Cambarus lapidosus 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 : 211-218

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

Figures 3–5 , Table 3

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 1.01–1.44 (x = 1.21, n=26) times long as wide.

Areola 1.2–3.7 (x = 2.73, n=26) times long as wide, with 5–7 punctations through narrowest point. Carapace compressed dorsoventrally, subovate in cross section; lateral area of branchiostegal region heavily tuberculate; 1–4 well-defined cervical tubercles, rarely spiniform. Branchiostegal spine present but greatly reduced. Postorbital ridge well-developed, not terminating in tubercle or spine. Suborbital angle strongly acute, not terminating in tubercle or spine.

Mesial palm of chelae with two prominent rows of well-developed cristiform tubercles; both rows with 5–8 tubercles. The majority of specimens measured (84%, n=21) possess one subpalmar tubercle; 4% (n=1) possess 2 subpalmar tubercles, and 12% (n=3) had none. Opposable margin of propodus typically with 5–7 well-developed denticles, from base consisting of 3–4 tubercles, 2–3 reduced tubercles, terminating in sharply pointed fourth tubercle; denticles extending an average of 73.2% of distal length. Opposable margin of dactyl with 5–8 denticles, from base consisting of 4–5 tubercles, tapering to 2–3 reduced tubercles; denticles extending an average of 58.0% distal length. Dactyl with 5–9 tubercles along dorsal surface, tapering in count and prominence towards terminus. Palm length to dactyl length ratio averaging 0.69. Sharp corneous tips present on dactyl and fixed finger of propodus. Carpus with one large well-developed spine on mesial margin, with one additional spiniform tubercle towards posterior margin of carpus, occasionally expressed as well-developed spine in some individuals (31%, n=23).

First pleopod of form I male with long terminal elements; central projection not tapered, curved greater than 90° to shaft of gonopod, with conspicuous subapical notch, length extending greater than the marginal terminus of the mesial process; mesial process recurved> 90° to main shaft, conically-shaped at base, tapering to a rounded terminus projecting beyond margin of main shaft, directed caudolaterally. Form II male central projection rounded, curved 90° to mesial process, approximately equal in length; mesial process conical, tapering to a rounded terminus, directed caudolaterally, terminal length greater than margin of shaft. Hooks on ischium of third pereiopods in form 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. 3-4 ; Table 3 ). 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 49.7 mm, PCL 42.1 mm. Areola 2.6 times longer than wide, moderately broad with 6 punctations across the narrowest section. Rostrum excavated; margins moderately thickened, subparallel and tapering at acumen. Rostrum 1.3 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. Cluster of 4 tubercles 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 reduced. Abdomen subequal in length to carapace, 1.7 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 absent. 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 2.1 times longer than wide. Antennae extending to anterior margin of rami when adpressed. All following descriptions from right chela: mesial surface with two rows of 7 well-defined tubercles; palm length 69.7% palm width; dorsal longitudinal ridge of dactyl with 12 scattered well-defined tubercles, dactyl terminating in corneous spine; moderately 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 5 well-defined tubercles, one smaller tubercle, ending in sharply pointed tubercle; opposable margin of dactyl from base consisting of 4 well-defined tubercles and 4 smaller tubercles tapering in size to terminus; small subpalmar tubercle absent on right chelae but present on left chelae; carpus with prominent dorsal furrow, surface with scattered punctuations, mesial margin with large procurved spine and reduced anterior proximal spine; distodorsal surface of merus with 14 spines and spiniform tubercles, ventromesial ridge with 2 well-developed spiniform tubercles, ventrolateral ridge with 4 small spines. Well-developed hooks on ischium of third pereiopods. Form I gonopod as described in Diagnosis.

Allotypic Female ( Fig. 3 , Table 3 ). Differing from holotype in the following respects: carapace damaged with dorsolongitudinal crack; TCL 32.7 mm, PCL 26.6 mm; areola 2.4 times longer than wide; rostrum length and width approximately equal at base; abdomen 1.5 times longer than wide. All following descriptions from right chela; mesial margin with one row of 7 well-developed tubercles and a second row of 6 well-developed tubercles; palm length 75% palm width; single small subpalmar tubercle present on both chelae. Antennae extending to fourth terga when adpressed. Antennal scale 1.7 times longer than wide. Specimen lacks all male secondary sexual traits. Annulus ventralis as described in Diagnosis.

