Plethodon pauleyi, Felix & Wooten & Pierson & Camp, 2019

Felix, Zachary I., Wooten, Jessica A., Pierson, Todd W. & Camp, Carlos D., 2019, Re-evaluation of the Wehrle’s salamander (Plethodon wehrlei Fowler and Dunn) species group (Caudata: Plethodontidae) using genomic data, with the description of a new species, Zootaxa 4609 (3), pp. 429-448 : 440-443

Plethodon pauleyi sp. nov.

Suggested English name: yellow-spotted woodland salamander

Figs. 6 & 7

Plethodon wehrlei (part), Cupp & Towles 1983, Redmond & Jones 1985, Waldron et al. 2001, Highton et al. 2012, Kuchta et al. 2018

Holotype. Museum of Zoology at Berkeley ( MVZ 291261) (field number: WV28 ) a female from Pipestem State Park , rock outcrops just uphill and along River Trail near Mercer / Summers County line, West Virginia, United States of America, 37.53573°N, - 81.01665°W (data = WGS84 ), 548 m asl, 8 May 2011, coll. Z. Felix.

Allotype. MVZ 291260 (field number: WV27 ) a male collected at same time and place as holotype.

Paratypes. (4) MVZ 291259, 291262 – 291264 (field numbers WV26, WV29–31) all with same collecting data as holotype.

Diagnosis. Our molecular data and those presented in earlier publications (e.g. Kuchta et al. 2018) place P. pauleyi within the genus Plethodon and more specifically within the P. wehrlei species group. Generally, this new species shares the morphology typical of woodland salamanders of the genus Plethodon and exhibits the expanded webbing between the toes found in other members of the P. wehrlei group. Plethodon pauleyi also shares the whitish irregular mottling that is found along the margin of the lateral and ventral sides of other members of the species group.

The most obvious feature that distinguishes P. pauleyi from P. wehrlei , P. punctatus , P. dixi , and P. jacksoni is the presence of two rows of yellow, dorsal spots. These loosely paired spots begin at or posterior to the insertion of the forelimbs and run down the dorsum to just posterior to the insertion of the hind limbs. These spots normally number between 6 and 12 on a side. Neither P. dixi nor P. punctatus normally have dorsal spots, and spots on P. wehrlei and P. jacksoni are reddish in color, never yellow. The spots are fainter in older individuals. Plethodon pauleyi is also distinguishable from other members of the species group by its ventral coloration. This new species has a grayish, translucent venter with lightly pigmented mottling whereas P. wehrlei and P. punctatus both have darkly pigmented venters with little mottling and a noticeably lighter gular region. Compared to the relatively dark, almost salt-and-pepper mottling on the venter of both P. dixi and P. jacksoni , the mottling on the venter of P. pauleyi is more lightly pigmented. Additionally, P. pauleyi can be diagnosed by having only two costal grooves between the adpressed limbs as opposed to three or four in P. wehrlei , P. jacksoni , and P. dixi ( Fowler & Dunn 1917; Pope & Fowler 1949; Newman 1954), and 2 or 3 in P. punctatus (ZIF unpublished data).

Holotype description (Fig. 6A) A mature female with yolked eggs (approximately 3.4 mm in diameter) and SVL of 52.4 mm. Post-preservation measurements were as follows (all measurements in mm; see Table 2 for description of measurements): AXW 5.2; PELW 4.9; HDL 11.2; HDHJM 4.1; HDHJA 3.4; HDWJM 6.7; HDWJA 7.8; IOW 2.6; OW 2.8; INW 2.3; OND 2.0; TWB 3.7; TW5CF 3.0; THB 3.0; TH5F 3.1; TOE1-4A 0.4, 1.4, 1.7, 1.1; TOE1-5P 0.5, 1.3, 2.1, 1.9, 0.9; FLL 11.2; HLL 15.3; FWA 3.7; FWP 5.2. There were seventeen costal grooves with two costal grooves between the adpressed limbs. In life, the dorsum was black to plumbeous and marked by two rows of conspicuous yellow, round, irregularly edged spots, each approximately 1–2 mm in diameter. There were eight spots on the left side and six on the right. Tiny white flecks were scattered across the head and neck between the forelimbs and along the dorsal surfaces of the brachia. These were most abundant on and above the eyes as well as directly above the insertion of the limbs. The sides of the face and trunk were gray and marked with irregularly edged, white mottling distributed from the lips, down each side at the margin of the lateral and ventral sides, to the insertion of the hind limbs. The venter between limbs and extending onto the tail was salt-and-pepper gray and

Allotype description (Fig. 6B, C) Mature male measuring 63.0 mm SVL with conspicuous mental gland (2.8 mm diameter). Post-preservation measurements were as follows (all measurements in mm): AXW 6.3; PELW 6.1; HDL 13.8; HDHJM 4.5; HDHJA 3.8; HDWJM 7.8; HDWJA 9.0; IOW 2.5; OW 3.3; INW 2.7; OND 2.5; TWB 4.5; TW5CF 4.0; THB 3.6; TH5F 3.3; TOE1-4A 0.4, 1.7, 2.0, 1.3; TOE1-5P 0.8, 1.7, 2.3, 2.5, 1.6; FLL 14.3; HLL 16.2; FWA 4.0; FWP 7.0. Costal grooves were 16. Two costal grooves between the adpressed limbs. In life, the dorsal surface was grayish brown. The paired, yellowish spots, seven on the right and seven on the left, were fragmented and faint. No other spotting was apparent on the dorsum. The lower sides of the face and body were gray with very few, widely scattered, small, white mottles. The venter was translucent with faint, fine mottling throughout.

