Cambarus burchfielae Perkins, Williams & Russ, 2023

Perkins, Michael A., Williams, Bronwyn W. & Russ, William T., 2023, Integrative taxonomy reveals two new narrowly-endemic crayfish species (Decapoda: Cambaridae) from the Yadkin River Basin in western North Carolina, USA, Zootaxa 5270 (2), pp. 207-230 : 218-225

Cambarus burchfielae Perkins, Williams & Russ , sp. nov.

Figures 7–9 , Table 4

Diagnosis. Body and eyes pigmented. Base of rostrum broad, mid and anterior portions subparallel, weakly excavated, ventrally deflected, margins thickened to acumen, without spines or tubercles; median carina not present. Acumen well-defined, with prominent terminal, dorsally-deflected, spiniform tubercle. Rostrum 1.00–1.58 (x = 1.24, n = 25) times long as wide.

Areola 2.26–4.00 (x = 3.07, n = 25) times long as wide, with 4–5 punctations through narrowest point. Carapace compressed dorsoventrally, subovate in cross section; lateral area of branchiostegal region heavily tuberculate; typically 1 or more weakly-defined cervical tubercles, rarely spiniform. Branchiostegal spine absent or greatly reduced. Postorbital ridge well-developed, not terminating in tubercle or spine. Suborbital angle moderately acute, not terminating in tubercle or spine.

Mesial palm of chelae with one row of 5–7 typically weakly-developed cristiform tubercles (n=22). Subpalmar tubercles usually absent, but at least one reduced subpalmar tubercle present in several individuals examined (44.4%, n=27); some specimens rarely with 2 tubercles (7.4%). Opposable margin of propodus typically with 6–8 well-developed denticles, roughly equivalent in size, terminating in pronounced, sometimes pointed terminal tubercle; denticles extending an average of 52.2% of distal length. Opposable margin of dactyl with 5–7 denticles, roughly equivalent but tapering in size distally, denticles extending an average of 41.6% distal length. Dactyl typically smooth along dorsal surface, but rarely with 1–3 weakly-pronounced tubercles. Palm length to dactyl length ratio averaging 0.51. Sharp corneous tip present on dactyl and fixed finger of propodus. Carpus typically with one large, well-developed spine on mesial margin, with one reduced tubercle towards posterior margin of the carpus.

First pleopod of form I male with long terminal elements; central projection not tapered, curved approximately 90° to shaft of gonopod, with conspicuous subapical notch, length approximately equal to the marginal terminus of the mesial process; mesial process curved 90° to main shaft, conically shaped at base, tapering to a rounded terminus projecting beyond the margin of the main shaft, directed caudolaterally. Form II male central projection rounded, curved 90° to mesial process, terminal margin extending beyond the mesial process terminus; mesial process conical, directed caudolaterally, tapering to a rounded terminus with small laterally-deflected tip, terminal length greater than margin of shaft. Hooks on ischium of third pereiopods in from I and II males. Female annulus ventralis asymmetrical and appearing sclerotized caudally; distinct “S”-shaped bend, terminating in caudal portion; cephalic portion consists of median trough leading to central fossa, not sclerotized.

