Desmognathus aureatus ( Martof, 1956 )

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 : 273-274

Desmognathus aureatus ( Martof, 1956)

Leurognathus marmorata aureata Martof, 1956

Leurognathus marmorata roborata Martof, 1956 , holotype UMMZ 111568 by original designation, collected 18 September 1954 by “the Bernard Martof family,” type locality “Reed Creek, along Burrell Ford Road, 0.5 of a mile from its junction with Glade School Road, about 3.5 miles northwest of Pine Mountain Community, Rabun County, Georgia; 2,350 feet elevation.” Paratypes UMMZ 111569 (lot of 26 specimens); same data. Informally synonymized with L. marmorata by Martof (1962) and resurrected by Dubois and Raffaëlli (2012) based on a suggestion by Jones et al. (2006). Here designated a junior subjective synonym of D. aureatus .

Holotype: UMMZ 111566 by original designation, collected 11 September 1954 by “ Stephen and Andrew Martof ,” type locality “ Jarrard’s Creek , 0.2 of a mile below its crossing of U.S. Route 19, about 9 air miles north-northeast of Dahlonega, Lumpkin County, Georgia; 1,550 feet elevation.”

Paratypes: UMMZ 111567 (lot of 20 specimens); “data as for the holotype.”

Description: After Martof (1956), adults of this species have no vomerine teeth (versus presence in Desmognathus intermedius and D. marmoratus [some females]); ventral color-pattern pale or mottled (versus dark or black in other Blue Ridge lineages); and dark brown to black background of dorsum with dorsal color-pattern consisting of paired, golden, marbled or lichenous blotches (albeit less distinct in northeastern populations previously assigned to L. m. roborata Martof, 1956). These characters should be re-evaluated for diagnostic consistency. In our sample, this is the smallest shovel-nosed species, with metamorphosed SVL = 34–73mm. Based on our size-corrected linear morphometric analyses, this species can be distinguished from D. intermedius by a shorter trunk (AG in original measurements = 17–40mm) and from D. marmoratus by a longer head (SG in original measurements = 8.1–17.1mm). From Martof (1962), females at sites in Georgia develop sexual maturity around 55–59mm SVL, typically laying 27– 54 eggs from May to July, with clutch size dependent on body size. Hatchlings are as small as 10–12mm SVL and metamorphose at 25–38mm (usually ~30) after 10–20 months, though up to three distinct size classes at some suggest possibly longer periods up to ~36 months. Larvae and adults are primarily insectivorous, likely preying opportunistically on available aquatic invertebrates ( Martof and Scott 1957). Adults in some Georgia populations are occasionally bright yellow, a characteristic that apparently shifts rapidly in frequency within populations over short timescales ( Martof and Walton 1965).

Range: The Blue Ridge Mountains of northeastern Georgia, northwestern South Carolina, and small portions of the nearby border regions of North Carolina, in headwater streams of the Chattahoochee, Chattooga, and Tallulah River drainages ( Fig. 1 ; Voss et al. 1995; Jones et al. 2006). Elevational range ~ 400–1100m.

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

Etymology: The specific epithet is a Latin singular adjective in the nominative case meaning “adorned with gold,” in reference to the dorsal coloration ( Fig. 7 ).

Standard English Names: For Desmognathus aureatus: Golden Shovel-nosed Salamander ( Conant 1958); for Leurognathus marmoratus roboratus Martof, 1956 : Husky Shovel-nosed Salamander ( Conant 1958). We suggest that “Southern” Shovel-nosed Salamander is more 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: Implicitly synonymized with Leurognathus marmoratus ( Moore, 1899) by Martof (1962). Indirectly suggested for resurrection by Jones et al. (2006), though this was essentially ignored. Later explicitly resurrected by Dubois and Raffaëlli (2012), though few subsequent authorities followed this arrangement. Part of the Nantahala clade ( Jones and Weisrock 2018; Pyron et al. 2020, 2022c) and the sister lineage of the Dwarf Black-bellied Salamander Desmognathus folkertsi Camp, Tilley, Austin, & Marshall, 2002 . The presence of the shovel-nosed phenotype in this lineage may have been transmitted to or from the Pisgah clade via an episode of ancient adaptive introgression (Pyron et al. 2020).

Within the Pisgah clade, Beamer and Lamb (2020) and Pyron et al. (2020, 2022c) sampled specimens from the type localities of Leurognathus marmorata intermedia Pope, 1928 and L. m. melania Martof, 1956, which were highly similar genetically and belonged to the marmoratus C lineage. Therefore, we conclude that marmoratus C should be referred to as Desmognathus intermedius ( Pope, 1928) , including D. melanius ( Martof 1956) in synonymy. Consequently, the species D. melanius recognized by Frost (2019) following Dubois and Raffaëlli (2012) and Raffaëlli (2013) is not valid but is instead preoccupied by:

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 7. An adult Desmognathus aureatus from Pruitt Creek (GA: Lumpkin), near the type locality. Note the brighter yellow or golden lichenous dorsal blotches. Photo courtesy of MAS.