Cambarus (Hiaticambarus) lentiginosus, Jones, Danny R. & Eversole, Arnold G., 2016

Jones, Danny R. & Eversole, Arnold G., 2016, A New Crayfish of the Genus Cambarus (Decapoda: Cambaridae) From the Flint River Drainage in Northern Alabama and South Central Tennessee, U. S. A., Zootaxa 4103 (1), pp. 43-54 : 45-53

Cambarus (Hiaticambarus) lentiginosus , new species

Figs. 6 , 7 , Table 1

Cambarus (Hiaticambarus) sp.— Cooper and Hobbs, 1980:17, 23

Diagnosis. Body and eyes pigmented. Rostrum lacking marginal spines or tubercles; margins thickened and strongly tapering; concave dorsally and excavate longitudinally; terminating in long, evenly tapering acumen; length constituting 14.5–18.5% (x = 16.9%, n = 88, SD = 0.01) of CL. Acumen slightly more convergent than rostrum and terminating in small dorsally directed corneous tubercle; usually with short median carina (n = 72) but sometimes without (n = 20); length constituting 32.3–56.0% (x = 39.0%, n = 88, SD = 0.05) of rostrum length.

Carapace subovate and compressed dorsoventrally. Areola length constituting 34.3–38.3% (x = 36.1%, n = 90, SD = 0.01) of CL and 41.6–46.1% (x = 43.4%, n = 87, SD = 0.01) of PCL. Areola 2.3–3.2 (x = 2.7, n = 91, SD = 0.2) times as long as wide, punctate, branchiocardial grooves parallel or subparallel, with 7–12 (modes = 9, 10, n = 91) punctations across midlength. Postorbital carapace length 81.4–85.6% (x = 83.1%, n = 79, SD = 0.01) of CL. Postorbital ridge terminating cephalically in small, corneous, anterodorsally directed tubercle, reduced or absent in abraded, late intermolt individuals. Cervical spine reduced to small flattened tubercle, sometimes flanked by 1–2 smaller flattened tubercles. Hepatic spine absent; branchiostegal spine reduced to diminutive corneous tubercle. Suborbital angle acute, bearing corneous tubercle on apex. Antennal scale widest at or near midlength, 2.1–2.9 (x = 2.5, n = 92, SD = 0.16) times as long as wide, lateral margin thickened and terminating distally in long corneous spine; mesial margin of lamella subparallel to lateral margin, sharply angling to distal margin. Basis of antennal peduncle with minute distolateral corneous tubercle; ischium of peduncle without ventral spine or tubercle. Cephalomedian lobe of epistome subtriangular; epistomal zygoma moderately arched. Chela with widely gaping fingers, with conspicuous tuft of setae along opposable base of fixed finger and sparser setation along base of opposable margin of dactyl; lateral margin of propodus rounded and without costa, lacking impression at base of fixed finger; dorsal and ventral surfaces of fingers without longitudinal ridges. Opposable margins of fixed finger and dactyl with stout, rounded tubercles; second tubercle from base of dactyl conspicuously larger than others; distal end of fixed finger with tubercle ventral to tubercle row. Chela with single row of 6–9 (mode = 8, n = 77) strongly depressed tubercles along mesial margin of palm, barely evident in silhouette, distal tubercles usually marked only by punctation, without part of second row dorsolaterally. Palm of chela 1.4–1.8 (x = 1.6, n = 80, SD = 0.06) times as wide as deep and 1.2–1.6 (x = 1.3, n = 80, SD = 0.07) times as wide as length of mesial margin of palm. Fixed finger and dactyl relatively long, dactyl 1.4–1.7 (x = 1.5, n = 78, SD = 0.06) times length of mesial margin of palm. Hook on ischium of third pereopod of males, large and overreaching basioischial articulation in form I males, weakly developed and not overreaching articulation in form II males, hook opposed by small tubercle on basis. Coxa of fourth pereopod of males with caudomesial boss. Pleura of third through fifth abdominal segments with weakly oblique cephaloventral margin, angular caudoventrally, ventrally obtuse and broadly rounded.

