Biology ETDs

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Plethodon neomexicanus, the Jemez Mountains Salamander, is endemic to the Jemez Mountains where it is restricted to talus slopes that are forested and shaded and that have suitable conditions of moisture and temperature. During the summer of 1966 four new localities were found, yielding information on the combination of factors which favor the presence of this salamander. Its habitat is at elevations of 7900-9200 ft within the upper montane forest of the Rocky Mountains. In the Jemez Mountains this forest exists at these elevations only on shaded north-facing slopes or in deep, shaded canyons. The presence of volcanic talus provides crevices for easy vertical movement or salamanders in response to fluctuating conditions. Salamanders were always found close to or within such an area, indicating a dependence on it. Plethodon neomexicanus is active at the surface when the temperature of the substratum is between 10.5 and 13.0 C and the surface litter is completely soaked. These conditions usually occur as a result of the first soaking rain of late spring and cease in September. At other times salamanders retreat beneath the surface and are not observed. Under favorable conditions, P. neomexicanus was observed to be active on the surface at night, probably foraging for food or seeking a mate. Neither activity was observed during this study due to the retreat of these salamanders on being exposed to light. The food identified from the stomachs of salamanders showed a variety of invertebrates, including small snails, beetle larvae, fungus gnats, and an abundance of ants. Intestinal nematodes, apparently nonpathogenic, were found in the course or this study. By statistical analysis it was determined that female salamanders are usually larger than males. Clutch size was estimated from mature follicles; but information on the nesting site, courtship, time of egg laying, and time of hatching was not obtained. Data on habitat, activity, and reproduction indicate a similarity of P. neomexicanus to the eastern small plethodons, supporting the hypothesis of Blair that P. neomexicanus is a relict species which became isolated from the eastern members of the genus as a result of the retreat of the Arcto-Tertiary forest.

Project Sponsors

I wish to express appreciation to Dr. William G. Degenhardt for his helpful suggestions and cirticism given throughout this study. I also wish to thank Dr. Loren D. Potter and Dr. Clifford S. Crawford for their advice, James L. Christiansen for help given on the reproductive aspects of this investigation, and Dr. C. Clayton Hoff for his identification of parasites and editorial assistance. I am also indebted to the U.S. Forest Service and to James P. Dunigan, President, Baca Land and Cattle Corporation, for permission to conduct this study on areas under their control. Special thanks are given to the American Museum of Natural History which provided assistance for this study through the Theodore Roosevelt Memorial Fund.



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Degree Name


Level of Degree


Department Name

UNM Biology Department

First Committee Member (Chair)

William George Degenhardt

Second Committee Member

Clifford Smeed Crawford

Third Committee Member

Loren David Potter

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