Cambarus (Hiaticambarus) diupalma, Jones, Danny R. & Eversole, Arnold G., 2015

Jones, Danny R. & Eversole, Arnold G., 2015, Two new crayfishes of the genus Cambarus (Decapoda: Cambaridae) from Northern Alabama and South Central Tennessee, U. S. A., Zootaxa 4058 (2), pp. 151-174 : 167-173

Cambarus (Hiaticambarus) diupalma , New Species

Figs. 12 , 13 , Table 4

Diagnosis. Body and eyes pigmented. Rostrum lacking marginal spines, tubercles, or median carina; margins thickened and strongly tapering; slightly concave dorsally and excavate longitudinally; terminating in long, evenly tapering acumen; length constituting 15.2–18.2% (x = 16.4%, n = 23, SD = 0.01) of TCL. Acumen slightly more convergent than rostrum and terminating in small dorsally directed corneous tubercle; without median carina; length constituting 36.7–51.3% (x = 43.0%, n = 23, SD = 0.04) of RL. Carapace subovate and moderately compressed dorsoventrally. Areola length constituting 36.0–38.3% (x = 37.1%, n = 23, SD = 0.01) of TCL and 43.2–45.5% (x = 44.5%, n = 23, SD = 0.01) of PCL. Areola 3.1–3.8 (x = 3.5, n = 23, SD = 0.2) times as long as wide, punctate, narrowest at midpoint, with 8–12 (mode = 9, n = 24) punctations across narrowest part. Postorbital carapace length 81.8–84.6% (x = 83.6%, n = 23, SD = 0.01) of TCL. Postorbital ridge terminating cephalically in small, corneous, anterodorsally directed tubercle. Cervical spine reduced to small tubercle, flanked by 2–3 smaller or subequal tubercles. Hepatic spine absent; branchiostegal spine reduced to small corneous tubercle. Suborbital angle subacute (n = 16) or obtuse (n = 8), bearing small corneous tubercle on apex. Antennal scale widest at or near midlength, 2.3–2.7 (x = 2.5, n = 23, SD = 0.10) times as long as wide, lateral margin thickened and terminating distally in long corneous spine; mesial margin of lamella subparallel to lateral margin, gently 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 semicircular or triangular; epistomal zygoma moderately arched.

Chela and fingers inflated, fingers widely or moderately gaping in form I males and weakly gaping in form II males and females, usually without conspicuous tuft of setae along opposable base of fixed finger, although setation present in some younger or early intermolt individuals; 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 low, rounded tubercles; third or fourth tubercle from base of dactyl situated ventral to rest of tubercle row; distal end of fixed finger with tubercle ventral to tubercle row. Chela with single row of 8–10 (mode = 9, n = 21) strongly depressed tubercles along mesial margin of palm, barely evident in silhouette, distal tubercles usually absent and marked by punctation, without part of second row dorsolaterally. Palm of chela 1.4–1.6 (x = 1.5, n = 18, SD = 0.06) times as wide as deep and 1.0–1.2 (x = 1.1, n = 18, SD = 0.05) times as wide as length of mesial margin of palm. Fixed finger and dactyl relatively short, dactyl 1.1–1.3 (x = 1.2, n = 18, 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 subangular or angular cephaloventral margin, angular posteroventrally, ventrally acute and rounded.

First pleopods of form I male (based on holotype) symmetrical and either contiguous or separated basally; distal half of appendage angled cephalically to proximal half at angle of about 27 degrees; both terminal elements moderately short but extending past greatest width of appendage; central projection corneous, bladelike, not tapering, recurved at about 130 degrees to distal portion of appendage, with distinct subapical notch directed caudoproximally; mesial process inflated, membranous, with acute fingerlike tip disposed at about right angle to shaft of appendage and slightly laterally; caudomesial face of pleopod angular, forming flattened, shelf-like area. First pleopod of form II male (based on morphotype) 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; caudomesial face of pleopod lacking flattened, shelf-like area.