Holotypic Male, Form I ( Fig. 7–8 ; Table 4 ). Body somewhat compressed dorsoventrally; carapace posterior to cervical groove wider than abdomen. Carapace width greater than carapace depth at caudodorsal margin of cervical groove. Total carapace length 45.4, PCL 38.6. Areola 3.9 times longer than wide, somewhat narrow with 4 punctations across the narrowest section. Rostrum excavated; margins moderately thickened, subparallel and tapering to acumen. Rostrum 1.1 times longer than width at base, moderately truncated, acumen well-defined and terminating in deflected corneous tip; floor of rostrum with numerous punctations. Postorbital ridge well-developed but lacking well-defined terminal tubercle. Suborbital angle acute, lacking terminal tubercle. Single tubercle present at lateral margin of cervical groove. Orbital, branchiostegal, and mandibular regions of carapace with well-developed tubercles; greatest tubercle density in hepatic region. Branchiostegal spine present but strongly reduced. Abdomen subequal in length to carapace, 1.6 times longer than wide, pleura rounded cephaloventrally and angled caudoventrally. Lateral margin of terga weakly angulate, lateral margin of second pleuron with deep furrow. Cephalic section of telson with 2 conspicuous spines in each caudolateral corner. Proximal podomere of uropod with distal spine on mesial lobe. Mesial ramus of uropod with median ridge tapering distally, terminating in median spine not extending beyond margin of ramus; laterodistal spine present but reduced. Distal margin of proximal segment of lateral ramus of right uropod with 1 large fixed lateral spine, 1 reduced movable spine, and numerous small immovable spines. Cephalomedian lobe of epistome subtriangular, thin, lateral margins weakly inflated, tapering medially to conspicuous anterior terminus; zygoma moderately arched; cephalolateral margins thickened, rounded at junction with endostyle; body of epistome possessing prominent median fovea. Antennal scale broadest proximally, setiferous along mesial margin, lateral margin thickened and terminating in large spine. Right antennal scale 2.5 times longer than wide. Antennae extending just beyond posterior margin of lateral rami when adpressed. All following descriptions from right chela. Mesial surface with one row of 6 weakly-defined tubercles. Palm length 78.9% palm width. Dorsal longitudinal ridge of dactyl smooth, dactyl terminating in corneous spine. Weakly pronounced dorsomedian ridge on fixed finger of propodus; scattered and numerous punctations throughout, absent of elongated setae; terminating in corneous tip. Opposable margin of propodus from base consisting of 4 well-defined tubercles, one smaller tubercle, ending in sharply pointed tubercle. Opposable margin of dactyl from base consisting of 4 well-defined tubercles and 2 smaller tubercles tapering in size to terminus. Subpalmar tubercle absent. Carpus with prominent dorsal furrow, surface with scattered punctuations, mesial margin with single large procurved spine. Distodorsal surface of merus with 9 spines and spiniform tubercles, ventromesial ridge with 1 weakly-developed spiniform tubercle, ventrolateral ridge with 2 small spines. Well-developed hooks on ischium of third pereiopods. Form I gonopod as described in Diagnosis.

Allotypic Female ( Fig. 7 & 9 , Table 4 ). Differing from holotype in the following respects: TCL 42.3 mm, PCL 36.3 mm; areola 3.3 times longer than wide; rostrum 1.2 times longer than width at base; custer of 5 tubercles present at lateral margin of cervical groove; areola with 5 punctations across narrowest point; abdomen 1.5 times longer than wide. Right chela regenerated, all following descriptions from left chela: mesial margin with one row of 6 weakly-developed tubercles; palm length 80.1% palm width; single small subpalmar tubercle present; mesial margin of carpus with well-developed large procurved spine and proximal spiniform tubercle. Antennae extending to fifth terga when adpressed. Antennal scale 2.4 times longer than wide. Specimen lacks all male secondary sexual traits. Annulus ventralis as described in Diagnosis. Specimen in glair.

Morphotypic Male, Form II ( Fig. 7 , Table 4 ). Differing from the holotype in the following respects: TCL 31.0 mm, PCL 26.0; areola 3.3 times longer than wide; rostrum 1.1 times longer than wide at base; abdomen 1.7 times longer than wide. Right chela regenerated, all following descriptions from left chela: mesial margin with one row of 6 weakly-developed tubercles; palm length 67.3% palm width; two small subpalmar tubercles present. Antennae extending to posterior margin of second terga when adpressed. Antennal scale 2.2 times longer than wide. Hooks on ischium of third pereiopods weekly developed. Form II gonopod as described in Diagnosis.

Size. Form I male (n = 8) TCL ranging in size from 31.9 mm to 45.4 mm (x = 38.1, SD = 4.34). Form II male (n = 7) TCL ranging in size from 31.1 mm to 40.0 mm (x = 35.2, SD = 3.01). Female (n = 10) TCL ranging 23.2 mm to 42.3 mm (x = 37.3, SD = 5.48). The largest specimen observed was the holotypic from I male measuring 40.6 mm TCL.

