateral margin of ramus with distolateral spine (Figure 39l).

Cephalomedian lobe of epistome (Figure 56g) subpentagonal with short rounded anteromedian projection; margins thickened and elevated ventrally; main body with small but distinct submedian fovea; epistomal zygoma arched. Ventral surface of proximal podomere of antennular peduncle with small spine at base of distal fourth. Antennal peduncle lacking spines; flagellum reaching fourth abdominal tergum; antennal scale (Figure 56i) about 2.7 times as long as wide, broadest distal to midlength; distomesial border forming broad gentle arc, dorsal surface of lateral part of thickened area with conspicuous, deep setiferous punctations, distolateral spine strong and reaching distal margin of penultimate podomere of antennular peduncle. Mesial half of ventral surface of ischium of third maxilliped with 2 rows of clusters of long stiff setae, submarginal lateral row of much smaller plumose ones, and 1 small cluster near base of polished lateral half; distolateral extremity of dextral member acute (sinistral member rounded, probably resulting from injury).

Right chela (Figure 56l) 2.3 times as long as broad, mesial margin of palm occupying slightly more than one-third of its length. Mesial surface of palm with 3 well-defined rows of tubercles, mesialmost of 6, adjacent dorsolateral one of 7 (left with 6), and ventrolateral one of 5 (left with 4); more than mesial half of both dorsal and ventral surfaces tuberculate, tubercles becoming smaller and more squamous laterally; lateral part of both surfaces with setiferous punctations. Ventral surface of palm with conspicuous distomedian tubercle and another large one on ridge opposite base of dactyl. Both fingers with well-defined submedian longitudinal ridge flanked by setiferous punctations on dorsal and ventral surfaces; opposable margin of fixed finger with row of 6 (left with 7) tubercles (third from base largest) along proximal three-fifths, large tubercle on lower level at base of distal third, and single (double distally) interrupted row of minute denticles extending from fourth tubercle from base to corneous tip, lateral margin of finger costate, with costa extending proximally along slightly more than distal half of palm and bearing single row of setiferous punctations; opposable margin of dactyl with row of 10 (left with 9) tubercles (fourth from base largest) and interrupted row of minute denticles extending distally from fourth tubercle from base to corneous tip of finger, mesial surface tuberculate along proximal two-thirds and punctate distally.

Carpus of cheliped with deep oblique submedian furrow dorsally, area mesial to it mostly tuberculate and that lateral to it punctate; mesial surface with large spikelike tubercle and smaller one proximal to it; ventral surface with 2 marginal tubercles (strong subacute median one and less conspicuous more rounded one on articular knob) and smaller one proximomesial to distomedian tubercle; lateral surface punctate. Merus with 2 (3 on left) prominent premarginal tubercles dorsally; ventrolateral row of 3 (only 2 well developed on left) tubercles, and ventromesial one of 12 (11 on left); podomere otherwise polished and with fine punctations laterally and similar ones along with very small tubercles mesially. Ventromesial margin of ischium with row of 4 tubercles.

Ischium of third pereiopod comparatively slender and bearing simple hook extending proximally beyond basioischial articulation (Figure 56h); hook not opposed by tubercle on basis. Coxa of fourth pereiopod with moderately prominent caudomesial boss and strongly elevated (ventrally) ridges mesially; coxa of fifth pereiopod lacking boss but with ventral membrane bearing setae.

First pleopod (Figure 56b,d,f) reaching coxa of third pereiopod and as described in “Diagnosis.”

ALLOTYPIC FEMALE.—Differing from holotypic male in following respects: rostrum, with margins much more strongly convergent, reaching midlength of penultimate podomere of antennular peduncle; cervical tubercle slightly more conspicuous; epistome subtrapezoidal; chelae with mesialmost row of tubercles on palm consisting of 6, dorsolateral row (poorly defined on right) of 5, and adjacent ventrolateral row of 2 (left with only 1 representing row); less than mesial half of dorsal surface of palm tuberculate; tubercle on ventral ridge of palm at base of dactyl rudimentary; fixed finger of left chela atypical, bearing row of 8 tubercles (second from base largest) and additional lower row of 3 tubercles between levels of fifth and seventh tubercles in upper row; mesial surface of carpus lacking small proximal tubercle; merus with ventrolateral row of 4 tubercles on right (3 on left) and ventromesial row of 10 (11 on left). (See “Measurements.”)