First pleopods of form I male symmetrical and either contiguous or separated basally; distal half of appendage angled cephalically to proximal half at angle of about 17 degrees; both terminal elements moderately short but extending past greatest width of appendage; central projection corneous, bladelike, not tapering, recurved at about 135 degrees to distal portion of appendage, with distinct subapical notch directed proximally; mesial process inflated, membranous, with inflated tip disposed at about right angle to shaft of appendage and slightly laterally. First pleopod of form II male differs from that of form I male in the following respects: pleopods separated basally; central projection bulbous and not corneous, lacking subapical notch; juvenile suture present on basal third of appendage. Annulus ventralis 1.3–1.6 times as wide as long (x = 1.5, n = 35, SD = 0.08), shallowly embedded and barely moveable, asymmetrical, caudodextral wall convex, caudosinistral wall subangular; cephalic area less sclerotized than caudal area; cephalic area with caudally diverging ridges flanking longitudinal trough; trough deepening caudad, sinus originating under caudal end of sinistral ridge, following reverse S-shaped course before terminating on end of midcaudal wall; sinistrally directed tongue arising from dextral half of annulus and deeply inserted into sinus. Postannular sclerite trapezoidal, about 3 times as wide as long, two–fifths as long as annulus, and three–quarters as wide as annulus. First pleopod uniramous and reaching fossa of annulus ventralis when abdomen is flexed.

Holotypic Male, Form I. Body subovate in dorsal view, dorsoventrally compressed ( Fig. 6 i, 7). Abdomen narrower than cephalothorax (8.2 and 10.1 mm); maximum width of carapace greater than depth at caudodorsal margin of cervical groove (10.1 and 6.4 mm). Areola 2.9 times as long as broad, constituting 36.9% of CL (44.7% of PCL); densely punctate with 11 punctations across narrowest part. Rostrum ( Fig. 6 k) with convergent, thickened margins extending along acumen to apex; reaching midlength of ultimate podomere of antennular peduncle; dorsal surface of rostrum concave and longitudinally excavate, with conspicuous punctations in basal region; median carina running almost entire length of acumen. Subrostral ridge strong and visible in lateral aspect along length of rostrum to base of acumen, then coalescing with rostral ridges and continuing to apex, terminating in anterodorsally directed corneous tubercle; acumen with ellipsoidal carina. Postorbital ridge with shallow groove dorsolaterally, without corneous tubercles. Suborbital angle acute, small corneous tubercle on apex; branchiostegal spine minute, tuberculiform. Cervical spine represented by minute depressed tubercle. Carapace densely punctate dorsally and laterally, median gastric area sparsely punctate; orbital and hepatic areas with few squamous tubercles. Abdomen shorter than carapace (18.4 and 19.5 mm). Pleura ( Fig. 6 j) subangular caudoventrally, cephaloventral margins obliquely rounded, ventral margins obtuse and rounded. Cephalic section of telson with 2 spines in each caudolateral corner (mesial spines moveable); transverse suture clearly defined. Mesial ramus of uropod broadly rounded caudad and with poorly defined submedian ridge bearing weak premarginal spine, weak spine present on distolateral corner. Lateral ramus of uropod with rounded lobe caudad; poorly defined submedian ridge on proximal podomere, transverse suture well defined, distal margin of proximal podomere of each ramus bearing 8 spines along caudal margin and with large moveable spine in caudolateral notch.

Cephalomedian lobe of epistome ( Fig. 6 m) subtriangular with weakly elevated (ventrally) margins, surface flat; main body with small, moderately deep fovea and arched epistomal zygoma, latter flanked anteroventrally by deep ovate pits. Ventral surface of proximal podomere of antennular peduncle with small, acute tubercle at base of distal fifth. Antennal peduncle with minute lateral spine on basis, remaining podomeres lacking spines; flagella broken; antennal scale ( Fig. 6 h) 2.6 times as long as wide, broadest at about midlength, distal spine strong and reaching distal margin of ultimate podomere of antennular peduncle. Ventral surface of ischium of third maxilliped with broad, dense, longitudinal band of plumose setae.

