Four-toed Salamander
Hemidactylium scutatum
Summary: Usually associated with forested fens or other seepage-fed wooded wetlands, this species is known from a handful of localities in Will, Porter, and LaPorte Counties. Historical records in northern Cook and southeastern Lake Counties, Illinois are old and apparently no longer exist.
Description: Although superficially similar to the redback salamander - with which it co-exists at the Indiana sites - upon close inspection, the four-toed salamander is actually quite distinct. It is a small salamander, 2.0 to 4.0 inches (5.1-10.2cm) total length. There are only four toes on each foot (most salamanders have five toes on the hind feet), and a constriction at the base of the tail. The most conspicuous character is the enamel white underside, speckled with small black dots. Above, it is coppery-brown or reddish-brown, with a weak herringbone pattern sometimes evident on the back.
Distribution and Status: Until a few years ago, the only place to find four-toed salamanders in the Chicago region was in a few parts of the Indiana dunes area. Historical records north of Chicago, in northeastern Cook and southeastern Lake Counties, all dated from before 1932. In 1995, Tom Anton found a four-toed salamander at a Will County site (Anton et al., 1998). Two additional specimens were located there in the same year. Then in 1999, while conducting wetland inventories in northern LaPorte County, I found an adult four-toed salamander there. Because this salamander tends to occupy geographically small portions of any site, and because it is easily overlooked, it is likely that a few more populations await discovery in the region.
The four-toed salamander is listed as state threatened in both Illinois and Indiana.
Habitat: The Will County site includes a seepage-fed pond in mesic woodland. This habitat type also occurs in the vicinity of the historic Lake County populations. The Porter and LaPorte County populations occupy forested fen. All regional populations to date are associated with neutral to calcareous seepage. Frequent literature references to the use of "bogs" (Petranka, 1998 and many others) are a classic example of herpetologists misunderstanding community classification. At least in the Chicago region, there is no documentation of the use of acidic habitats.
In the Missouri Ozarks, I have seen several individuals well away from water on hillsides and upper ravine slopes. Although always in wooded habitat, some of these locations were surprisingly dry. This implies that overland dispersal is not uncommon.
Phenology: Because of the limited number of local observations, little is known about behaviour. Courtship may occur fall or spring, and in southern Michigan egg deposition occurs in mid to late April (Blanchard, 1934). The first Will County specimen was found guarding a clutch of eggs on May 1 (Anton et al., 1998). The eggs are deposited within moss mats or under debris above or adjacent to water, with the aquatic larvae dropping or wriggling into the pond upon hatching, which occurs in late May (Blanchard, 1923; Bishop, 1941). In Michigan the larval period lasts about six weeks, with metamorphosis in early July (Blanchard, 1923).
Surface activity by adults is probably greatest in mild and moist spring and fall weather. However, I have seen specimens on hot August afternoons, and in snow flurries on November 1.
Literature Cited
Anton, T. A., D. Mauger, R. A. Brandon, S. R. Ballard, and D. M. Stillwaugh, Jr. 1998. Distribution, habitats, and status of four-toed salamanders in Illinois. Pp. 45-48 in: M. J. Lannoo (ed.), Status and Conservation of Midwestern Amphibians. University of Iowa Press.
Bishop, S. C. 1941. Salamanders of New York. New York State Museum Bulletin 324:1-365.
Blanchard, F. N. 1923. The life history of the four-toed salamander. American Midland Naturalist 57:262-268.
Blanchard, F. N. 1934. The date of egg-laying of the four-toed salamander, Hemidactylium scutatum (Schlegel) in southern Michigan. Papers of the Michigan Academy of Sciences, Arts, and Letters 19:571-575.
Petranka, J. W. 1998. Salamanders of the United States and Canada. Smithsonian Institution Press.
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| Updated: October 9, 2007
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