Annulus ventralis (Figure 56k) approximately 1.4 times as broad as long and strongly asymmetrical; cephalic two-fifths less calcified than caudal region and bearing shallow triangular median depression flanked by low caudally diverging ridges; caudal part of depression constricting where abutting transverse ridge, and becoming troughlike and turning sinistrally, initiating S- shaped sinus. Latter traversing massive caudal half of annulus, terminating slightly anterior to caudal margin. Surface of sinistral half of caudal region tilted but rather flat, marked by few low ridges mesially; dextral part, in contrast, greatly elevated ventrally and more strongly calcified than sinistral part; tongue from latter disappearing beneath wall of swollen dextral side. Postannular sclerite twice as broad as long, little more than half as long and two-fifths as wide as annulus, its ventral surface densely punctate. First pleopod reaching at least midlength of annulus when abdomen flexed.

MORPHOTYPIC MALE, FORM II.—Differing from holotype in following respects: cephalic section of telson with additional movable spine in caudodextral corner; both lobes of proximal podomore of uropod with spine; cephalomedian lobe of epistome almost square and bearing small, rounded, anteromedian projection; antenna reaching third abdominal tergum; distolateral extremity of ischium of third maxilliped produced in acute prominence; mesial margin of palm of right chela with mesialmost row of 5 tubercles flanked dorsally by row of 6 and ventrally by 2, left chela with 7, 5, and 0, respectively; ventral surface of palm with 2 tubercles on ridge flanking base of dactyl; opposable margin of fixed finger of chela with fourth tubercle from base largest; corresponding margin of dactyl with 11 tubercles; merus of right cheliped with ventrolateral row of 6 tubercles and ventromesial one of 9, that of left cheliped with 6 and 12, respectively. Hooks on ischia of third pereiopods much reduced in size, and boss on coxa of fourth pereiopod less prominent. (See “Measurements.”)

First pleopod (Figure 56c,e) differing from that of holotype most conspicuously in lacking setae along caudal surface of mesial process and in more swollen, noncorneous central projection; former also with prominence on extremity much smaller and rounded.

COLOR NOTES (Figure 38e).—Carapace predominately olive dorsally, fading ventrally on branchiostegites to pinkish cream. Rostral margins, subrostral ridges, postorbital ridges, and small paired spots in posterior gastric region orange; remainder of rostral, orbital, and antennal areas adjacent to subrostral ridges dark olive, and mandibular and hepatic regions olive suffused with orange. Abdominal terga mostly olive but each with narrow orange band on caudal margin; pleura pinkish cream to cream. Telson and uropods pale olive but with margins and transverse sutures orange. Antennular and antennal peduncles dark olive with orange flanking articulations; flagella dark to pale olive. Third maxilliped with basal podomeres pinkish cream and more distal ones pale olive; proximal and distal ends of distal 3 podomeres light orange. Cheliped with coxa and basis cream, ischium with increased suffusion of orange distally, and with dorsal surface dark olive intensifying and broadening distal to midlength but with major dorsal tubercles orange; carpus orange, mottled with dark olive dorsally, particularly mesially and distally; tubercles and dorsodistal articular area marked with orange; dorsomesial three-fourths of palm dark bluish green, fading laterally to orange, with orange tubercles and condyle flanking dactyl. Both fingers dark bluish green dorsally with mesial and lateral areas grading into orange on ventral surface; tips of fingers orange yellow. Remaining pereiopods pinkish cream basally, becoming pale olive on ischium and merus, but fading on propodus and dactyl. Sternal area cream to pinkish cream.

Measurements (mm)

TYPES.—The holotypic male, form I, allotypic female, and morphotypic male, form II (numbers 148284, 148574, and 148575, respectively), are deposited in the National Museum of Natural History, Smithsonian Institution, as are the paratypes consisting of two first form males, three second form males, 16 females, three juvenile males, five juvenile females, and three ovigerous females. (While the juvenile and second form males were being maintained alive in the laboratory, anticipating their attaining, at least, a greater size the juvenile male molted to form I.)

TYPE-LOCALITY.—Roadside ditch within 30 meters of Susan Smith Branch (tributary to Long Creek and the Broad River) west of State Route 17 on unnumbered county road, Wilkes County, Georgia. The ditch supported a dense growth of Persicaria sp. flanking several small pools on a sandy clay substrate. The burrows were comparatively simple and marked by low chimneys. One of the burrows that was excavated during October had two chimneys, and passageways from them united at a depth of some 20 centimeters and continued as a single vertical tunnel to a depth of about one meter; others that were opened in the spring descended well beyond the one-meter mark. The most conspicuous trees in the nearby woods were Pinus sp., Liriodendron tulipifera, and Platanus occidentalis.