Color Notes. Cambarus burchfielae ( Fig. 8 ) carapace ground color mottled, brown to dark orange-brown. Mandibular adductor scars mottled, brown. Sides of carapace darkened, often with heavy mottling. Hepatic region mottled brown to tan, punctuated with tan tubercles. Rostrum ground color brown to olivaceous, margins of acumen rusty-brown to tan. Lateral margin of antennal scale brown, body light brown to cream. Antennae and antennules brown to olivaceous. Dorsal surface of chelae mottled, orange-brown to olivaceous, tubercles on mesial margin and not conspicuous, same as surface color of the chelae; ventral surface of chelae tan to cream. Denticles on opposable surfaces of chelae cream-colored. Dorsal surface of carpus mottled olivaceous and orange-brown, carpus spine and tubercles cream-colored. Ventral surface of carpus tan to cream. Dorsal surface of merus brown to olive, ventral surface tan to cream, tubercles cream-colored. Dorsal surface of abdomen ground color mottled, deeper orange-brown to olivaceous, posterior margins of terga mottled, pleura olivaceous to orange brown. Ventral surface of abdomen light brown to tan, swimmerets tan. Dorsal ridge of form I gonopod amber, body of gonopod, mesial process, shaft cream-colored to tan. Form II process and shaft cream-colored or tan. Annulus ventralis cream-colored to brown.

Type Locality. Fall Creek, adjacent to SR 1301 (Fall Creek Road), approximately 1.5 km N of the confluence with the South Prong Lewis Fork (N 36.2086, W 81.4288), Wilkes County, North Carolina. This section of Fall Creek is approximately 495 m elevation above sea level, buffered by a secondary forest of intact hardwoods and high canopy cover, approximately 5 m width, 0.25 m in depth, with a clean heterogenous stream bottom composed primarily of boulder, cobble, and gravel; secondarily composed of bedrock, sand, and woody debris/organic material. The holotype was collected 19 August 2019 ; the allotype and morphotype were collected 17 April 2019.

Disposition of types. The holotype ( NCSM 90219 ), allotype ( NCSM 90220 ), morphotype ( NCSM 90221 ), and three paratypes ( NCSM 90225 , 91098 ) are deposited in the North Carolina Museum of Natural Sciences Non-molluscan Invertebrates Collection. Two additional paratypes, 1 MI and 1 F, are deposited in the Smithsonian National Museum of Natural History Invertebrate Zoology Collection , USNM XXXXXXX and XXXXXXX, respectively.

Range and specimens examined. NORTH CAROLINA, Wilkes County: 1 ) NCSM 90220 Allotype — Fall Creek along SR 1301 Falls Creek Rd. , N 36.2096 W 81.4288, 1 F, 2 April 2019 , W. T. Russ, M.A. Perkins, M.A. Burchfiel; 2 ) NCSM 90221 Morphotype —Fall Creek along SR 1301 Falls Creek Rd. , N 36.2096 W 81.4288, 1 MII, 2 April 2019 , W. T. Russ, M.A. Perkins, M.A. Burchfiel; 3 ) NCSM 90240 — Fall Creek along SR 1301 Falls Creek Rd. , N 36.2096 W 81.4288, 1 MI, 2 April 2019 , W. T. Russ, M.A. Perkins, M.A. Burchfiel; 4 ) NCSM 90228 — North Prong Lewis Fork at Parsonville Rd. bridge immediately upstream of confluence with Little Fork Creek , N 36.2092 W 81.3453, 1 MI, 2 April 2019 , W. T. Russ, M.A. Perkins, M.A. Burchfiel; 5 ) NCSM 90225 Paratypes — Pumpkin Run at SR 1303 bridge Pumpkin Run Rd. , N 36.2032 W 81.3836. 1 MI, 1 MII, 27 August 2019 , W. T. Russ, M.A. Perkins, M.A. Burchfiel; 6 ) NCSM 90239 — Fletcher Creek at Shady Walk Lane bridge approximately 100 m upstream of confluence with South Prong Lewis Fork , N 36.1938 W 81.4134, 1 MI, 1 MII, 27 August 2019 , W. T. Russ, M.A. Perkins, M.A. Burchfiel; 7 ) NCSM 90230 — South Prong Lewis Fork at SR 1389 bridge, N 36.2071 W 81.4476, 2 F, 27 August 2019 , W. T. Russ, M.A. Perkins, M.A. Burchfiel; 8 ) NCSM 90226 — Fall Creek along SR 1301 Fall Creek Rd. , N 36.2096 W 81.4288, 1 MII, 27 August 2019 , W. T. Russ, M.A. Perkins, M.A. Burchfiel; 9 ) NCSM 90219 Holotype — Fall Creek along SR 1301 Falls Creek Rd. , N 36.2096 W 81.4288, 1 MI, 27 August 2019 , W. T. Russ, M.A. Perkins, M.A. Burchfiel; 10 ) NCSM 90227 — Purlear Creek at SR 1317 bridge New Hope Rd. , N 36.1927 W 81.2937, 1 F, 14 November 2019 , M.A. Perkins & M.A. Burchfiel; 11) USNM XXXXXXX — North Prong Lewis Fork at SR 1363 bridge Big Ivy Rd. , N 36.2613 W 81.3952, 1 M1, 1 F, 14 November 2019 , M.A. Perkins & M.A. Burchfiel; 12) NCSM 91096 — Fall Creek along SR 1301 Falls Creek Rd. , N 36.2096 W 81.4288, 1 F, 15 December 2020 , W. T. Russ & M.A. Perkins; 13 ) NCSM 91097 — Fall Creek along SR 1301 Falls Creek Rd. , N 36.2096 W 81.4288, 1 F, 15 December 2020 , W. T. Russ & M.A. Perkins; 14 ) NCSM 91098 Paratype — Fall Creek along SR 1301 Falls Creek Rd. , N 36.2096 W 81.4288, 1 F, 15 December 2020 , W. T. Russ & M.A. Perkins; 15 ) NCSM 91095 — Fall Creek along SR 1301 Falls Creek Rd. , N 36.2096 W 81.4288, 1 MI, 15 December 2020 , W. T. Russ & M.A. Perkins; 16 ) NCSM 91099 — Fall Creek along SR 1301 Falls Creek Rd. , N 36.2096 W 81.4288, 1 MII, 15 December 2020 , W. T. Russ & M.A. Perkins; 17 ) NCSM 90245 — North Prong Lewis Fork at SR 1300 bridge Parsonville Rd. , N 36.2131 W 81.3580, 1 MI, 1 F, 15 December 2020 , W. T. Russ & M.A. Perkins; 18 ) NCSM 91101 — North Prong Lewis Fork at SR 1363 bridge Big Ivy Rd. , N 36.2613 W 81.3952, 1 M1, 1 MII, 22 December 2020 , W. T. Russ & M.A. Perkins; 19 ) NCSM 91102 — North Prong Lewis Fork at SR 1363 bridge Big Ivy Rd. , N 36.2613 W 81.3952, 1 MII, 1 F, 22 December 2020 , W. T. Russ & M.A. Perkins

