Etymology

    Hemidactyium, the generic name, is an adjective meaning "with half-fused digits." It derives from the Greek hemi, "half," plus Greek dactylios , dactylium, a medical term for the fusion of digits ( dactylos , "finger"). The word is Latinized from the Greek. The salamander is so called because of the reduced number of digits on its hind legs. The specific name scutatum is the Latin adjective scutatum , "equipped with a shield" ( scutum , "shield"). The name is suggested by H. scutatum's costal grooves, which when viewed from above resemble overlapping plates.

Nomenclatural History

Both Tschudi's generic name Hemidactylium and Schlegel's specific name scutata have been widely accepted since their proposals. The generic name Desmodactylus, proposed by Dumeril, Bibron, & Dumeril, has rarely been used; nor has Gibbes's specific name melanosticta .

    Range

Southern Ontario and Maine westward to Wisconsin, south to Georgia and Alabama; also Arkansas, Missouri, and Illinois. All over Connecticut, in the following habitats:

    Habitat

Typical habitat.

Adults live in and around mossy logs and other damp nooks and crannies in swamps, quiet ponds, larch meadows, and especially sphagnum bogs. Adults are completely terrestrial.

    Size

The four-toed salamander is among the smallest of all salamanders. Males range from 2 to 3" (50-76 mm.) in length, with average 2 9/16". Females are slightly larger: 2 7/8-31/2 (62-89 mm.).

    Appearance

  Significant features:

"The body is nearly cylindrical, the trunk short, and provided with an impressed median line. The tail is broadly oval in section at the base, swollen at mid-length, and only slightly compressed distally. At the base of the tail there is a definite constriction marking the point of detachment in autonomy. The head is somewhat flattened, the snout bradly rounded in the female and squarely truncate in the male. There are 13-14 costal grooves and the gular fold is well formed. The legs are slender but relatively strong, toes 4-4, inner and outer rudimentary. Vomerine teeth in the male are in single backward-curving lines, usually separated from the parasphenoid patches. In the female the vomerine series may consist of 2 or more irregular rows. The tongue is small, narrow, and bluntly rounded behind and in front. The head and trunk above reddish brown, fading slightly on the upper sides and red patch. The venter is bluish-white, with small, irregular, inky-black flecks scattered over the surface. The mature males differ from the females in their smaller average size, more slender form, relatively longer tail, more squarely truncate snout, and the disposition of the vomerine teeth. The 3 or 4 teeth on the premaxillary of the male are enlarged and sometimes perforate the lip." (Sherman C. Bishop, Handbook of Salamanders, 1943. Comstock Publishing Co., Ithaca, New York. pp.306-309.)

    Breeding

Female with eggs.

The mating season of the four-toed salamander extends through late summer and fall. Fertilization is external: The male leaves his spermatophore - a packet of sperm - on a surface, and the female positions herself so that it enters her cloaca.
   "In early spring, the females leave their winter quarters and migrate to the breeding grounds. The eggs are deposited in close proximity to water and usually in little cavities in sphagnum moss or among the roots of grass, rarely in rotting wood. The approximately 30 eggs are deposited [individually] and are not aggregated by a common envelope, but cling to one another and to the nest materials by the adhesive outer envelope. When depositing her eggs the female turns upon her back. Usually the female remains with the eggs until they hatch, and often many females will deposit their eggs in such close proximity to one another that it is impossible to determine the limits of individual masses. Under these circumstances only a few females remain in attendance. The individual egg has a diameter of 2.5-3 mm. and is surrounded by two envelopes, in addition to the vitelline membrane, which give a total diameter of about 5.3 mm." (ibid.) The incubation period lasts anywhere between 38 and 60 days.

    Larvae

Like all other salamanders of the family Plethodontidae, four-toed salamanders emerge from the egg looking basically like miniature adults. However, they do go through a distinct larval phase before adulthood. Larvae have gills, and a keel running down the entire length of the back and tail. Color and proportion differ too: "Larvae at hatching average about 1/2" (12.4 mm.). The head is broad, the snout bluntly pointed. The trunk and tail are strongly compressed and wedge-shaped. The fore legs [sometimes] have 4 [distinct] toes, the hind legs short and directed backward. The gills are slender, tinged with orange at the base, and pigmented with black....The head of the larva is tinged with orange, green, and yellow, and marked with dark brown or black. On the side of the head, a short, wide, dark bar extends from the eye to the gills. Along the mid-line of the trunk there is a light band with irregular edges bordered each side by dark worm-like markings." (ibid.) The larvae remain aquatic for about 6 weeks before emerging onto land for good. The four-toed salamander reaches sexual maturity in about 2 1/2 years.

    Bishop, Sherman C. 1943. Handbook of salamanders: the salamanders of the United States, of Canada, and of Lower California. Comstock Publishng Co., Ithaca, New York.

    Blanchard, Frank N. 1923. The life history of the four-toed salamander. Amer. Nat., 57:262-268.

    Neill, Wilfred T. 1963 Hemidactylium scutatum. Cat. Amer. Amphib. Rept.: 2.1-2.2.

    Wood, John T. 1953 Observations on the complements of ova and nesting of the four-toed salamander in Viginia. Amer. Nat., 87:77-86.

    American Museum of Natural History, Department of Herpetology website: "Amphibian Species of the World." Accessed 4/23/00.

    Bishop, Sherman C. 1920. Notes on the habits and development of the four-toed salamander, Hemidactylium scutatum (Schlegel). Bull. New York State Mus., (219-220) :251-282.

    Blanchard, Frank N. 1933a. Spermatophores and the mating season of the salamander Hemidactylium scutatum (Schlegel). Copeia, 1933:40.

   --- 1934b. The spring migration of the four-toed salamander, Hemidactylium scutatum. Ibid., 1934:50.

   --- 1934c. The relation of the female four-toed salamander to her nest. Ibid., 1934:50.

   --- 1934d. The date of egg-laying of the female four-toed salamander, Hemidactylium scutatum(Schlegel), in Southern Michigan. Papers Michigan Acad. Sci. Arts and Letters, 19:571-138.

    Blanchard, Frank N., & Frieda C. Blanchard. 1931. Size groups and their characteristics in the salamander, Hemidactylium scutatum (Schlegel). Amer. Nat., 65:149-154.

    Branin, M. Lelyn. 1935. Courtship activities and extra-seasonal ovulation in the four-toed salamander, Hemidactylium scutatum(Schlegel). Copeia, 1935:172-175.

    Cochran, Doris M. 1961. Living Amphibians of the World. Doubleday & Co., Garden City, New York. 199 pp.

    Dieckmann, Johanna M. 1927. The cloaca and spermatheca of Hemidactylium scutatum. Biol. Bull., 53:281-285.

    Freytag, Gunther E. Urodeles and Caecilians. Grzimek's Animal Encyclopedia, Dr.Dr.h.c. Bernhard Grzimek, ed.-in-chief. p. 309.

    Gibbes, L. R. 1844. Description of a new species of salamander. Jour. Boston Soc. Nat. Hist., 5:89-90, plate 10.

    Grant, William C., Jr. 1955. Territorialism in two species of salamanders. Science, 121 (3135):137-138.

    Humphrey, R. R. Ovulation in the four-toed salamander, Hemidactylium scutatum, and the external features of cleavage and gastrulation. Biol. Bull., 54 (4):307-323, figs. 1-8. 1928.

    Wood, John T. The nesting of the four-toed salamander, Hemidactylium scutatum (Schlegel), in Virginia. Amer. Midland Nat., 53:381-389.