RANGE.—This crayfish is known from only five localities in the Broad and Little river basins (tributaries of the Savannah River) in Elbert, Oglethorpe, and Wilkes counties, Georgia. These streams lie wholly within the Piedmont Province. Almost certainly the range of C. (D.) strigosus is greater that that indicated on Figure 41, for I can fathom no reason why it should not be more widespread in the basins of the Broad and Little rivers. Thorough searches have not been made for it in many parts of either basin. Appearing to vicariate for it in abutting or nearby watersheds are the following: in the upper Chattahoochee, C. (J.) nodosus; in the Ogeechee and Savannah (to the south), C. (D.) reflexus; in the Ocmulgee-Oconee, C. (D.) striatus and C. (D.) truncatus; and in the Etowah, C. (D.) striatus.

GEORGIA SPECIMENS EXAMINED.—I have examined 35 specimens from the following localities. Elbert County: (1) Nancy Hart State Park 1.6 mi E of St Rte 17 on Rte S2215, 3, 2j, 1j, 2 Apr 1978, R. J. Dubois, D. J. Peters, J. E. Pugh, HHH, collectors. Oglethorpe County: (2) seepage area adjacent to Big Indian Creek 4.5 mi N of Lexington on St Rte 77, 3, 1j, 2 Apr 1978, RJD, DJP, JEP, HHH; 3II, 3, 3 ovig , 21 May 1979, E. T. Hall, Jr., HHH; 1I, 3, 23 May 1979, W. D. Kennedy, ETH, HHH; (3) roadside ditch near Goosepond Creek 2 mi E of St Rte 77 on Co Rd 195, 1II, 2 Apr 1978, RJD, DJP, JEP, HHH; 1I, 1, 22 May 1979, WDK, HHH. Wilkes County: (4) type-locality, II, 1j, 4 Oct 1977, T. A. English, Jr., HHH; 2, 1j, 2 Apr 1978, RJD, DJP, JEP, HHH; (5) along Beaver Dam Creek 4.1 mi SW of Washington on St Rte 44, 2, 1j, 1j, 3 Apr 1978, RJD, DJP, JEP, HHH.

VARIATIONS.—In view of the limited number of specimens available from so few nearby localities, it is not surprising that the variations noted are so few, and, for the most part, hardly worthy of recording. The limits of variation in ratios of the length of the areola to its width, the carapace length, and the postorbital carapace length are cited in “Diagnosis.” Whereas the numbers of tubercles in the mesialmost row on the palm of the chela range from five to eight, the usual is six, and on only one chela of a single specimen were there eight. The numbers of tubercles comprising the row on the opposable surface of the fixed finger of the chela range from five to seven, of which the third from the base is usually largest; those on the corresponding margin of the dactyl range from six to 10, and the fourth from the base is almost always largest. The mesial surface of the carpus of the cheliped bears from one to three tubercles, the latter occurring more infrequently than one or two; the number of spines on the ventral surface of the merus ranges from seven to 11 in the mesial row and two to six in the lateral one, the most frequently occurring are nine and four, respectively; and the row of tubercles on the mesial margin of the ischium consists of two to four, three most commonly. Two of the females, one from Elbert County and the other from the type-locality, were predominately dark blue instead of olive and orange.

SIZE.—The largest specimen available is a female having a carapace length and postorbital carapace length of 36.5 (31.9) mm. The smallest and largest first form males have comparable lengths of 29.9 (26.4) and 31.0 (27.2) mm, and of the smallest ovigerous female, 27.2 (24.0) mm.

Cambarus (Depressicambarus) strigosus Hobbs

Cambarus sp.—Wharton, 1978:46.

Cambarus (Depressicambarus) strigosus Hobbs, 1981:134, figs. 23d, 38e, 39j, l, 41, 56, 205.

TYPES.—Holotype, allotype, and morphotype, USNM 148284, 148574, 148575 (male I, female, male II); paratypes, USNM.

TYPE LOCALITY.—Roadside ditch within 30 meters of Susan Smith Branch (tributary to Long Creek and Broad River) west of State Route 17 on unnumbered county road, Wilkes County, Georgia.

RANGE.—Known from only five localities in the Broad and Little river basins in Elbert, Oglethorpe, and Wilkes counties, Georgia.

HABITAT.—Burrows (primary burrower).

Cambarus strigosus, the lean crayfish, is a species of crayfish in the family Cambaridae. It is found in North America.