Annulus ventralis (based on allotype) 1.4–1.5 times as wide as long (x = 1.4, n = 3, SD = 0.06), barely moveable, asymmetrical, caudodextral wall convex, caudosinistral wall angular and slightly concave caudad; cephalic area less sclerotized than caudal area; cephalic area with caudally diverging ridges flanking longitudinal trough; trough deepening and widening caudad, sinus originating under caudal end of dextral ridge, following S– shaped course before terminating on end of midcaudal wall, dextrally directed tongue arising from sinistral half of annulus deeply inserted into sinus. Postannular sclerite crescent shaped, 3 times as wide as long, one–third as long as annulus, and three–fourths as wide as annulus. Female first pleopods uniramous and reaching midlength of annulus ventralis when abdomen flexed.

Holotypic Male, Form I. Body subovate in dorsal view, carapace dorsoventrally compressed, 1.4 times wider than deep. ( Figs. 12 i, 13). Areola 4 times as long as broad, constituting 38.5% of TCL (45.9% of PCL); densely punctate with 11 punctations across narrowest part. Rostrum ( Fig. 12 m) 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. 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. Postorbital ridge short with shallow groove dorsolaterally, terminating cephalically in small corneous tubercle. Suborbital angle obtuse, small corneous tubercle on apex; branchiostegal spine minute, rounded. Cervical spine represented by small, depressed tubercle. Carapace densely punctate dorsally and laterally. Abdomen length 87.0% of TCL; abdomen width 81.3% of carapace width; pleura long ( Fig. 12 j), subangular caudoventrally and cephaloventrally, with acute rounded ventral margins. 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 both lateral rami with 12 small spines and additional smaller tubercles, in addition to these, margin of each podomere with large moveable spine in notch mesial to spine in distolateral corner.

Cephalomedian lobe of epistome ( Fig. 12 k) elliptical with weakly elevated (ventrally) margins, surface flat main body with deep fovea, fovea open cephalically and continuous with base of cephalomedian lobe; epistomal zygoma arched and flanked cephalolaterally by deep, curved elongate pits. Ventral surface of proximal podomere of antennular peduncle with small, acute tubercle at base of distal fourth. Antennal peduncle with minute lateral spine on basis, remaining podomeres lacking spines; flagellum reaching caudal margin of fourth abdominal tergum; antennal scale ( Fig. 12 h) 2.7 times as long as wide, broadest at about midlength, distal spine strong and reaching midlength of ultimate podomere of antennular peduncle. Ventral surface of ischium of third maxilliped with longitudinal band of stiff setae.

Right chela ( Fig. 12 e) 2.1 times as long as broad, mesial margin of palm occupying 43.1% of its length. Mesial surface of palm without well defined tubercles but with single row of 10 adpressed tubercles, distal tubercles marked only by punctations; dorsal and ventral surfaces with large, deep, sparsely placed punctations, lateral surface rounded with no suggestion of costa. Fingers moderately gaping, proximal half of opposable surface of fixed finger without conspicuous tuft of setae; neither finger with median longitudinal ridge on dorsal or ventral surface, each with conspicuous deep punctations; opposable margin of fixed finger with row of 9 low tubercles extending from base almost to end, eighth from base ventral to tubercle row, single row of minute denticles present on same level as tubercle row, running from corneous tip of finger to fifth tubercle from base, from there represented by 1–2 denticles between tubercles along distal half of finger; opposable margin of dactyl with row of 10 low tubercles extending from proximal third to end of dactyl, fourth tubercle from base displaced ventrally, minute denticles forming single row on same level as tubercles, running from tip of dactyl to eighth tubercle from base, from there represented by 1–2 denticles between tubercles along distal fourth of dactyl. Lateral surface of fixed finger and mesial surface of dactyl punctate.

Carpus of cheliped with oblique furrow dorsally, flanked by sparse punctations; mesial surface with single large, squat tubercle; ventral surface with few punctations and without tubercles on distal margin. Merus without premarginal tubercles dorsally; ventral surfaces of merus and ischium without spines or tubercles.

