Cambarus polypilosus Loughman & Williams, 2018

Loughman, Zachary J., 2018, Cambarus polypilosus, a new species of stream-dwelling crayfish (Decapoda: Cambaridae) from the Western Highland Rim of Tennessee, USA, Zootaxa 4403 (1), pp. 171-185 : 173-183

Cambarus polypilosus Loughman & Williams , sp. nov.

Figures 1–7 , Table 1

Diagnosis. Body and eyes pigmented. Rostrum lanceolate, excavated, and ventrally deflected anteriorly, margins thickened to acumen, and sub-parallel; converging to acumen. Row of setae bundles running parallel along inner margin of rostral margins. Acumen acuminate with prominent dorsally deflected spiniform tubercle at terminus. Areola 2.3–5.8 (? = 3.8, n = 27, σ = 0.8) times as long as wide with 2–3 (usually 2) punctations across narrowest point. Two rows of punctuations, one for each margin, running parallel to inner areola margins; lacking extensive punctations in body of areola. Cervical spines absent; tubercles absent along cervical groove. Mandibular, branchiostegal, and orbital regions of carapace with well-developed tubercles. Postorbital ridge not terminating anteriorly in tubercle or spine. Suborbital angle acute terminating in post-orbital spine. TCL 1.9–2.2 (? = 2.0, n = 27, σ = 0.2) times greater than width.

Form I and II males possessing hook on ischium of third pereopod only; hook gently curved at apex, overarching basioischial joint in form I males, not reaching basioischial joint in form II males; hook not opposed by tubercle on third pereopod boss.

Mesial surface of palm of chela not possessing row of tubercles; adpressed tubercles occasionally present. Ventral surface of palm lacking tubercles. Dorsomedian ridge of fixed finger of propodus pronounced. No lateral impression at base of fixed finger. Setae bundles widely distributed over dorsal and ventral surfaces of chelae; each consisting of 2–4 long setae,> 1.0 mm in length, and 5 or more setae <0.5 mm in length. Dactyl and fixed finger each with sharp corneous subterminal tip; both fingers covered in dense setae. Form I male palm length constituting 82.5–114.5% (? = 92.7, n = 9, σ = 2.8) of palm width and 41.6–45.3% (? = 43.5, n = 9, σ = 1.2) of total propodus length; female dactyl length 38.9–47.7% (? = 43.1, n = 6, σ = 3.6) of total propodus length. Ventral margin of merus with single large distal merus spine, single lateral margin merus spine, and 3–6 (? = 4.0, n = 27, σ = 0.9) ventrolalteral merus spines. Gonopod of form I male with long terminal elements. Central projection sickle shaped and not tapering distally; recurved> 90° to main shaft of gonopod, lacking subapical notch. well defined caudal knob at lateral base of central projection. Mesial process directed approximately 90° to shaft, bent cephalolaterally; inflated proximally with distinct hump; tapering to a point distinctly caudal to slightly cephalic to terminance of central projection; and not projecting beyond edge of gonopod shaft margin. Annulus ventralis immovable; distinctly asymmetrical caudally; cephalic portion with median trough leading to strongly sculptured central fossa; exaggerated “S” bend in sinus terminating at caudal edge.

Holotypic male, form I ( Fig. 2 A–C, G–J , Table 1). Body ( Fig. 2A, G ) compressed dorsoventrally; thoracic section of carapace slightly wider than abdomen. carapace height less than carapace width (8.7 and 8.5 mm, respectively). Carapace depth less than carapace width at caudodorsal margin of cervical groove. TCL 19.2 mm; PCL 16.5 mm. Areola 5.2 times longer than wide, with 1–2 punctations across narrowest part; length of areola 37.0% of TCL (43.0% of PCL). Rostrum narrow with acuminate acumen and moderately excavated equally along length; margins thickened and weakly converging caudal to acumen; floor of rostrum with numerous punctations; a row of setae bundles running parallel to inner edge of rostral margins. Rostrum 1.9 times longer than wide. Rostrum distinctly triangular, ending in dorsally turned corneous tip ( Fig. 2A ). Postorbital ridges short, terminating in blunt tip. Suborbital angle acute, with pronounced spiniform tubercle at apex ( Fig. 2A ). Cervical spine and tubercles absent. Mandibular, branchiostegal, and orbital regions of carapace densely punctate with a few poorly developed tubercles; greatest tubercle density in hepatic region.