Right chela ( Fig. 6 e) 2.1 times as long as broad, mesial margin of palm occupying 36.1% of its length. Mesial surface of palm without well-defined tubercles but with single row of 9 low elevations including small rounded tubercle at proximal base of mesial row, distal tubercles marked only by punctations; dorsal and ventral surfaces with large, deep punctations; lateral surface rounded with no costa. Fingers widely gaping, proximal half of opposable margin of fixed finger with conspicuous tuft of setae on dorsal and ventral surfaces; neither finger with median longitudinal ridge on dorsal or ventral surface, each with conspicuous deep punctations; opposable margin of fixed finger with row of 7 rounded tubercles extending from base to distal fifth, sixth from base enlarged and ventral to tubercle row, band of minute denticles present on same level as tubercle row, running from corneous tip of finger to enlarged ventral tubercle, from there interrupted by tubercles and continuing to proximal third of finger; opposable margin of dactyl with row of 6 rounded tubercles extending from proximal third to distal fifth of dactyl, second tubercle from base conspicuously larger than other tubercles, minute denticles forming band on same level as tubercles, running from corneous tip of finger to third tubercle from base, from there interrupted by tubercles, continuing along proximal fourth. Lateral surface of fixed finger and mesial surface of dactyl punctate.

Carpus of cheliped with oblique furrow dorsally, dorsal surface with sparse punctations; mesial surface with single large, squat, spike-like tubercle distally and smaller tubercle proximally; ventral surface with few punctations and with subtuberculiform thickening on middistal margin. Merus with one squamous premarginal tubercle dorsally; ventrolateral row represented by 2 tubercles and ventromesial row consisting of 5, distal tubercle of each row squat and spikelike, remaining tubercles low, rounded, and reduced in size. Ventromesial margin of ischium without tubercles. Hook on ischium of third pereopod ( Fig. 6 l) overreaching basioischial articulation and opposed by tubercle on basis. Coxa of fourth pereopod with transverse ridgelike caudomesial boss disposed vertically; coxa of fifth pereopod without boss, ventral membrane sparsely setiferous.

First pleopods ( Fig. 6 a, b, f) reaching coxae of third pereopods, symmetrical, and with gap between their bases. (See “Diagnosis” for description.)

Allotypic Female. Excluding secondary sexual characteristics, differing from holotypic male in the following respects: Abdomen narrower than cephalothorax (9.3 and 9.7 mm); maximum width of carapace greater than depth at caudodorsal margin of cervical groove (9.7 and 7.9 mm). Areola 2.7 times as long as broad, constituting 37.2% of CL (44.1% of PCL); densely punctate with 12 punctations across narrowest part. Rostrum reaching midlength of ultimate podomere of antennular peduncle. Abdomen shorter than carapace (18.5 and 19.1 mm). Cephalic section of telson with 2 spines in each caudolateral corner (mesial spines moveable). Antennal flagella reaching cephalic margin of third abdominal tergum. Antennal scale 2.4 times as long as wide.

Right chela 1.4 times as long as broad, mesial margin of palm occupying 40.0% of its length. Mesial surface of palm without well-defined tubercles but with single row of 7 low elevations, distal elevations marked only by punctations. Fingers moderately gaping; opposable margin of fixed finger with row of 7 rounded tubercles extending from base to distal third, sixth from base enlarged and ventral to tubercle row; opposable margin of dactyl with row of 6 rounded tubercles extending from base to distal third.

Annulus ventralis ( Fig. 6 g) 1.5 times as wide as long. Postannular sclerite trapezoidal, 2.8 times as wide as long, width constituting 73.3% of annulus width. First pleopods uniramous and reaching midlength of annulus ventralis. (See “Diagnosis” for description of annulus ventralis.)

Morphotypic Male, Form II. Excluding secondary sexual characteristics, differing from holotypic male in the following respects: Main body of epistome with small, poorly defined fovea. Dactyl of right chela with minute denticles forming band on same level as tubercles, running from corneous tip of finger to second tubercle from base.

Carpus of cheliped with single large, squat, spike-like tubercle distally and without smaller tubercle proximally; ventral surface with few punctations and with subtuberculiform thickening on middistal margin. Ventromesial row of merus represented by 5 tubercles. Hook on ischium of third pereopod weak and not overreaching basioischial articulation and not opposed by tubercle on basis. Coxa of fourth pereopod without transverse ridgelike caudomesial boss disposed vertically.

First pleopods ( Fig. 6 c, d) reaching coxae of third pereopods, symmetrical, and with gap between their bases. (See “Diagnosis” for description.)

