Hemidactylium scutatum (Temminck and Schlegel, 1838)
Click to enlarge
Batrachoseps scutatus, Salamandra scutata
Basis for Listing
Four-toed salamanders are widely distributed across forested regions of the eastern United States, with many disjunct and isolated populations throughout. This species was first discovered in Minnesota in Itasca County in 1994 (Dorff 1995). Since that time, it has been documented in five additional counties in east-central Minnesota. The four-toed salamander was listed as a species of special concern in 1996 due to its tendency to occur in small isolated colonies and its vulnerability to habitat destruction.
Four-toed salamanders have 4 toes on each of their front and hind feet. Other terrestrial salamanders in Minnesota have 5 toes on their back feet. This species averages 5-10 cm (2-4 in.) in total length (Petranka 1998). Its base color is red-brown with dark flecks on its sides. The belly of adults is white with black markings. Unlike other species of salamanders in Minnesota, the tail of the four-toed salamander may become detached from its body near a constriction at the base of the tail.
Throughout their range, four-toed salamanders live in mature upland deciduous or mixed deciduous-coniferous forests interspersed with sphagnum seepages, vernal ponds, or other fish-free habitats that serve as nesting sites (Pfingsten and Downs 1989; Petranka 1998). Mature closed-canopy forests provide favorable conditions including a shaded moist forest floor with organic soils and woody debris. Mature forests also encourage the growth of moss around pond margins (Petranka 1998). Upland forests provide cover, foraging sites, and overwintering habitat for juveniles and adults. Egg deposition and larval development occur in wetland habitats devoid of fish, often with a sphagnum component. In Minnesota, four-toed salamanders occur most frequently in mature forests of glacial moraine landscapes where such isolated wetlands are abundant.
Biology / Life History
Courtship and mating of four-toed salamanders occur in upland forest habitat in autumn (Petranka 1998). During courtship, males and females engage in a tail-straddle walk prior to the deposition of spermatophores by the males (Petranka 1998).
Conservation / Management
Throughout their range, four-toed salamanders are typically found in small, isolated colonies that are vulnerable to catastrophic events or drastic habitat alterations. The unique breeding habitat requirements (moss hummocks adjacent to both open water and mature forest habitat), and the limited dispersal capabilities of this species put its isolated populations at great risk. In Minnesota, the greatest threat to four-toed salamanders is loss and degradation of upland forest habitat and wetlands that are utilized as nesting sites. Where this species is known to occur, forest management and recreation activities should be designed to reduce impacts to four-toed salamanders and their habitats.
Conservation Efforts in Minnesota
More information on the distribution, abundance, movement, and ecology of this species in Minnesota is needed. The four-toed salamander is designated as a Regional Forester Sensitive Species in the Chippewa National Forest and surveys are to be conducted in proposed management activity sites that contain appropriate habitat. Within the DNR, the Minnesota Biological Survey conducts surveys for four-toed salamanders in counties with suitable habitat. These efforts have resulted in five additional county records between 1994 and 2008.
Dorff, C. J. 1995. Geographic distribution. Hemidactylium scutatum (Four-toed Salamander). Herpetological Review 26(3):150.
Hall, C., and B. Carlson. 2004. Forest management guidelines for the protection of Four-toed and Spotted Salamander populations. Minnesota Department of Natural Resources. Unpaged.
Harding, J. H. 1997. Amphibians and reptiles of the Great Lakes Region. The University of Michigan Press, Ann Arbor, Michigan. xvi + 378 pp.
Petranka, J. W. 1998. Salamanders of the United States and Canada. Smithsonian Institution Press, Washington D. C. 587 pp.
Pfingsten, R. A., and F. L. Downs, editors. 1989. Salamanders of Ohio. Ohio Biological Survey Bulletin 7(2):xx + 315 pp. + 29 plates.