Abdomen slightly longer than carapace, pleura rounded cephaloventrally, angled caudoventrally. Cephalic section of telson with 1 large spine in each caudolateral corner. Proximal podomere of uropod with 3 distolateral spines on mesial lobe; median spine, originating from ventral surface, 3 times longer than those flanking; mesial ramus of uropod with median ridge ending distally in distomedian spine not overreaching margin of ramus. Distal margin of proximal segment of lateral ramus of right uropod bearing 12 immovable, small spines.

Cephalomedian lobe of epistome subtriangular, forming sharp angle at junction with endostyle; cephalolateral margins thickened, with right margin extending into right angle; left anterior margin subacute; Zygoma moderately arched ( Fig. 2I ); main body possessing prominent cephalomedian fovea.

Antennal scale broadest distally; lateral margin thickened, terminating in large corneous spine; setiferous mesial margin. Right antennal scale 2.9 mm long, 0.8 mm wide. Tip of right antenna reaching middle of telson when adpressed.

Mesial surface of palm of right chela without well-defined tubercle rows; 2 rows of setae bundles with mesialmost row possessing 5 bundles and second row with 7 ( Fig. 2H ). Palm length 90.3% of palm width; depth of palm 5.1 mm. Ventral surface of palm lacking tubercles. Dorsal longitudinal ridge of dactyl not developed and possessing 7 setae bundles ( Fig. 2H ); dactyl terminating in large corneous spine. Dorsomedian ridge of fixed finger of propodus weakly developed. Lacking lateral impression at junction of fixed finger and palm; numerous setiferous punctations present.

Fixed finger of propodus with sharp, corneous tip. Carpus with prominent dorsal furrow ( Fig. 2H ), surface covered with setiferous punctations; mesial margin with large, procurved spine at about midlength. Distodorsal surface of merus without spines or tubercles; 5 spines on ventral surface of merus consisting of 1 large corneous distal merus spine, 1 lateral merus spine, and 3 ventrolateral merus spines on lateral margin. Hook on ischium of third pereopod only; gently curved at apex, overarching basioischial joint, not opposed by tubercle on base. Form I gonopod as described in diagnosis ( Fig. 2B–C ); tip reaching anterior margin of caudomesial boss of coxa of 4th pereopod when abdomen flexed.

Allotypic female ( Fig. 2F , Table 1). Differing from holotype in following respects; carapace height less than carapace width (6.5 and 7.3 mm, respectively); TCL 15.0 mm, PCL 12.8 mm. Areola length 36.5% of TCL (43.0% of PCL), 2.6 times as long as wide. Mesial surface of chelae with two rows of setae bundles. Mesial most row with 5 bundles; second row with four bundles. Palm length (4.8 mm) 97.0% of palm width (5.0 mm);. All measurements and counts from right chela. Antennal scale 2.7 mm long, 0.7 mm wide. Annulus ventralis as described in diagnosis ( Fig. 2F ); width of postannular sclerite half total width of annulus ventralis; first pleopods uniramous, reaching central region of annulus ventralis when abdomen flexed.

Morphotypic male, form II ( Fig. 2D–E , Table 1). Differing from holotype in the following respects: Carapace height greater than carapace width (5.7 and 6.5 mm respectively); TCL 12.4 mm and PCL 10.4 mm. Areola length 37.0% of TCL (44.2% of PCL), 2.9 times longer than wide. Rostrum margins subparallel and entire to acumen tip; rostrum ventrally deflected and excavated; rostrum 1.8 times as long as wide. Abdomen 12.9 mm long. Mesial margin of palm of cheliped with two rows of setae bundles; mesial-most row with 6 bundles; second row with 4 bundles. Palm length (3.3 mm) 90.8% of palm width (3.6 mm). All measurements and counts from right chela. Antennal scale 2.1 mm long, 1.1 mm wide. Gonopods reaching anterior margin of 4th pereopod caudomesial boss. Central projection curved 90° to shaft ( Fig. 2D–E ). Mesial process tapered, bulbous, directed caudolaterally. Hook on ischium of third pereopod small, not reaching basioischial joint.

