Montana Field Guide

Long-toed Salamander - Ambystoma macrodactylum

Adults are dark gray to black with an irregular (sometimes broken or rarely absent) green to yellow stripe down the middle of the back. The longest toe on the hind foot is longer than the sole; this species lacks a groove running vertically from the nostril to the mouth. Adult body length is 2 to 3.25 inches. Eggs and Larvae: Eggs are typically laid in ponds in small clusters of 5 to 100, but eggs may be laid singly. Larvae are usually brown, have three external gills, and are relatively small (less than 1.75-inch body) and slender.

Montana Range

Long-toed salamanders are found in a variety of habitats from sagebrush to alpine. They typically breed in ponds or lakes, usually those without fish present. Adults go to the breeding ponds immediately after snowmelt and in western Montana are usually the first amphibians to breed. Like all salamanders, they have internal fertilization. Following breeding, they move to adjacent uplands. Eggs hatch in 3 to 6 weeks and metamorphosis takes 2 to 14 months (FWP). Migration routes to breeding pools showed no preference to habitat, relative soil moisture or vegetation, although individuals tended to move through same habitat (Beneski et al. 1986).

Larv: ostracods/cyclops; also red water mites, insect egg masses, algae (Franz 1951). Adult: terres. arthropods (mostly formicid coleop, diptera) 74%; aq. insect larv. (mostly tri- chop) 37% (Farner 1947).

Paedogenesis is unknown in this species. Earliest amphibian to breed in Pacific NW (Nussbaum et al. 1983).

In ID: breed Feb-May <2100m; Jun-Jul >2100m. Clutch size = 167 low elev, 90 high elev. Metamorph.: <2100m, at SVL 35- 40mm, yr.1; >2100m, at SVL 47mm, yr.2-4 (Howard and Wallace 1985). Meta- morph.: Aug-Sep (Brunson and Demaree 1951, Franz 1971). Sex. mature @ SVL 50mm