Paratype variation ( Fig. 7 ). Additional paratypes ranged in SVL from 24.1–63.0 mm. Measurements for other morphological features are given in Table 3 . Each specimen possessed 16 costal grooves. Each individual also had two costal grooves between the adpressed limbs. All specimens had two rows of yellow spots in life that ranged in number from 6–10 on the right and 7–10 on the left side. In only one case were the number of spots on both sides equal. Spot intensity varied from bright yellow in small specimens to faint and fragmented in the largest, presumably oldest, animals. Additional size-related differences were that smaller specimens showed more numerous and intense small, white flecks on the dorsum (concentrated on the head and anterior portion of their trunk) as well as more intense white mottling on the margin of the lateral and ventral sides including on the throat. The background color of the dorsal trunk and limbs also seemed to lighten from a very dark gray or black in young individuals to dark, brownish gray with purplish-brown limbs in larger individuals. One mature male (63.52 mm SVL) had an obvious mental gland with a diameter of 2.4 mm.

Habitat and ecology. This species appears to be a rock-outcrop specialist and is found on shale or sandstone outcrops and rock faces that are relatively common on the Cumberland Plateau, especially along the plateau’s escarpment. While salamanders have been observed at the base of outcrops on leaf litter or rocks, they are most often found climbing on rocks after dark or sheltering in crevices during the day. Specimens have been collected in pitfall traps in West Virginia and Kentucky ( Waldron et al. 2001; J. MacGregor, pers. comm. to ZIF), indicating that individuals venture into surrounding woodlands to some degree. In such habitats, P. pauleyi is commonly found sympatrically with the green salamander ( Aneides aeneus Cope and Packard ), long-tailed salamander ( Eurycea longicauda Green ), and cave salamander ( Eurycea lucifuga Rafinesque ).

Distribution. Plethodon pauleyi is known from only 12 sites in Tennessee, Kentucky, and West Virginia, all within the Central Appalachian ecoregion ( US EPA 2006) south of the New River. The southernmost populations are mainly associated with Pine Mountain on the eastern edge of the Cumberland or Allegheny Plateau, also called the Allegheny Front. The northern populations are found in the more heavily dissected portion of the Plateau, especially in the New and Bluestone River gorges. It is likely that populations occur in the intervening areas and that the species will eventually be discovered in Virginia.

Etymology. The specific epithet honors Dr. Thomas K. Pauley, mentor of two authors (ZIF, JAW), Professor Emeritus from Marshall University, and protector of salamanders. Dr. Pauley studied P. wehrlei for his PhD dissertation and this new form in the Bluestone River gorge in West Virginia while a faculty member at Marshall.

Remarks. This form was originally discovered in the Cumberland Plateau of Kentucky and West Virginia ( Cupp & Towles 1983). Although it was clearly distinct phenotypically (and possibly ecologically), it was considered a variant of P. wehrlei because of its morphological similarity to that species and has since been treated as such (e.g. Petranka 1998; Highton et al. 2012; Kuchta et al. 2018). It is genetically unique. We recovered the well-supported monophyly of all samples of P. pauleyi —from West Virginia, Kentucky, and Tennessee—in our phylogenomic analysis. We found no evidence of introgression between this form and the other species and putative species within the P. wehrlei group, a result that is meaningful given the close proximity of West Virginia populations to populations of P. wehrlei . Similarly, Kuchta et al. (2018) provided evidence of genetic divergence between this species and P. wehrlei populations as close as ~ 9 km across the New River. Even with our limited sample of specimens, it is apparent that this species matures at a smaller size than P. wehrlei . The holotype contained yolked eggs at 52.4 mm SVL. In a sample of>1,000 P. wehrlei from New York, Pennsylvania, and West Virginia the smallest female with yolked eggs was 60 mm SVL ( Hall and Stafford 1972). Likewise, our type series included a male of 51.5 mm SVL that showed white vas deferens and testes with some pigmentation, indicating that it was approaching maturity. In P. wehrlei , the corresponding size of maturity for males is> 56 mm ( Hall & Stafford 1972). Because this form is genetically, morphologically, and ecologically distinct and thus clearly represents an independently evolving lineage, it meets the criteria of species under the General Lineage Species Concept ( de Queiroz 1998, 2005).

Figures

FIGURE 7. Type series of Plethodon pauleyi sp. nov. after preservation in 70% ethanol. From picture left to right are the holotype (MVZ 291261), allotype (MVZ 291260), and 4 paratypes (MVZ 291259, 291262, 291263, & 291264, respectively). Photographs shown at same scale and white scale bar is 10 mm. All photographs by Keith Ray.