Size. Form I male (n = 16) TCL ranges in siZe from 13.3–21.0 mm (11.7–16.8 mm PCL) with a mean TCL of 16.9 mm. Mean TCL of form II male (n = 5) is 13.6 mm, ranging in siZe from 11.5–16.7 mm (PCL 10.0–12.0 mm). Female (n = 6) mean TCL is 16.2 mm and ranges from 14.2–20.1 mm (PCL 12.3–17.1 mm). The largest specimen examined was a form I male with a TCL of 21.0 mm (PCL 16.0 mm).

Color. Carapace ground color of C. polypilosus sp. nov. ( Fig. 3 ) light brown to orange-brown; posterior margin of carapace same as ground color, without saddle. Hepatic and antennal region of carapace with beige punctations. Postorbital ridge same color as carapace. Rostrum margins and acumen cream to orange, orangebrown, olivaceous or tan. Cephalic section of carapace immediately anterior to and including cervical groove light olive-brown; mandibular abductor scars mottled, ranging from light-brown, brown, to dark-brown. Lateral margin of antennal scale olive to light brown; body of antennal scale brown to cream. Antennal flagellum and antennules green-brown, with olivaceous hue; dorsal surface of lamellae tan to brown; ventral surface light-green to olivaceous. Dorsal surface of chelae generally olivaceous or light-brown, with beige punctations. Denticles on opposable surfaces of fingers yellow, white, or tan. Ventral surface of chelae cream or tan. Dorsal surface of carpus orange-brown or olivaceous; region adjacent to and including furrow olive-brown to olive; carpus spine cream. Merus olive-brown or olive. Podomeres of pereopods olivaceous, light brown, or green-brown; joints of pereopod podomeres orange. Dorsal and dorsolateral surface of abdomen same colors as carapace; tergal margins cream; abdomen lacking dorsal stripe. Uropods same colors as abdomen. Ventral surface of abdomen and carapace cream. Dorsal ridge of form I gonopod central projection amber; body of central projection, gonopod, and mesial process tan. Form II gonopod and all associated processes cream. Cephalic portion of annulus ventralis pink to pink-cream; ridge of fossa pink; caudal region of annulus ventralis ranges from pink to cream colored. Specimens occasionally encountered displaying green-yellow or yellow as the dominant dorsal and lateral coloration ( Fig. 4 ).

Type locality. Little Blue Creek, 0.3 km (0.19 mi) from intersection of Little Blue Creek Road and East Blue Creek Road, 6.2 km (3.9 mi) southeast of waverly, Humphreys County, Tennessee, N 36.06733 w 87.72890. At the type locality Little Blue Creek is a moderate-siZed perennial stream with mature mesophytic forests composing the riparian corridor. Stream substrate consists of small cobble and gravel composed primarily of chert, mudstones, and dolostones. Macrohabitat ranges from slow to moderate velocity runs to small fast moving rifles in water depth ranging from 0.25 to 1.5 meters. Individuals of C. polypilosus sp. nov. were collected in relative abundance where loose cherty substrates dominated shallow riffles. Faxonius compressus (Faxon, 1884) and Faxonius durelli ( Bouchard & Bouchard, 1995) co-occurred with C. polypilosus sp. nov. The morphotype was collected on 9 August 2017 by E.M. Delekta, D.A. FoltZ, T.N. Khan, Z.J. Loughman, C.G. Vopal, and B.w. williams; the holotype and allotype were collected on 21 October, 2017 by S.A. Canfield, E.M. Delekta, T.N. Khan, Z.J. Loughman, D.T. Meyer, A.M. Sykes, and C.G. Vopal.

Disposition of types. The holotype, allotype, and morphotype are deposited in the North Carolina Museum of Natural Sciences Non-Molluscan Invertebrate Collection (catalog numbers NCSM 29794, 29795, 29808, respectively). Paratypes, 1 MI and 1 F, are deposited in each of the following: the west Liberty University Astacology Collection (wLU 3011), the Ohio State Museum of Zoology ( OSUMC 10460), Carnegie Museum of Natural History ( CMNH 38824), and the Smithsonian National Museum of Natural History Invertebrate Zoology Collection ( USNM 480978, 480979)..