Hook on ischium of third pereopod ( Fig. 12 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. 12 a, b) 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: distal spine of antennal scale reaching distal margin of ultimate podomere of antennular peduncle. Rostrum reaching proximal base of ultimate podomere of antennular peduncle. Areola 3.2 times as long as broad, constituting 37.9% of TCL (44.5% of PCL); densely punctate with 12 punctations across narrowest part. Abdomen length 102.0% of TCL; abdomen width 96.4% of carapace width. Cephalic section of telson with 2 spines in right caudolateral corner (mesial spine moveable), left caudolateral corner with one immovable spine. Right chela 2.0 times as long as broad, mesial margin of palm occupying 42.9% of its length. Mesial surface of palm without welldefined tubercles but with single row of 9 adpressed low elevations, most marked only by punctations. Fingers weakly gaping; proximal half of opposable surface of fixed finger of right chela with sparse tuft of setae, that of left chela with conspicuous tuft; opposable margin of fixed finger with row of 10 rounded tubercles extending from base almost to end, ninth from base ventral to tubercle row, single row of minute denticles present on same level as tubercle row running from corneous tip of finger to seventh tubercle from base, from there represented by 1–2 denticles between tubercles along distal third of finger; opposable margin of dactyl with row of 9 rounded tubercles extending from base almost to end of dactyl, third tubercle from base displaced ventrally, minute denticles forming single row on same level as tubercles, running from tip of dactyl to ninth tubercle from base, from there represented by 1–2 denticles between tubercles along distal half.

Annulus ventralis ( Fig. 12 g) 1.3 times as wide as long, postannular sclerite crescent shaped, concave caudad, 3 times as wide as long, width constituting 76.9% of annulus width. First pleopods uniramous and reaching midlength of annulus ventralis.

Morphotypic Male, Form II. Differing from holotype in the following respects: distal spine of antennal scale reaching anterior margin of ultimate podomere of antennular peduncle, suborbital angle subacute. Ventral surface of ischium of third maxilliped with comparatively sparse, longitudinal band of stiff setae. Areola 3.2 times as long as broad, constituting 37.0% of TCL (43.2% of PCL), with 9 punctations across narrowest part. Abdomen length 96.1% of TCL; abdomen width 87.4% of carapace width. Cephalic section of telson with 1 immoveable spine in each caudolateral corner.

Mesial margin of palm occupying 41.0% of its length and bearingsingle row of 9 low elevations, distal tubercles marked only by punctations. Fingers weakly gaping; opposable margin of dactyl with row of 9 tubercles. Ventrolateral row of merus of cheliped represented by 1 small corneous tubercle and ventromesial row consisting of 4 minute tubercles. Ventromesial margin of ischium without tubercles. Hook on ischium of third pereopod short, not overreaching basioischial articulation, opposed by tubercle on basis. Coxa of fourth pereopod with weakly developed caudomesial boss.

First pleopods ( Fig. 12 c, d) reaching coxae of third pereopods, symmetrical, and with gap between their bases; caudomesial face of pleopod lacking flattened, shelf-like area.

Color notes. Base color of carapace light tan ( Fig. 13 ), branchiostegites gray, caudal saddle barely extending anteriorly from black caudal flange of carapace; mandibular adductor regions with anastomosing pattern of tan over white merging with similar pattern contiguous to anterior margin of cervical groove, posterior and median gastric area tan and darkening anteriorly, rostral ridges orangish or yellowish brown, floor of rostrum tan at base darkening to dark brown anteriorly and laterally, orbital and postorbital ridges dark brown, hepatic region white, and orbital region brown. First abdominal tergum bronze, remaining terga light tan with dark brown caudomesial margin and with lighter pleura, giving impression of faint, dorsomedian stripe on abdomen, both podomeres of telson tan, uropods brown, uropods and telson bearing dark golden spines. Proximal half of merus of cheliped white with distal one-third tan, carpus with base color tan and dorsal groove lighter. Base color of palm of chela of cheliped tan dorsally, overlain with pattern of tan, mostly transverse and sublinear splotches, dactylus and finger of propodus tan. Ischia of walking legs orange dorsally and laterally, merus and carpus of walking legs greenish tan dorsally and laterally, propodus of last three walking legs olive or greenish brown and that of first walking leg white, dactylus of first two walking legs olive, that of the last two orange, joints of walking legs with light orange or peach pigmentation.

Types. The holotype, allotype, and morphotype (38531, 38532, and 38533, respectively) are deposited in the crustacean collection at the Carnegie Museum of Natural History (CMNH), as is the paratypic series, comprising collections 1–2 listed below.

