This species is known from the eastern margins Sierra Madre Oriental of Hidalgo, Mexico, where it has been recorded from northern Puebla and Veracruz at 1,000-2,000m asl (though it mainly occurs at higher elevations within its range).
Habitat and Ecology
This is a terrestrial species that inhabits the pine-oak-cloud forest interface, and is able to live in somewhat disturbed habitats. It reproduces by direct development.
Formerly quite abundant, this species has become very hard to find in recent years. For example, a visit to the known locality of Cerro Loma Alta in 2003 yielded no records of this species (last found there in 1999). It also used to be common at La Joya, but was last recorded there in 1997.
Serious habitat destruction is taking place within its range as a result of logging, mining, agriculture, and human settlement. All areas surrounding La Joya have been highly disturbed as a result of extensive logging and mining, and the remaining available habitat at this locality was only about 15 ha in 2004. Another known locality, Cerro Loma Alta, which was visited in 2003, was found to have been virtually destroyed as a result of logging and invasive plants.
It is not known from any protected areas, making habitat protection for this species an urgent priority.
Red List Status
Critically Endangered (CR)
Listed as Critically Endangered because there have been continuing dramatic population declines, estimated to be more than 80% at known localities over the last three generations or ten years, in the extent and quality of its severely fragmented forest habitat.
This species was removed from the synonymy of Pseudoeurycea bellii by Parra-Olea, Papenfuss and Wake (2001).
Gabriela Parra-Olea, David Wake, Ted Papenfuss 2008. Isthmura gigantea. The IUCN Red List of Threatened Species 2008: e.T59380A89371649. http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T59380A11911830.en