Range and specimens examined. Cambarus polypilosus sp. nov. appears to be a Tennessee endemic, limited to the western Highland Rim physiographic province’s Buffalo, Lower Duck, and Lower Tennessee River drainages ( Fig. 5 ). The species is associated with moderate to high gradient streams with cherty gravel and cobble substrates. Extensive sampling in adjacent areas, both the Gulf Coastal Plain and Nashville Basin, has failed to procure any Glareocola specimens (J.w. Simmons T.V.A., personal communication). we believe that C. polypilosus sp. nov. is excluded from low gradient streams with elevated amounts of silt and sand substrates, and hypothesiZe that this ecological limitation is responsible for C. polypilosus sp. nov. being a western Highland Rim endemic. Cambarus polypilosus sp. nov. appears to be present when suitable habitat exists (see next section). SiZeable populations of C. polypilosus sp. nov. have, to date, been documented in Little Richland, Richland, and white Oak Creeks in the Lower Tennessee River drainage, Blue, Hurricane, Little Blue, and Little Hurricane Creeks in the Lower Duck River drainage, and Forty Eight Creek in the Upper Buffalo River drainage.

we examined 155 C. polypilosus sp. nov. (33 IM, 21 IIM, 73 F, 28 juveniles) from a total of 14 lots from 11 streams including the type series and additional material housed in the North Carolina Museum of Natural Sciences Non-Molluscan Invertebrate Collection ( NCSM), Smithsonian National Museum of Natural History Invertebrate Zoology Collection ( USNM) , Tennessee Valley Authority Specimen Collection (TVA) , Tennessee wildlife Resources Agency Specimen Collection (TwRA), and west Liberty University Astacology Collection (wLU) from the following locations . TENNESSEE: Hickman County: (#1) Mill Creek., TVA 44-6, N 35.8736 w 87.4650. 13 IIM, 6 F, G. P. Shaffer, C.F. walton, K.D. Parr. Humphreys Co. : (#2.) Big Richland Cr. , NCSM 29805, N 36.1466 w 87.7059, 1 F, Z.J.L. & B.w.w. 9 August, 2017; TVA 44-1, Big Richland Cr. , N 36.1572 w 87.8203 , 4 June, 2008, 1 F, 1 IM, J. Thomasson & A.K. wales; TVA 44-2, N 36.1572 w 87.8203 , 11 July, 2013, 1 F, J.C. Justice, A.E. Hooper, N.L. Poppe, K.D. Parr, S.D. Stamey, J.M. Mollish. (#3.) Blue Cr. , NCSM 29806 , N 36.0626 w 87.7317, 9 August, 2017, 1 F, 5 Juv. Z.J.L. & B.w.w. (#4.) Deer Cr. , NCSM 29807, N 36.1630 w 87.7541, 9 August, 2017, 11 F, 6 IIM, 11 Juv., Z.J.L. & B.w.w. (#5.) Little Blue Cr. , N 36.0673 w 87.7289 , 17 October, 2017, Z.J.L.; CMNH 38824, 1 IM, 1 F Paratypes; NCSM 29793 Holotype; NCSM 29794 Allotype; NCSM 29795 Morphotype; NCSM 29808 20 IM, 27 F, 9 Juv.; OSU 10460, 1 IM, 1 F Paratypes; USNM 480979, 1 IM; USNM 480978 1 F Paratypes; wLU 3011, 1 IM, 1 F Paratypes. (#6.) Little Hurricane Cr. , N 36.0332 w 87.6318, NCSM 29809 , 9 August, 2017, 9 F, 5 IIM, 2 Juv., Z.J.L. & B.w.w. ; NCSM 29810 , 20 October 2017, 2 IM, 3 F, Z.J. L 2017. (#7.) Little Richland Cr. , NCSM 29811, N 36.1224 w 87.7670, 9 August, 2017, 3 IIM, Z.J.L. & B.w.w.; TVA 44- 5, N 36.1450 w 87.8653, 5 June, 2008, 1 Juv., 14 J. Thomasson. (#8.) Trace Cr. , TVA 44-3, N 36.0518 w 87.9065 , 3 June, 2008, 1 F, J.w. Simmons. (#9.) Un-named trib. , USNM 130068 , N 35.9952 w 87.7631, 9 April, 1969, 5 F, 1 IIM, 1 IM, H.H. Hobbs, Jr. (#10.) white Oak Cr. , NCSM 2 9812, N 36.2141 w 87.7072, 21 October, 2017, 1 F, Z.J.L. Houston Co.: (#11.) TVA 44-4, Hurricane Cr. , N 36.3348 w 87.9162 , 20 June, 2006, 1 F, P.R. Hollingsworth. wayne Co.:(#12.) Fortyeight Cr. , N 35.3442 w 87.6633 , NCSM 29813, 8 August, 2017. 1 F, Z.J.L. & B.w.w. 2017; TwRA 1987, 25 August, 2015, 4 F, 1 IIM, C.E. williams; TwRA 1998, 13 October, 2015, 5 IM, 2 F, C.E. williams..

