Desmognathus intermedius ( Pope, 1928 )

Pyron, R. Alexander & Beamer, David A., 2023, A systematic revision of the Shovel-nosed Salamander (Plethodontidae: Desmognathus marmoratus), with re-description of the related D. aureatus and D. intermedius, Zootaxa 5270 (2), pp. 262-280 : 274-276

Desmognathus intermedius ( Pope, 1928)

Leurognathus marmorata intermedia Pope, 1928

Leurognathus marmorata melania Martof, 1956 type specimen UMMZ 111564 by original designation, collected 4 Sepember 1954 by “the Bernard Martof family,” type locality “Otter Creek, tributary of the Nantahala River, 0.5 of a mile west of Tellico Gap, Macon County, North Carolina; 3,600 feet elevation.” Paratypes UMMZ 111565 (20 specimens); same data. Informally synonymized with L. marmoratus by Martof (1962) and resurrected by Dubois and Raffaëlli (2012) and Raffaëlli (2013) as D. “melianus” in error, though few subsequent workers followed this recommendation. Designated a junior subjective synonym of D. intermedius by Raffaëlli (2022).

Holotype: AMNH 25557 (a male) by original designation, collected 17 July 1927 by C.H. Pope, type locality “ Davis Gap, Waynesville , North Carolina ” and emended by Bishop (1943) to “ Davis Farm , about 2 miles east and a little north of Waynesville , (Haywood County) on Highway No. 276.”

Paratypes: AMNH 25544–25556 & 25558–25580 from the original type collection are listed as paratypes in the AMNH catalogue, but not explicitly designated as such by Pope (1928).

Description: Among shovel-nosed salamanders, Desmognathus intermedius can be diagnosed from D. aureatus by the presence of vomerine teeth in adults of both sexes, and from D. marmoratus by a more scattered and indistinct dorsal pattern in adults (after Pope 1928; Pope and Hairston 1947; Fig. 8 , 9 ). These characters should be re-evaluated for diagnostic consistency. Ironically given the original intent of the name “ intermedius ,” this is by far the largest shovel-nosed species in our sample with metamorphosed SVL = 28–85mm. Based on our size-corrected linear morphometric analyses, this species can be distinguished from both D. aureatus and D. marmoratus by a longer trunk (AG in original measurements = 14–45mm) and from D. marmoratus by a longer head (SG in original measurements = 6.5–20.0mm). After Martof (1962) and Bruce (1985), larvae are generally 15–35mm SVL, with a 3-year period until metamorphosis and oviposition and transformation both occurring in summer.

Range: In the Blue Ridge Mountains of western North Carolina and eastern Tennessee, confirmed in the Tennessee drainages of the Lower Little Tennessee, Upper Little Tennessee, Tuckasegee, Lower French Broad, Pigeon, and Upper French Broad Rivers ( Fig. 1 ). Curiously rare in or absent from the upper reaches of the Little Tennessee and Tuckasegee Rivers ( Martof 1962, 1963). An isolated population is known from the Black Mountains east of the French Broad River in the Upper French Broad drainage (O’Connell et al., unpubl. data). Elevational range ~ 300–1500m.

Habitat: As with all Shovel-nosed Salamanders, occurs almost exclusively in the rocky riffle zones of fast-flowing, high-gradient mountain streams.

Etymology: The specific epithet is a Latin singular adjective in the nominative case meaning “intermediate,” apparently referring to the species’ supposedly smaller size compared to D. marmoratus as known to Pope (1928) based on relatively few specimens.

Standard English Names: For Leurognathus marmorata intermedia : Pope’s Salamander ( Bishop 1943), Southern Shovel-nosed Salamander ( Schmidt 1953); for Leurognathus m. melanius: Black Shovel-nosed Salamander ( Conant 1958), Otter Creek Dusky Salamander ( Fouquette and Dubois 2014). We suggest that “Western” Shovel-nosed Salamander is most appropriate.

Conservation: This species is apparently widespread and abundant at numerous historical and recent sites across its range, a significant proportion of which is protected by state, federal, and private entities. Consequently, we suggest that it be considered “LC—Least Concern” based on available data ( Maes et al. 2015).

Notes: This lineage was previously recognized as a distinct species Leurognathus intermedia by Pope and Hairston (1947) before being demoted to a subspecies L. m. intermedia by Schmidt (1953) and informally synonymized with L. marmoratus by Martof (1962).

Figures

FIGURE 1. Map of genetic, specimen-vouchered, and literature localities for the three species of Shovel-nosed Salamanders, from our collections (RAP and DAB) and Martof (1956), Jackson (2005), Kozak et al. (2005), Wooten and Rissler (2011), Beamer and Lamb (2020), and Pyron et al. (2022c). Type localities are indicated with inverted triangles, and the site indicated in grey is a dubious locality reported by Wooten and Rissler (2011). Our extensive fieldwork at this and numerous other sites in the headwaters of the New (Kanawha) River yielded no specimens. State abbreviations are GA—Georgia, SC—South Carolina, NC—North Carolina, TN—Tennessee, VA—Virginia, and WV—West Virginia.

FIGURE 8. A large (75mm SVL) adult Desmognathus intermedius (RAP2814) from Wycle Fork (NC: Haywood) in life. Note the faded lichenous dorsal patches muddled into more indistinct blotches. Photo courtesy of MAS.

FIGURE 9. An adult Desmognathus intermedius from Little Santeetlah Creek (NC: Graham). Note the uniformly muddled dorsal blotches forming an indistinct pattern. Photo courtesy of MAS.