Conservation status. Cambarus burchfielae is locally common but narrowly distributed in the headwaters of two watersheds in western North Carolina with an estimated current extent of approximately 145 km 2. Populations are distributed in the mainstem and tributaries of both the South and North Prong Lewis Fork watersheds, but while migration between populations is theoretically unobstructed by instream barriers, the prevalence of a congener, C. species C, around the confluence may preclude C. burchfielae from moving freely between the watersheds. The estimated population size for C. burchfielae is currently unknown. Threats to the species have not been fully assessed but include habitat degradation and diminished water quality from agriculture and silviculture in some areas of the watershed; much of the watershed is currently forested. Based primarily on the species’ currently known 2 disjunct populations with a narrow distribution, we suggest that the species be assigned the status of G2/S2 (Imperiled) based on NatureServe criteria (NatureServe 2020) and Vulnerable (VU) based on International Union for the Conservation of Nature criteria ( IUCN 2001; B2 a,b i–iv).

Variation. A small number of specimens examined possess a few (1–3) weakly-pronounced tubercles on the dorsal surface of the dactyl, a character superficially similar to C. lapidosus , C. species C and Cambarus aff. robustus . Juveniles and sub-adults lack well-developed meristic characters therefore identification of young individuals of this species can be difficult. Members of this species exhibit sexual dimorphism in reproductive structures. We have not observed any obvious geographic variation in this species.

Life history. Collections of C. burchfielae have been limited to the months of April, August, November, and December. First and second form males have been observed in April, August, November, and December. Females in glare have been collected in April and December. Young-of-year have not been observed. The species appears to prefer cool, clean 2 nd to 3 rd order streams and has been collected almost exclusively from under large cobbles (approx. 25 cm in length) to small boulders (approx. 100 cm in length) in moderately deep riffles or runs (0.1 m to 0.5 m) with moderate to high flow and high canopy cover.

Crayfish associates. Several native stream-dwelling associate crayfish species occur with C. burchfielae including C. johni , C. aff. longulus , and C. species C. Cambarus aff. dubius , a primary burrower, was observed in burrows along stream banks.

