CR

Oaxacan Pigmy Salamander

Thorius minutissimus

Declining

Overview

Thorius minutissimus is a species of salamander in the family Plethodontidae. It is endemic to Mexico. It is known only from one site near Santo Tomás Teipan in the Sierra Madre del Sur of Oaxaca, in pine–oak forest at 2,458 meters elevation. Its extent of occurrence (EOO) is 10 km2, which represents the single location.

Thorius minutissimus faces severe threats from habitat destruction due to agricultural expansion and logging activities in its restricted montane forest range. The species' extremely limited distribution makes it particularly vulnerable to localized environmental changes, with deforestation for coffee cultivation and cattle ranching fragmenting its cloud forest habitat. Climate change poses an additional threat by altering the moisture regimes essential for this moisture-dependent salamander's survival.

Threat summary

Habitat

This minute salamander inhabits cloud forests and pine-oak forests at elevations between 2,400-3,100 meters in the mountains of Oaxaca, Mexico. It requires moist microhabitats with abundant leaf litter and moss cover, typically found in undisturbed montane forest environments.

Forest· majorForest - Temperate· major

Conservation measures underway

Site/area protectionResource & habitat protectionSpecies recovery

Other threatened species in PLETHODONTIDAE

Honduran Lowland Worm SalamanderVU

Honduran Lowland Worm Salamander

Oedipina quadra

Declining
Kings River Slender SalamanderEN

Kings River Slender Salamander

Batrachoseps regius

Unknown
Conant's Mushroomtongue SalamanderVU

Conant's Mushroomtongue Salamander

Bolitoglossa conanti

Declining
VU

Pygmy Web-footed Salamander

Bolitoglossa pygmaea

Stable

Threatened in Mexico

EN

Turbinicarpus horripilus

Declining
CR

Turbinicarpus mandragora

Declining
EN

Opuntia pachyrrhiza

Declining
EN

Arachnothryx tacanensis

Declining

Frequently asked questions

Why is Oaxacan Pigmy Salamander classified as Critically Endangered?
Oaxacan Pigmy 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 minutissimus faces severe threats from habitat destruction due to agricultural expansion and logging activities in its restricted montane forest range. The species' extremely limited distribution makes it particularly vulnerable to localized environmental changes, with deforestation for coffee cultivation and cattle ranching fragmenting its cloud forest habitat. Climate change poses an additional threat by altering the moisture regimes essential for this moisture-dependent salamander's survival.
Where does Oaxacan Pigmy Salamander live?
Oaxacan Pigmy 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 Oaxacan Pigmy Salamander?
The main threats to Oaxacan Pigmy Salamander are 1.1, 2.1, 5.1, and 5.1.1. The full IUCN-classified threat record for this species is detailed on the species page.

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