Habitat and life history notes. Cambarus polypilosus sp. nov. is a component of a unique crayfish community that has adapted to the ephemeral and unstable substrates of many streams in the western Highland Rim. The substrate of most western Highland Rim streams is characteriZed by a dominance of cherty gravel and cobble—generally lacking larger components—that is prone to often-drastic movement in response to high water events. Cambarus polypilosus sp. nov. and F. compressus , the most frequently encountered co-occurring crayfishes in this area of the western Highland Rim, both exhibit morphological adaptations that allow them to coloniZe the hyporheic Zone proper. This behavior provides a mechanism by which a species may cope with the lack of boulders and the shifting nature of stream substrates in this region. The carapace of F. compressus is strongly dorsolaterally compressed, facilitating navigation into and through the interstitial spaces that C. polypilosus sp. nov. also inhabits. As such, F. compressus may represent an important competitor for C. polypilosus sp. nov., which it greatly outnumbered at all localities at which we encountered both species. Interestingly, C. polypilosus sp. nov. was typically found at substrate depths far below that of F. compressus . It is unclear if such habitat partitioning is driven by competition or other ecological factors.

Cambarus polypilosus sp. nov., like all other Glareocola species, inhabits the hyporheic Zone of ephemeral and perennial streams. Its short, stocky build facilitates utiliZation of interstitial spaces as refugia. In effect, C. polypilosus sp. nov. “bulldoZes” its way through these spaces, often to depths of 0.3 m or more, using its strongly built chelae to manipulate gravel amongst cobbles. Cambarus polypilosus sp. nov. was only found in streams with fluvial substrates largely or entirely lacking boulders and slabs. when larger substrate components were present, C. polypilosus sp. nov. could be found in shallow depressions excavated underneath, though were most often encountered in burrow networks mid-channel in the chert scree that dominates western Highland Rim streams.

when released onto cherty substrates in both field and laboratory settings, C. polypilosus sp. nov. quickly began manipulating gravel and burrowed into the substrate. In captivity, individuals have been observed moving just under the surface of the substrate, their actions given away by movement of gravel. Substrate siZe and ratio is an important ecological limiting factor for this species. Presence of C. polypilosus sp. nov. was directly associated with presence of gravel and cobbles with abundant interstitial space. The species was noticeably absent from streams where sand and silt occurred en masse. Fine substrates likely fill the interstices between cobbles and gravels that C. polypilosus sp. nov. utiliZes as refugia, and may therefore be ecologically limiting for this species. The species occurs in medium to high velocity stream habitats; it is possible that faster stream flows flush fine sediments from the interstitial spaces.

Cambarus polypilosus sp. nov. constructed shallow burrows which they appeared to defend from both conspecifics and other crayfishes. During fieldwork in October 2017 several individuals were encountered resting at burrow portals created both under boulders and in chert scree. On more than one occasion, young of the year F. compressus were observed entering C. polypilosus sp. nov. burrows, typically in response to disturbance created by sampling activity. In all instances F. compressus were quickly engaged and ushered out of the burrow by resident C. polypilosus sp. nov.

Cambarus polypilosus appears to undergo seasonal synchroniZation in molts like other cambarid crayfishes. Form I males were collected in late August, and in fall and spring (April) months. During late spring and summer (May through early August) our efforts revealed the presence of form II males only. Form I females, distinguished by noticeably wider pleons, were collected in October 2017. Females collected in the early summer months of May through June did not exhibit this condition. No females were observed with active glare glands during sampling efforts undertaken early August of 2017, whereas numerous females collected in late October 2017 had active glare glands. Ovigerous females and females carrying young have not been observed.