Relationships and comparisons. Cambarus burchfielae is morphologically similar to several described species and yet-undiagnosed members of the genus Cambarus in Atlantic Slope and interior basin streams. Cambarus burchfielae was previously subsumed within C. species C complex, which occurs throughout Atlantic Slope drainages in the Mountain and Piedmont ecoregions of NC. Cambarus species C from the upper Yadkin and adjacent Catawba basins in NC can be differentiated from C. burchfielae by the presence of conspicuous cervical spines, two rows of well-pronounced cristiform tubercles on the mesial margin of the palm of the chelae, a longer and more acuminate rostrum, and a wider areola (6–8 punctations across). The lower reaches and small tributaries of the South and North Prong Lewis Fork watersheds are dominated by C. species C from the proximity of their confluence and upstream approximately 15 km and 10 km, respectively; it is important to note the taxa co-occur in some reaches.

Despite its historic affiliation with C. species C, C. burchfielae is more morphologically and genetically similar to undiagnosed forms within the C. robustus species complex, which occur in the New and Watauga River basins. Specimens of C. aff. robustus from the New and Watauga basins examined during this study possess two rows of well-pronounced cristiform tubercles on the mesial margin of the palm of the chelae and a wider areola (8–10 punctations across); C. burchfielae typically has one row of weakly-developed tubercles on the mesial margin of the palm and a more narrow areola (4–5 punctations). Cambarus burchfielae is not known to occur in any interior basin streams, and is therefore geographically isolated from other putative taxa currently subsumed within the C. robustus species complex.

Cambarus burchfielae is genetically and morphologically most similar to C. lapidosus , described above. These species are easily morphologically distinguished from each other despite their genetic and geographic affinities. Cambarus lapidosus possesses a double row of well-developed cristiform tubercles on the mesial margin of the chelae, conspicuous tubercles on the dorsal surface of the dactyl, a wider and typically more-punctate areola (5–7 punctations), and a rusty pigment patch on the dorsal surface of the carapace immediately anterior of the abdomen also common to the congeners C. species C and C. johni . These species can also be differentiated by subtle differences in gonopod morphology (see Figs. 3 & 7 ); the central projection of the form I gonopod of C. lapidosus is longer and more strongly-curved than C. burchfielae . Conversely, the central projection of the form II gonopod of C. burchfielae extends beyond the margin of the mesial process whereas the processes are approximately equal in length in C. lapidosus .

Cambarus burchfielae is easily distinguished from other co-occurring species in the upper Yadkin basin. Cambarus aff. longulus is a small species easily characterized by conspicuous tufts of setae at the base of the opposable margin of the propodus and a narrow rostrum with an elongated acumen. Cambarus johni possesses a wider and more-heavily punctate areola (>10 punctations), conspicuous abdominal stripes, a much wider zygoma, and smaller chelae with an enlarged first denticle on the opposable margin of the dactyl.

Etymology. We chose the species epithet “ burchfielae ” to honor Morgan Aylett Burchfiel, an avid young malacologist and close friend of the authors. Morgan’s courage, enthusiasm, and perseverance through many challenges continues to be an inspiration.

Common name. We propose Falls Crayfish as the common name for C. burchfielae in reference to the type locality, Falls Creek in Wilkes County, NC.

Figures

FIGURE 3. Cambarus lapidosus, new species. (A.) Lateral view of carapace; (B.) dorsal view of carapace; (C.) right antennal scale; (D.) dorsal view of carpus and chela; (E.) epistome; (F.) lateral and (G.) mesial view of form I gonopod; (H.) lateral and (I.) mesial view of form II gonopod; (J.) annulus ventralis.A–E, F–G from holotype; H–I from morphotype; J from allotype.

FIGURE 7. Cambarus burchfielae, new species. (A.) Lateral view of carapace; (B.) dorsal view of carapace; (C.) right antennal scale; (D.) dorsal view of carpus and chela; (E.) epistome; (F.) lateral and (G.) mesial view of form I gonopod; (H.) lateral and (I.) mesial view of form II gonopod; (J.) annulus ventralis.A–E, F–G from holotype; H–I from morphotype; J from allotype.

FIGURE 8. Cambarus burchfielae, holotype (90219) in life (photo credit: Michael A. Perkins, NCWRC).

FIGURE 9. Cambarus burchfielae, (left) second form male morphotype (NCSM 90221) in life, North Prong Lewis Fork, Wilkes County, NC; (right) female allotype (NCSM 90220) in life from the type locality, Fall Creek, Wilkes County, NC; (photo credit: Michael A. Perkins, NCWRC).