Type locality. Mountain Fork at Old Mountain Fork Road, 2.6 air km northeast of New Market, Madison County, Alabama, 34.9180 degrees north latitude, 86.4012 degrees west longitude, NAD1927. Nearly all specimens were taken from a riffle with predominately boulder and cobble substrate overlying clean coarse sand. The riffle was just downstream from the road crossing and water depth at times of collection was ca. 0.5 m. Immediately downstream of the riffle water depth increased to ca. 1 m and the stream bed was comprised primarily of coarse sand and gravel. Attempts to collect specimens upstream and downstream of the road crossing were unsuccessful.

Range and specimens examined. This crayfish is known only from the type locality ( Fig. 11 ) and the material examined comprises 24 specimens: ALABAMA. Madison County: (1) Type-locality, Mountain Fork at Old Mountain Fork Road, 2.6 air km northeast of New Market, CMNH 38534, 8♂ I, 2♂ II, 5 Apr. 2006, DRJ; CMNH 38535, 11♂ I, 3♀, 22 Oct. 2007, DRJ, GAS. Mountain Fork is a major tributary of the Flint River in Alabama. Intense effort was made in the Market Fork, Flint River, and adjacent drainages to collect specimens of this species at other localities. Although we found similar habitat in these drainages we unable to collect it anywhere other than at the type locality.

Variations. Given that this species is known from only one locality, it was not surprising that no significant variation existed in the available specimens, however, 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 TCL of 26.2 mm (PCL = 22.0 mm). The smallest form I male available had a TCL of 19.4 mm (PCL = 16.2 mm). The largest form II male in the collections had a TCL of 18.1 mm (PCL = 15.1 mm) and the largest female had a TCL of 20.6 mm (PCL = 17.3 mm).

Life history notes. Form I males were collected in April 2006 and 2007. No ovigerous females were collected.

Ecological notes. At the type locality, this crayfish was collected only from boulder/cobble habitat within the riffle and swift run just downstream from Old Mountain Fork Road crossing. It was not collected in the deeper channelized section further downstream, where O. validus ( Faxon, 1914) was the only crayfish collected.

Relationships. Morphologically this crayfish has affinities with C. longirostris and C. andersoni . It differs from both of these species in possessing ventrally angular and acute abdominal pleura and shorter dactylus length. It differs from C. longirostris in having chelae with narrow gape width and longer and wider palms. C. diupalma differs from C. andersoni in having chelae with a longer mesial palm length, possessing a shoulder on the caudomesial face of the form I male gonopod, and in lacking a ventral rostral spine. This crayfish also appears to belong to Hobbs’ (1981) group of more derived Hiaticambarus species.

Crayfish associates. This crayfish has been collected with C. (D.) graysoni and O. (G.) validus .

Conservation status. Using the methodology of 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 is a combination of the Latin words diu, meaning long, and palma, meaning palm, in reference to the long palms of the chelae observed in the species.

Suggested Vernacular Name. The suggested vernacular name for this crayfish is the Mountain Fork Crayfish, in reference to the sole locality and stream from which it is known.

Figures

FIGURE 11. Collection sites for Cambarus (H.) andersoni and C. (H.) diupalma.

FIGURE 12. Cambarus (Hiaticambarus) diupalma (all from holotype except c, 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, ventral view of epistome; l, ischium and basis of third pereiopod; m, dorsal view of rostrum.

FIGURE 13. Cambarus (H.) diupalma form I male from type locality. Photo from Guenter Schuster.

Tables

TABLE 4. Standard measurements (mm) of type specimens of Cambarus (Hiaticambarus) diupalma.

	Holotype	Allotype	Morphotype
Carapace
Total length	26.2	20.3	18.1
Postorbital length	22.0	17.3	15.5
Width	13.9	11.0	9.5
Depth	10.1	8.1	7.2
Areola length	10.1	7.7	6.7
Areola width	2.5	2.4	2.1
Rostrum length	4.2	2.9	2.6
Rostrum width	3.0	3.3	1.9
Gonopod length	6.2	N\A	4.4
Annulus ventralis length	N\A	1.8	N\A
Annulus ventralis width	N\A	2.4	N\A
Antennal Scale
Length	4.4	3.4	3.4
Width	1.6	1.3	1.3
Abdomen
Length	22.8	20.7	17.4
Width	11.3	10.6	8.3
Chela
Lateral margin length	24.8	14.9	13.9
Mesial palm length	10.7	6.4	5.7
Palm width	11.6	7.4	6.7
Dactyl length	13.6	7.8	7.1