Conservation status. At present, C. polypilosus sp. nov. should be listed as currently stable based on the criteria of the American Fisheries Society established in Taylor et al. (2007), assigned a G4/G5 ranking using the global conservation criteria of Master (1991), and listed as least concern (LC) using the criteria of the International Union for the Conservation of Nature ( IUCN 2001). Although the species has a narrow distribution, largely restricted to the lower Duck River drainage, including the Buffalo River, and several small tributaries to the Tennessee near the mouth of the Duck River, it is typically found at low to moderate densities in habitats where it occurs. Cambarus polypilosus sp. nov. inhabits interstices in chert-laden substrate of clean, clear (silt-free) streams of the western Highland Rim. As such, habitat alteration, habitat degradation, and fluctuations in water quality may drastically and detrimentally affect the species, necessitating ongoing monitoring efforts despite current stable status. Glareocola species, as a whole, are infrequently encountered during standard aquatic surveys, resulting in the perception that these small-bodied crayfishes are rare; however, our efforts suggest that the perceived rarity of these species may primarily be an artifact of sampling method.

Crayfish associates. Cambarus polypilosus sp. nov. has been collected with Faxonius durelli , Faxonius compressus , Cambarus gentryi Hobbs, 1970 , and Cambarus striatus (Hay, 1902) .

Variation. The rostrum of C. polypilosus sp. nov. typically is narrow with thickened margins that gradually decrease in breadth anteriorly from the base to the acumen. The acumen is acuminate. In rare cases, the rostrum is wide at its base, reducing the overall narrow appearance; however, the rostrum of C. polypilosus sp. nov. never appears parallel throughout its length, and the acumen is always acuminate. Thickness of the rostrum margin appears to vary by latitude, with individuals from northern parts of the range possessing the thickest margins. Individual variation occurs in the shape of the cephalomedian lobe of its epistome. This structure typically is asymmetrical in this species, with the one cephalolateral margin distinctly bulging anterolaterally. This bulge forms a right angle in the right cephalolateral margin of the holotype, but most frequently is less acute. In other specimens, the epistomal bulge occurs on the left side. Based on specimens examined, the bulge appears to always be present.

Cambarus polypilosus sp. nov. displays ontogenetic differences in coloration, with juveniles appearing brighter than adults. In addition, the distal part of the chela often appears reddish in juveniles, but in adults is not distinct from proximal regions of the propodus and dactyl. The dorsal and lateral coloration of adult C. polypilosus sp. nov. typically consists of varying shades of browns. Occasionally specimens exhibit base coloration of muted to bright yellows ( Fig. 4 ). The prevalence of this color variant appears uniform throughout the sampled range.

Relationships and comparisons. Cambarus polypilosus sp. nov. is most similar, within the genus, to the three members of Glareocola given its small siZe, truncated chelae, and its extreme setiferous state, but can be distinguished from each of these described species by a combination of characters including body siZe, gonopod morphology, coloration, spination, and setation. The gonopod morphology of C. polypilosus sp. nov. most closely resembles that of C. friaufi . The form I male gonopod of both species possesses a caudal knob and lacks a subapical notch, and is generally indistinguishable; however, C. polypilosus sp. nov. differs from C. friaufi in several morphometric ratios, spination, rostrum morphology, and color pattern.

Cambarus polypilosus sp. nov. exhibits a higher pooled-demographic palm length/width ratio (? = 94.9%, n = 27, σ = 9.4%) and lower pooled-demographic rostrum width/length ratio (? = 46.5%, n = 27, σ = 4.6%) than the same pooled-demographic ratios for C. friaufi (? = 84.8%, n = 30, σ = 4.6%;? = 66.6%, n = 30, σ = 8.6%). Variation in these ratios is decreased when comparing form I male C. polypilosus (palm length/palm width ratio:? = 92.7%, n = 9, σ = 2.8%; rostrum width/rostrum length:? = 46.7%, n = 9, σ = 4.5%) to form I male C. friaufi (palm length/palm width ratio:? = 83.9%, n = 9, σ = 2.5%; rostrum width/rostrum length:? = 64.9%, n = 9, σ = 9.4%), though it should be noted a small samples siZe was used to calculate these ratios. The ventral lateral margin of the merus has between 3–6 (? = 4.0, n = 27, σ = 0.9) venterolateral spines in C. polypilosus sp. nov.; C. friaufi lacks these spines entirely. Both C. polypilosus and C. friaufi possess distal merus and lateral merus spines ( Fig. 6 ).