Morphotypic Male, Form II ( Fig. 3 , Table 3 ). Differing from the holotype in the following respects: TCL 32.7 mm, PCL 26.6 mm; areola 2.7 times longer than wide, rostrum 1.1 times longer than wide at base; abdomen 1.7 times longer than wide. All following descriptions from right chela: mesial margin with one row of 7 well-developed tubercles and a second row of 8 well-developed tubercles; palm length 68% palm width; single reduced subpalmar tubercle present. Antennae extending to posterior margin of second terga when adpressed. Antennal scale 1.9 times longer than wide. Hooks on ischium of third pereiopods weekly developed. Form II gonopod as described in Diagnosis.

Size. Form I male (n = 9) TCL ranging in size from 37.9 mm to 49.7 mm (x= 40.3, SD = 3.76). Form II male (n = 7) TCL ranging in size from 31.4 mm to 44.2 mm (x = 36.2, SD = 4.81). Female (n = 10) TCL ranging 25.7 mm to 43.2 mm (x = 35.3, SD = 6.22). The largest specimen observed was the holotypic form I male measuring 49.7 mm TCL.

Color Notes. Cambarus lapidosus ( Fig. 4–5 ) carapace ground color mottled, olivaceous to brown. Cephalic portion of carapace immediately anterior to cervical groove dark, forming narrow saddle; mandibular adductor scars mottled, light brown to olivaceous. Posterior portion of carapace, immediately anterior to abdomen, with rust-colored dorsal patch; sides of carapace darkened with heavy mottling. Hepatic region olive, punctuated with cream-colored tubercles. Rostrum ground color olive, margins of acumen ochre to tan. Lateral margin of antennal scale olive to brown, body light brown to cream. Antennae and antennules olive to brown. Dorsal surface of chelae mottled, olive to brown, tubercles on mesial margin and surface of dactyl cream-colored; ventral surface of chelae cream. Denticles on opposable surfaces of chelae cream-colored. Dorsal surface of carpus olivaceous, carpus spine and tubercles cream-colored. Ventral surface of carpus tan to cream. Dorsal surface of merus olive to brown, ventral surface tan to cream, tubercles cream-colored. Dorsal surface of abdomen ground color mottled, deeper olive to brown, posterior margins of terga light brown to tan, pleura olivaceous. Ventral surface of abdomen olive to light brown, swimmerets brown to 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. Juvenile coloration is similar to that observed in adults.

Type Locality. Stony Fork, in the vicinity of the SR 1167 (Mt. Zion Road) bridge crossing, approximately 8 km SW of Laxon and 1 km upstream of the Flowers Branch confluence (N 36.1949, W 81.4660), Watauga County, North Carolina ( Fig. 6 ). This section of Stony Fork is approximately 645 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 gravel, cobble, and boulder; secondarily composed of bedrock, sand, and woody debris/organic material. The holotype was collected 29 October 2019 , and the allotype and morphotype were collected 6 November 2017.

