Rocky Mountain Tailed Frog, Inland Tailed Frog, Eastern Tailed Frog
© 2000 Brad Moon (1 of 5)
Can you confirm these amateur observations of Ascaphus montanus?
Ascaphus montanus Nielson, Lohman and Sullivan, 2001
Michael J. Adams1
Nielson et al. (2001) recommended that the genus Ascaphus be split into two species: tailed frogs (A. truei) and Montana tailed frogs (A. montanus). Their analysis was based on divergence of mitochondrial DNA and was consistent with previous allozyme work (Daugherty, 1979). The following account highlights references that are specific to the new species. Refer to the Ascaphus truei account for a complete review of the genus Ascaphus.
Montana tailed frogs occur in the Blue Mountains of southeast Washington (Metter, 1964a), central Idaho and the panhandle (Linsdale, 1933a; Corbit, 1960; Maughan et al., 1980), and western Montana (Smith, 1932; Franz and Lee, 1970) including at least one population on the eastern slope of the Rocky Mountains (Donaldson, 1934). Populations in the Wallowa Mountains of northeastern Oregon and the Seven Devils Mountains of western Idaho were not examined by Nielson et al. (2001) but were most similar to the Montana populations in Daugherty’s (1979) allozyme analysis. Ritland et al. (2000) found that interior British Columbia populations of Ascaphus were genetically distinct from coastal populations suggesting that the interior populations in Canada may also be Montana tailed frogs.
Mittleman and Myers (1949) reported that Montana tailed frogs have larger eyes and greater head width relative to body size than tailed frogs. However, Metter’s (1967) rangewide analysis failed to find geographic patterns in morphology for Ascaphus.The life history of Montana tailed frogs appears similar to tailed frogs although few comparisons have been made. Montana tailed frogs have a 3-yr larval period (Metter, 1967; Daugherty and Sheldon, 1982a) and appear highly philopatric (Daugherty and Sheldon, 1982b). Clutch sizes reported from natural nests (n = 2 nests; Franz, 1970) and from dissected females (Metter, 1964a, 1967) range from 33–97, which appears somewhat higher than tailed frog clutches from the Cascade Mountains and Coastal Ranges (reviewed by Bury et al., 2001). Montana tailed frogs may only oviposit every other year (Metter, 1964a). Adams and Frissell (2001) reported seasonal movements of adults consistent with an avoidance of warm water temperatures.
1Michael J. Adams
Literature references for Amphibian Declines: The Conservation Status of United States Species, edited by Michael Lannoo, are here.
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