The rostrum of C. polypilosus sp. nov. is acuminate with margins thickened along their entire length; C. friaufi has a broader rostrum with thickened margins that abruptly terminate into thin margins posterior to the acumen ( Fig. 7 ). The coloration of C. polypilosus sp. nov. is dominated by shades of light brown and tan. The dominant coloration of C. friaufi includes greens, browns, and purples. Cambarus friaufi also possesses a black saddle along the posterior margin of the carapace (100 % of living animals examined; n = 56 specimens from 6 sites), a color pattern that is absent in C. polypilosus sp. nov. (100 % of living specimens examined; n = 72 specimens from 9 sites).

The general appearance, e.g., coloration and body siZe, of C. polypilosus sp. nov. is most similar to C. brachydactylus , with both typically exhibiting various shades of brown and both possessing ventrolateral merus spines. These two species are readily distinguished from each other by both gonopod morphology and the arrangement of punctations within the areola. The form I male gonopod of C. brachydactylus lacks a caudal knob, whereas the form I male gonopod of C. polypilosus sp. nov. possesses a caudal knob. The areola in both C. polypilosus sp. nov. and C. brachydactylus is wide; however, in C. polypilosus sp. nov. the areola exhibits punctations along both margins and a single disorganiZed row of punctations, whereas in C. brachydactylus , the areola is densely punctated in an unorganiZed fashion.

Cambarus polypilosus sp. nov. differs from C. williami in overall body siZe and gonopod morphology, and coloration. Cambarus polypilosus sp. nov. is consistently larger than C. williami . Further, the form I male gonopod of Cambarus polypilosus sp. nov. is characteriZed by presence of a caudal knob and both central and mesial process bent 90° to the shaft, whereas in C. williami the caudal knob is absent and the terminal elements are straight to gently recurved. Cambarus polypilosus coloration is dominated by various shades of brown; C. williami coloration consists of blacks, green-browns, and blue-greens.

Common name. The Hillbilly Hairy Crayfish.

Etymology. The species epithet polypilosus is derived from a combination of the Greek “poly-” meaning many and Latin “pilosus” meaning covered in hair, referring to the overall setiferous appearance of members of the species.

Figures

FIGURE 3. Cambarus polypilosussp. nov. form I male, Little Hurricane Creek, Humphreys County, Tennessee.

FIGURE 4. Cambarus polypilosussp. nov. yellow phase female, Little Blue Creek, Humphreys County,Tennessee.

FIGURE 6. Merus morphology in ventral view of Cambarus friaufi (A.) and Cambarus polypilosus sp. nov. (B.). Yellow arrow pointingat large distalmerus spine shared between both species.Small grey arrowspointing at small ventrolateral merus spines possessed by C. polypilosus sp. nov. Specimens depicted not from the typeseries.

FIGURE 7. Rostrum morphology of Cambarus friaufi (A.) and Cambarus polypilosus sp. nov. (B.). Specimens depicted not from the type series.

FIGURE1. Multi-Dimensional Scaling (MDS) ordination plot showing morphometric variation among Cambarus polypilosus sp. nov. and Cambarus friaufi. Each number represents an individual specimen and the relative distance between two points represents the similarity/dissimilarity.

FIGURE2. Cambaruspolypilosus sp.nov. (A.)Lateral view of carapace; (B.)Lateral and(C.) mesial view of form I gonopod; (D.) Lateral and (E.) mesial view of form II gonopod; (F.) Annulus ventralis; (G.) Dorsal view of carapace; (H.) Dorsal view of right carpus and chelae; (I.) epistome.A–C and G–I from holotype; F from allotype; D–E from morphotype.

FIGURE5. Map showingthe distribution of Cambaruspolypilosus sp. nov. in theBuffalo,Lower Duck, andLower Tennessee river basins. Red circles indicate sampling localitieswhere the species was detected; The red square indicates type location.