Eurycea hillisi Wray, Means, and Steppan, 2017
Hillis's Dwarf Salamander
Federal Protection: No US federal protection
State Protection: No Georgia state protection
Global Rank: G3
State Rank: S3
Element Locations Tracked in Biotics: Yes
SWAP 2015 Species of Greatest Conservation Need (SGCN): Yes
SWAP 2025 Species of Greatest Conservation Need (SGCN): Yes
2025 SGCN Priority Tier: Moderate Conservation Concern
Element Occurrences (EOs) in Georgia: 53
Habitat Summary for element in Georgia: Seepage ravines/stream sides; bogs; sphagnum beds, marshes
This is a tiny, slender salamander reaching a maximum known total length of 7.2 cm (2.8 in). Individuals have a bronze or coppery-brown back and sides, separated by a chocolate brown stripe that runs from each nare, through each eye, and along each side of the back and to the tip of the tail. Gray or white flecking is present on the sides and on the head. A herringbone pattern may be evident on the back between the limbs, sometimes continuing onto the base of the tail. The belly, especially posteriorly, is bright yellow, as is the anterior underside of the tail. The tail is round in cross-section. Only four toes are found on each hind foot (the vast majority of native salamanders have five toes). During the breeding season, males have elongated cirri (fleshy downward-pointing projections on each side of the upper lip). Larvae are unknown at this time.
In Georgia, Hillis’s dwarf salamander is most likely to be confused with another member of its complex, the dwarf salamander (E. quadridigitata). The belly of dwarf salamanders is pearly gray, in stark contrast to the bright yellow belly of Hillis’s. Other species in the dwarf salamander complex have yellow bellies, but those are not known to occur in Georgia. The larger southern two-lined salamander (E. cirrigera) looks similar to members of the dwarf salamander complex and may occur in the same habitats, but members of this species have hind feet with five toes. Prior to formal recognition of Hillis’s dwarf salamander as a distinct species, Georgia populations of yellow-bellied dwarf salamanders were considered as Chamberlain’s dwarf salamander (E. chamberlaini), a species now thought to be restricted to the Carolinas.
Bay swamps, the periphery and upper end of beaver ponds, isolated wetlands, and lazy first-order streams and seepage ravines provide habitat for this species. Sphagnum moss (Sphagnum spp.) is commonly extensive in appropriate habitat and provides ideal shelter and moisture for the salamanders. Larvae are presumed to occur in flowing water within and near adult habitats.
Unknown, but presumably small terrestrial invertebrates for adults and tiny aquatic invertebrates for larvae.
Very little is known about this newly discovered species. Gravid females have been found in March, suggesting nesting likely takes place in March and April. Newly metamorphosed juvenile Hillis’s dwarf salamanders appear in June.
Hand-raking through mats of sphagnum moss and moist leaf litter and flipping cover objects (logs, rocks, etc.) in appropriate habitat is the most effective means for encountering Hillis’ dwarf salamanders. Coverboard arrays and drift-fence trapping may be effective. Salamanders may also be found crossing roads on rainy nights. Save for the colder winter months, individuals may be found most of the year. Because of the influx of new metamorphs joining habitat with adults in June, sheer numbers of individuals present make this an ideal time to focus survey efforts.
This species ranges from eastern Georgia, west through the southern half of Alabama, and into the central panhandle of Florida. Georgia populations form a relatively narrow band just above (Piedmont) and just below (Coastal Plain) the Fall Line in eastern and central Georgia, but extend southward, deeper into the coastal plain within the Chattahoochee River drainage.
Habitat loss and disturbance is likely the primary threat for this species, as it is for most of Georgia’s rare wildlife. However, the specific habitat types where this salamander is most often found are thankfully not among our most sensitive and imperiled. It is unknown at this time how sensitive Hillis’s dwarf salamander may be to some of the emerging infectious diseases that have impacted other amphibians.
| Threat 1 | Threat 2 | Threat 3 | |
|---|---|---|---|
| General Threat | Climate change & severe weather | Agriculture & aquaculture | Residential & commercial development |
| Specific Threat | None | None | None |
A 2016 survey for “Chamberlain’s” dwarf salamander documented forty-three new sites, bringing the total known sites in Georgia to nearly sixty. This survey revealed a relatively low average encounter rate for occupied sites (2.54 salamanders per person hour) suggesting that many populations are fairly small. Populations found in the western Fall Line Sandhills region had the highest encounter rates (up to 10.3 salamanders/person hour).
So little is known about this species that any research into its natural history will benefit conservation efforts. In the meantime, habitat disturbance, including impacts to water quality, at sites known to harbor this species should be avoided.
Graham, S. P., and J. B. Jensen. 2011. Eurycea chamberlaini habitat. Herpetological Review 42:580.
Graham, S. P., D. Walker, C. Kelehear, and S. Hermann. 2016. Conservation status of Chamberlain’s Dwarf Salamander Eurycea chamberlaini, and One-toed Amphiuma, Amphiuma pholeter in Georgia. Unpublished report to Georgia Department of Natural Resources. 40 p.
Lamb, T., and D. A. Beamer. 2012. Digits Lost or Gained? Evidence for Pedal Evolution in the Dwarf Salamander Complex (Eurycea, Plethodontidae). PLoS ONE 7, e37544.
Wray, K. P., D. B. Means, and S. J. Steppan. 2017. Revision of the Eurycea quadridigitata (Holbrook 1842) Complex of Dwarf Salamanders (Caudata: Plethodontidae: Hemidactyliinae) with a Description of Two New Species. Herpetological Monographs 31:18–46
John B. Jensen
4/12/18