Color Notes. Base color of carapace light tan dorsally, white laterally, carapace almost completely covered dorsally and dorsolaterally with dense tan or rust colored mottling and speckling ( Fig. 7 ); caudal saddle extending cephalad along lateral carapace from dark brown caudal flange of carapace; thoracic section of carapace with tan or rust mottling anterolaterally forming diffuse anterior saddle; mandibular adductor regions obscured by mottling; median gastric area same mottled pattern; rostral ridges golden or brown, floor of rostrum darkening to dark brown at apex; orbital and postorbital ridges tan or rust, hepatic and orbital regions with mottled pattern; first abdominal tergum light brown with darker brown mottling or speckling, remaining terga with white base color and with brown speckling; proximal podomere of telson white, distal podomere gray, uropods gray, uropods and telson with brown mottling and bearing orange spines. Basal podomeres of walking legs with white base color, ischia of last two walking legs with brown mottling dorsally; merus and carpus of each walking leg brown dorsally and laterally; propodus and dactylus of each walking leg bluish olive with brown mottling, and joints of walking legs with light orange or peach pigmentation. Merus of cheliped white with distal one-fifth mottled brown; mottling extending onto carpus with lighter golden base color. Palm of chela of cheliped light golden colored dorsally, overlain with anastomosing pattern of brown; dactylus and finger of propodus brown, olive distally with light orange tips; ridge adjacent to proximal articular condyle of dactylus golden yellow.

Types. The holotype, allotype, and morphotype (CMNH 38566, 38567, and 38568 respectively) are deposited in the crustacean collection at the Carnegie Museum of Natural History (CMNH), as is the paratypic series, comprising collections 1–6 listed in below.

Type locality. Fowler Creek at Elkwood Section Road crossing, 1.5 km (0.9 mi) W of junction with US 231/ 431, north of Fisk, Alabama, 34.9765 degrees north latitude, 86.5857 degrees west longitude (North American Datum of 1927). Nearly all of the specimens were collected from a series of riffles just downstream of the road crossing. During collections events, these riffles were ca. 1.5 – 2 m wide and 0.25 m deep and flow was low or moderate. The substrate in the riffles was comprised of deeply layered small cobble and gravel overlying coarse sand. Upstream and downstream of the riffle area the stream was pooled with little flow; we collected no specimens from those sections.

Range and specimens examined. We have collected this crayfish only from the Flint River drainage of Alabama and Tennessee. We have attempted to find it in adjacent and other watersheds in the region but were not successful. We have examined 96 specimens from the following localities. ALABAMA. Madison County: (1a) Type-locality, 7♂ I, 2 ♂ II, 3♀, 19 Apr. 2007, Danny R. Jones ( DRJ), Guenter A. Schuster ( GAS), CMNH 38569; (1b) 13 ♂ I, 28♀, 23 Oct. 2005, DRJ, GAS, CMNH 38570; (2) Flint River at Bobo Section Road crossing, east of Fisk, AL, 4 ♂ I, 2j♂, 1j♀, 14 Apr. 2007, DRJ, GAS, CMNH 38571. TENNESSEE. Lincoln County: (3) Flint River at State Route 275 crossing, about 3.3 air km (akm) SW of Flintville TN, 6 ♂ I, 24 Apr. 2006, DRJ, Richard C. Harrington ( RCH), CMNH 38572; (4) Mule Pen Creek at Mason Road crossing southeast of Flintville TN, 4♂ II, 2♀OV, 13 May 2005, DRJ, RCH, P.R. Hollinsworth ( PRH), CMNH 38573; (5) Mule Pen Creek at Wells – Lee Road crossing, about 1 akm southeast of Flintville TN, 13♂ II, 1♀, 13 May 2005, DRJ, RCH, PRH, CMNH 38574; (6) Campers Branch at State Route 275, about 4 akm southeast of Belleview TN, 1♂ I, 8♂ II, 1♀, 13 May 2005, DRJ, RCH, PRH, CMNH 38575.