Disposition of types. The holotype, allotype, morphotype, and four paratypes are deposited in the North Carolina Museum of Natural Sciences Non-molluscan Invertebrates Collection, catalog numbers NCSM 90222 , 90223 , 90224 , and 90241, respectively. 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, Watauga County: 1 ) NCSM 90236 — Stony Fork at SR 1500 bridge, Mt. Zion Rd. , N 36.1949 W 81.4660, 1 F, 29 October 2019, M.A. Perkins, W . T. Russ & W.J. Russ; 2 ) NCSM 90222 Holotype — Stony Fork at SR 1500 bridge, Mt. Zion Rd. , N 36.1949 W 81.4660, 1 MI, 29 October 2019, M.A. Perkins, W . T. Russ & W.J. Russ; 3 ) NCSM 90241 Paratypes — Orchard Creek at SR 1362 Bridge, Orchard Creek Rd. , N 36.2157 W 81.4735, 1 MI, 1 MII, 2 F, 19 November 2020, M.A. Perkins, W . T. Russ & W.J. Russ; 4 ) NCSM 90242 — Orchard Creek at SR 1362 Bridge, Orchard Creek Rd. , N 36.2157 W 81.4735, 1 M juv; 19 November 2020, M.A. Perkins, W . T. Russ & W.J. Russ; 5 ) NCSM 90237 Stony Fork at SR 1505 bridge, Stony Fork Rd. , N 36.2109 W 81.4819, 2 MI, 1 MII, 1 F, 1 F juv; 19 November 2020, M.A. Perkins, W . T. Russ & W.J. Russ; 6 ) NCSM 90238 — Flowers Branch at SR 1501 bridge, Flowers Branch Rd. , N 36.1939 W 81.4754, 1 MI, 1 MII, 1 F, 19 November 2020, M.A. Perkins, W . T. Russ & W.J. Russ; 7 ) USNM XXXXXXX — Wildcat Creek at SR 1505 bridge, Wildcat Rd. , N 36.1992 W 81.5013, 1 MI, 1 F, 19 November 2020, M.A. Perkins, W . T. Russ & W.J. Russ; 8 ) NCSM 90223 Allotype — Stony Fork at SR 1500 Bridge, Mt. Zion Church Rd. approximately 50 m upstream of the Flowers Branch confluence, N 36.1895 W 81.4661, 1 F, B.W. Williams, M.A. Perkins, S.G. Anderson; 9 ) NCSM 90224 Morphotype— Stony Fork at SR 1500 Bridge, Mt. Zion Church Rd. approximately 50 m upstream of the Flowers Branch confluence, N 36.1895 W 81.4661, 1 MII, B.W. Williams, M.A. Perkins, S.G. Anderson; 10 ) NCSM 90244 — Stony Fork at SR 1500 Bridge, Mt. Zion Church Rd. approximately 50 m upstream of the Flowers Branch confluence, N 36.1895 W 81.4661, 1 MI, B.W. Williams, M.A. Perkins, S.G. Anderson; 11 ) NCSM 3314 — Stony Fork at intersection of Mt. Zion Rd (SR 1500) and Hayes Welborn Rd (SR 1505), 2 F, 2 M juv, 23 July 1996, L. Eaton & N. Medlin .

Wilkes County: 12) NCSM 90232 — Stony Fork at CR 1167 bridge, Stony Fork Rd., N 36.1773 W 81.4654, 1 MI, 1 F, 1 M juv, 19 November 2020, M.A. Perkins, W . T. Russ & W.J. Russ; 13 ) NCSM 90233 — Stony Fork at SR 1167 bridge, Stony Fork Rd., approximately 50 m downstream of Stony Fork Falls, N 36.1695 W 81.4659, 1 MI, 2 F, 2 M juv, 19 November 2020, M.A. Perkins, W . T. Russ & W.J. Russ; 14 ) NCSM 90234 — Left Prong Stony Fork at SR 1155, Lee Mountain Rd., N 36.1504 W 81.4652, 2 MI, 19 November 2020, M.A. Perkins, W . T. Russ & W.J. Russ; 15 ) NCSM 90231 — Stony Fork at SR 1167, Stony Fork Rd., N 36.1561 W 81.4563, 1 M juv, 20 November 2020, M.A. Perkins & B.W. Williams .

Conservation status. Cambarus lapidosus is locally common but narrowly distributed in the headwaters of a single small watershed in western North Carolina, with an estimated current extent of approximately 85 km 2. The population size for C. lapidosus is currently unknown. While an assessment of threats to the stability of the species is incomplete at this time, habitat degradation and diminished water quality from agriculture and silviculture impact some areas of the watershed, and necessitate future monitoring. Because of these threats, coupled with the species’ narrow distribution, we suggest that the species be assigned the status of G1/S1 (Endangered) based on NatureServe criteria (NatureServe 2020;) and Endangered ( EN) based on International Union for the Conservation of Nature criteria ( IUCN 2001; B2 a,b i-iv).

Variation. Approximately 88% of the 26 individuals examined possess at least one subpalmar tubercle on the ventral palm of each chelae; 4% of individuals examined possess two subpalmar tubercles. Juveniles and sub-adults lack well-developed chelae making detection of subpalmar tubercles—a key character in identification of this species—difficult. As with other species in the genus Cambarus , C. lapidosus exhibits sexual dimorphism in reproductive structures. We have not observed any obvious spatial variation in this species.

