CRCritically Endangered

Grand Minute Salamander

Thorius grandis

Stable

Overview

Thorius grandis, commonly known as the grand minute salamander, is a species of salamander in the family Plethodontidae. It is endemic to Mexico where it is found in west-central Sierra Madre del Sur in Guerrero. Its natural habitats are pine-fir and pine-oak-fir forests; it tolerates some habitat modification. It usually occurs under logs or the bark of fallen rotting logs. It is threatened by habitat loss caused by logging and expanding agriculture.

Thorius grandis faces severe population decline due to extensive deforestation and agricultural conversion throughout its limited montane cloud forest range in Mexico. The species' extremely restricted distribution makes it particularly vulnerable to habitat fragmentation, while climate change threatens to shift the cool, humid conditions essential for this moisture-dependent salamander. Chytrid fungal disease, which has devastated amphibian populations across Mesoamerica, poses an additional existential threat to remaining populations.
Threat summary

Habitat

Thorius grandis inhabits montane cloud forests at elevations between 2,000-3,000 meters in the Sierra Madre Oriental of Mexico. These salamanders require the cool, consistently humid microhabitats found under logs, rocks, and leaf litter in pristine cloud forest environments.

Forest· major

Conservation measures underway

Resource & habitat protectionSpecies recovery

Other threatened species in PLETHODONTIDAE

Honduran Lowland Worm Salamander

Oedipina quadra

Declining

Kings River Slender Salamander

Batrachoseps regius

Unknown

Conant's Mushroomtongue Salamander

Bolitoglossa conanti

Declining

Pygmy Web-footed Salamander

Bolitoglossa pygmaea

Stable

Threatened in Mexico

Frequently asked questions

Why is Grand Minute Salamander classified as Critically Endangered?

Grand Minute Salamander is classified as Critically Endangered — facing an extremely high risk of extinction in the wild — because population sizes are very small, declining sharply, or restricted to a tiny range. Thorius grandis faces severe population decline due to extensive deforestation and agricultural conversion throughout its limited montane cloud forest range in Mexico. The species' extremely restricted distribution makes it particularly vulnerable to habitat fragmentation, while climate change threatens to shift the cool, humid conditions essential for this moisture-dependent salamander. Chytrid fungal disease, which has devastated amphibian populations across Mesoamerica, poses an additional existential threat to remaining populations.

Where does Grand Minute Salamander live?

Grand Minute Salamander occurs in Mexico. Country-level distribution data is sourced from the IUCN Red List and cross-referenced with GBIF occurrences.

What are the main threats to Grand Minute Salamander?

The main threats to Grand Minute Salamander are 2.1, 5.1, 5.1.1, and 5.3. The full IUCN-classified threat record for this species is detailed on the species page.

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