Pseudoeurycea tenchalli is a microendemic terrestrial salamander restricted to the Sierra Madre del Sur in western Guerrero, Mexico. Classified as Critically Endangered (CR) by the IUCN, its primary threat is habitat loss, as the pine-oak forests it inhabits are among the most imperiled ecosystems globally. Additionally, knowledge about this species remains limited to the information provided in its original description (Adler, 1996). This research project will thus constitute the first formal study of Pseudoeurycea tenchalli. It aims to gather demographic, ecological, and physiological data, as well as to characterize the habitat utilized by this species. These data will be essential to assess the species' susceptibility from an integrative perspective, with the aim of implementing more effective in situ conservation measures. The specific objectives are: 1. To estimate the density and age and sex structure of the study population 2. To determine the thermal physiological parameters both in the field and in the laboratory 3. To evaluate the water loss rates 4. To characterize the temperature and humidity conditions present in the microhabitats used by P. tenchalli, as well as the vegetation cover and habitat use preferences 5. To evaluate the degree of vulnerability to habitat degradation and the effects of climate change 6. To develop environmental education activities in the community of Carrizal de Bravo and surrounding areas to inform about the effects of habitat disturbance on flora and fauna, and to carry out monitoring with local guides to locate other populations of P. tenchalli 7. To implement conservation measures by integrating the information obtained to ensure the conservation of P. tenchalli.