Desmognathus balsameus, Pyron & Beamer, 2022

Pyron, R. Alexander & Beamer, David A., 2022, Systematics of the Ocoee Salamander (Plethodontidae: Desmognathus ocoee), with description of two new species from the southern Blue Ridge Mountains, Zootaxa 5190 (2), pp. 207-240 : 225-226

Desmognathus balsameus sp. nov.

Holotype: AMNH A-193885 ( RAP0650 ; Fig. 16 ), collected 12 April 2019 by RAP from Bubbling Spring Branch near Mount Hardy Gap ( NC: Haywood; 35.308, -82.908, ~ 1530m ASL).

Paratypes: AMNH A-193884 & A-193886 ( RAP0649 & 0651), as from the type . MNHN 2021.0115 & BMNH 2021.7526 ( RAP0644–5 ), collected 12 April 2019 by RAP on Green Ridge ( NC: Haywood; 35.353, -82.917), ~ 1110m ASL . NCSM 108355 ( RAP0647 ), collected 12 April 2019 by RAP near Sunburst Falls ( NC: Haywood; 35.338, -82.904), ~ 1260m ASL .

Diagnosis: Several phenotypic characters exhibit varying combinations of states which are purported to be diagnostic and differentiate D. balsameus from related or similar taxa. This species is a small (~ 19–47mm SVL; n = 22), primarily terrestrial mountain dusky salamander with a tail shorter than the body (up to ~90% SVL) that is round in cross section along its length. It is differentiated from D. santeetlah by the lack of any keeling on the dorsal surface of the tail (vs. presence thereof), which is the only species in its range with which it is likely to be confused. Exhibits a wide range of color patterns, with most individuals possessing a partially or mostly complete dorsal stripe with wavy or undulating edges (vs. usually straight in D. adatsihi ), formed from the irregular invasion of melanophore patches between the remnants of paired larval spots, with a brownish, yellowish, or reddish coloration against a darker lateral ground color, and a general lack of any regular patterning along the mid-dorsal line ( Figs. 17–18 ). Ontogenetic darkening seems to be relatively more common and at smaller sizes than in related species, with individuals as small as ~ 33mm SVL exhibiting overall dark brown to blackish coloration obscuring the dorsal pattern ( Fig. 12b , 14b , 18b , 19a ).

Distribution: In the Great Balsam Mountains of western North Carolina at elevations above ~ 1000m ASL, primarily in Haywood, Jackson, and Transylvania Counties, but possibly extending into western Buncombe and Henderson Counties ( Fig. 4 ).

Etymology: From the Latin balsamum for “balm,” after the Fraser fir trees ( Abies fraseri ), known in the past as the “she-balsam” or “balsam fir” for which the Great Balsam Mountains are also named ( Fig. 19b ), though now treated as distinct from the Balsam fir A. balsameus . Name is a Latin singular adjective in the nominative case, masculine gender. We suggest the common name “Great Balsams” Mountain Dusky Salamander.

Notes: Comprises the ocoee B lineage defined by Kozak et al. (2005), Beamer & Lamb (2020), and Pyron et al. (2020, 2022c).

The fourth species in our taxonomy represents the resurrection of Desmognathus perlapsus Neill, 1950 for the ocoee C/D lineage, which shares hybrid non-lineal mitochondrial ancestry with the Balsam clade but is otherwise genealogically exclusive and topologically distinct from D. adatsihi and D. balsameus (see Pyron et al. 2022c). The primary expansion of this taxon concept here is the inclusion of populations previously referred to D. conanti from the Chattahoochee River drainage in the Piedmont of Georgia and Alabama, as reported by Beamer & Lamb (2020) and corroborated by Pyron et al. (2022c). The ocoee C lineage reported by Kozak et al. (2005) is a member of this species and exhibits reciprocal admixture with adjacent ocoee E and possibly ocoee F/G/H populations in the southern Nantahala Mountains ( Pyron et al. 2022c). The ocoee D lineage is otherwise genetically cohesive and comprises northern and southern phylogeographic sublineages with a broad hybrid zone across the Blue Ridge/ Piedmont transition. Correspondingly, we offer a re-description of:

Figures

FIGURE 4. Map of the five species considered by our taxonomy from genetically verified recent localities (RAP collection; Anderson & Tilley 2003; Beamer & Lamb 2020; Karlin & Guttman 1986; Kozak et al. 2005; Means et al. 2017; Pyron et al. 2022c; Tilley 2000; Tilley et al. 1978, 2008; Tilley & Mahoney 1996). We include apalachicolae A2 and ocoee E within our concept of D. ocoee, for which the nominotypical lineage is ocoee F/G/H. Note that some individuals from these populations are admixed between one or more species, and hybrid zones exist between phylogeographic lineages within D. ocoee and D. perlapsus, primarily at the geographic margins where each adjacent lineage contacts its neighbor. Type localities are indicated with triangles, the population of unknown affinity from Horse Cove (GA: Gilmer; Fig. 21) is indicated with a gray dot, and the potential Cohutta populations are indicated with a “?.”

FIGURE 12. Comparison of large, darkened adult males (based on elongated snouts and peramorphic jaw musculature) of Desmognathus adatsihi (a: RAP2816; Rough Ridge, NC: Haywood) and D. balsameus (b: RAP2827; Bear Pen Gap, NC: Jackson; Fig. 16a) in life, showing the similar overall melanic coloration taken on with age. Photos courtesy of M.A. Seldes (UGA).

FIGURE 14. Comparison of small adult Desmognathus adatsihi (a: not collected; Clingmans Dome, TN: Sevier/NC: Swain) and exceptionally large (54mm SVL) adult D. balsameus (b: RAP2831; Lost Knob, NC: Jackson) in life, showing the dramatic possible differences in body form and coloration. Photos courtesy of M.A. Seldes.

FIGURE 16. The holotype (AMNH A-193885/RAP0650) of Desmognathus balsameus from Bubbling Spring Branch (NC: Haywood), ~1530m ASL. This adult specimen (43mm SVL) has a relatively dull dorsal color-pattern partially obscured by ontogenetic darkening, common in this species. Photos by RAP.

FIGURE 17. Comparative specimens of Desmognathus balsameus in preservative in dorsal (a, c) and ventral (b, d) views, showing dorsal stripe with wavy or undulating edges (RAP0979; Black Balsam Knob, NC: Haywood; a, b), and the early ontogenetic stage of this pattern with more distinct paired spots (RAP0990; Burnette Cove Creek, NC: Haywood; c, d).

FIGURE 18. Photographs of a juvenile (a: RAP2824) and adult (b: RAP2825) Desmognathus balsameus from Bear Pen Gap (NC: Jackson) in life. Photos courtesy of M.A. Seldes.

FIGURE 19. Live photograph of two large adult male Desmognathus balsameus (RAP2826–7) in combat (a), found in situ under a log in the understory of a coniferous forest (b) near Bear Pen Gap (NC: Jackson; ~1670m ASL). No females were observed nearby, suggesting a possible territorial nature for the interaction. Both individuals show overall darkened adult coloration with few if any discernable color-pattern remnants.Adult Eurycea cf. wilderae and Plethodon metcalfi were found under similar logs, and D. wrighti is known from the site (Pyron et al. 2022c). The encounter occurred at ~1000h on 24 July 2022 and was found by M.A. Seldes. Photos by RAP.