Life history. Collections of C. lapidosus have been limited to the months of July, October, and November. First and second form males have been observed in October and November. Females in glare have been observed in November 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 are thought to occur with C. lapidosus including C. species C, and members of the Cambarus longulus Girard, 1852 and Cambarus bartonii (Fabricius, 1798) species complexes. Cambarus [aff.] dubius Faxon, 1884 , a primary burrower, was observed in burrows along stream banks.

Relationships and comparisons. Cambarus lapidosus is superficially similar to several described species and yet-diagnosed members of the genus Cambarus in Atlantic Slope and interior basin streams. Cambarus lapidosus was previously subsumed within C. species C, the dominant species complex occuring in Atlantic Slope drainages in the Mountain and Piedmont ecoregions of NC. Cambarus species C from the upper Yadkin and adjacent Catawba basins in NC represents at least one morphologically distinct species and can be differentiated from C. lapidosus by the absence of subpalmar tubercles on the palm of the chelae and the presence of conspicuous cervical spines. The lower reaches and small tributaries of the Stony Fork watershed are dominated by C. species C, from approximately downstream of Stony Fork Falls to near the confluence with the mainstem Yadkin River; however, the two taxa do co-occur in some reaches downstream, and in the proximity, of Stony Fork Falls, and in the lower Left Prong Stony Fork. Stony Fork Falls appears to be a barrier to upstream migration of C. species C, but not to downstream movement of C. lapidosus .

Despite its historic affiliation with C. species C, C. lapidosus is more morphologically and genetically similar to undiagnosed forms of C. aff. robustus occurring in interior basins of the NC mountain region. These yet undescribed forms—from the New and Watauga River basins—both possess a more widely-punctate areola (8–10 punctations) and sometimes lack the subpalmar tubercles on the palm of the chelae more often-exhibited by C. lapidosus . Futhermore, C. lapidosus is not known to occur in any interior basin streams, and is therefore geographically isolated from other taxa currently subsumed within the C. robustus complex.

Cambarus lapidosus is genetically most similar to C. burchfielae , described below, which occurs in the neighboring Lewis Fork drainage. These species are easily morphologically distinguished from each other despite their genetic and geographic affinities. Cambarus burchfielae typically lacks a double row of well-developed cristiform tubercles on the mesial margin of the chelae and tubercles on the dorsal surface of the dactyl are absent or greatly reduced, possesses a narrower and more-sparsely punctate areola (4–5 punctations), and typically lacks the rusty pigment patch on the dorsal surface of the carapace immediately anterior of the abdomen common to C. lapidosus , C. species C, and Cambarus johni Cooper, 2006 . 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 lapidosus is easily distinguished from other congeners in the upper Yadkin River basin. C. aff. bartonii is a small species characterized by a wide and truncate rostrum, single row of tubercles on the mesial margin of the chelae, and narrow sparsely punctate areola (3–4 punctations). 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; the species is not known to occur upstream of Stony Fork Falls. Cambarus johni lacks subpalmar tubercles on the chelae and 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; the species has not been found with C. lapidosus but may co-occur downstream of Stony Fork Falls.

Etymology. The species epithet “ lapidosus ” (Lat.) as an adjective in the nominative case means stony or rocky, which we use in reference to the Stony Fork, the small tributary of the Yadkin River in western North Carolina which harbors the entire known range of this species.

Common name. We propose Stony Fork Crayfish as the common name for this species in reference to its occurrence in the Stony Fork watershed.

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 4. Cambarus lapidosus, holotype (NCSM 90222) in life (photo credit: Michael A. Perkins, NCWRC).

FIGURE 5. Cambarus lapidosus, (left) second form male morphotype (NCSM 90224) in life, Stony Fork, Wilkes County, NC; (right) female allotype (NCSM 90223) in life, Orchard Creek, Watauga County, NC (note: regenerated left chela with single row of mesial tubercles); (photo credit: Michael A. Perkins, NCWRC).

FIGURE 6. Stony Fork, facing south near the type locality of Cambarus lapidosus, in Watauga County, NC—25 October 2019 (photo credit: Michael A. Perkins, NCWRC).

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.