Variations. Little variation was noticed in the material examined, none of which was correlated with geography, stream size, or carapace length. In a few individuals the acumen was wide and short, so that the acumen appeared constricted instead of evenly tapering. In about 21.7% of the material examined, the rostral carina was reduced or not conspicuous. In most individuals the suborbital angle was acute, but in a few it was subacute. The bases of the gonopods in form I males were normally separated, but in 25% of the specimens examined, they were contiguous. In a few specimens, the dorsal carapace saddles were very faint but still discernable. In some specimens structure and orientation of the annulus ventralis was a mirror image of the description in the diagnosis.

Size. The largest specimen collected was a form I male with a CL of 21.7 mm (PCL = 18.3 mm). The smallest form I male collected had a CL of 13.6 mm (PCL = 11.1 mm). The largest form II male in the collections had a CL of 20.1 mm (PCL = 17.0 mm). The largest female in the collections had a CL of 20.2 mm (PCL = 17.1 mm).

Life history notes. Collections were available for only three months of the year: April, May, and October. Form I males were found in collections in each of those months, but were represented by only one individual in May collections. Form II males were found in each month, but were represented by only two individuals in the April collections. Ovigerous females (n = 2) were found only in May.

Ecological notes. This crayfish appeared to be an inhabitant of moderate to swiftly flowing sections of streams, and was not collected in pools or slack water during this study. Like other Hiaticambarus species that prefer swift flowing water, this species appeared to prefer a streambed of clean coarse sand and gravel, overlain with layered cobble and small boulder sized stones. This species inhabits the interstices of these habitats, and can reach high densities. In riffles at the type locality, the substrate was deeply layered and density of adult individuals appeared to be very high.

Relationships. The relationships of this crayfish with other species of the subgenus are unclear. It has morphologic affinities with the group of species containing C. longirostris , C. longulus Girard, 1852 , and C. manningi Hobbs, 1981 . These affinities include a rostrum without marginal spines and an overall shorter, more robust chela. However, the opposable margins of both the dactyl and the fixed finger bear well developed, elevated tubercles, whereas those of C. longirostris , C. longulus , and C. manningi bear low, flattened tubercles that are scarcely, if at all, elevated.

Crayfish associates. This crayfish has been collected with C. (Depressicambarus) graysoni Faxon, 1914 , O. (Trisellescens) cooperi Cooper and Hobbs, 1980, and O. (Procericambarus) mirus ( Ortmann, 1931).

Conservation status. Using the methodology used by Taylor et al. 2007, the following conservation status rankings are given for this crayfish: E (Endangered), American Fisheries Society status; G1, global heritage ranking; and S1, state heritage rankings for Alabama and Tennessee. Criteria for these listings are restricted range and the potential for the destruction, modification, of reduction of this species’ habitat and range.

Etymology. The specific epithet lentiginosus is from Latin, and means full of freckles or spotted, in reference to the pigmentation pattern of the species.

Suggested Vernacular Name. The suggested vernacular name for this crayfish is the Speckled Crayfish.

Figures

FIGURE 6. Cambarus (Hiaticambarus) lentiginosus (all from holotype except c and d from morphotype, and g from allotype): a, c, mesial view of first pleopods; b, d, lateral view of first pleopods; e, dorsal view of distal podomeres of cheliped; f, caudoventral view of first pleopods; g, ventral view of annulus ventralis; h, dorsal view of antennal scale; i, lateral view of carapace; j, lateral view of abdomen; k, dorsal view of rostrum showing carina on acumen; l, ischium and basis of third pereopod; m, ventral view of epistome.

FIGURE 7. Cambarus (H.) lentiginosus form I male from type locality.

Tables

TABLE 1. Standard measurements (mm) of type specimens of C. lentiginosus.

	Holotype	Allotype	Morphotype
Carapace
Depth	6.4	7.9	7.3
Width	10.1	9.7	9.9
Total Length	19.5	19.1	19.0
Postorbital length	16.1	16.1	16.0
Areola
Width	2.5	2.6	2.5
Length	7.2	7.1	7.1
Rostrum
Width	2.4	2.5	2.3
Length	3.4	3.0	3.0
Chela
Mesial palm length	6.5	5.2	6.2
Palm width	8.4	9.7	7.9
Lateral margin length	18.0	13.7	16.2
Dactyl length	10.7	7.8	9.3
Abdomen
Width	8.2	9.3	7.6
Length	18.4	18.5	17.1