CR

Rio Spinythumb Frog

Crossodactylus grandis

Unknown

Overview

Crossodactylus grandis, or the Bahia spinythumb frog, is a species of frog in the family Hylodidae. It is endemic to Brazil. Its natural habitats are subtropical or tropical high-altitude grassland and rivers. It is known solely from the Parque Nacional do Itatiaia in Minas Gerais in Brazil, where it lives in cloud forests. It is threatened by habitat loss.

Crossodactylus grandis faces severe population decline primarily due to habitat destruction from urban expansion and agricultural conversion in Brazil's Atlantic Forest region. The species' dependence on pristine stream environments makes it particularly vulnerable to water pollution and sedimentation from nearby human activities. Climate change compounds these pressures by altering precipitation patterns that affect the rocky stream habitats essential for this frog's reproduction and survival.

Threat summary

Habitat

This species inhabits rocky streams and adjacent riparian forests within Brazil's Atlantic Forest biome, typically found in areas with fast-flowing water and boulder-strewn creek beds. It requires pristine aquatic environments with stable water flow and minimal human disturbance for successful breeding and larval development.

Forest· majorForest - Subtropical/tropical moist lowland· majorRocky areas· major

Conservation measures underway

Species managementSpecies recoveryEx-situ conservation

Other threatened species in HYLODIDAE

EN

Crossodactylus timbuhy

Unknown
VU

Crossodactylus werneri

Declining
CR

Crossodactylus boulengeri

Unknown
EN

Hylodes perere

Declining

Frequently asked questions

Why is Rio Spinythumb Frog classified as Critically Endangered?
Rio Spinythumb Frog 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. Crossodactylus grandis faces severe population decline primarily due to habitat destruction from urban expansion and agricultural conversion in Brazil's Atlantic Forest region. The species' dependence on pristine stream environments makes it particularly vulnerable to water pollution and sedimentation from nearby human activities. Climate change compounds these pressures by altering precipitation patterns that affect the rocky stream habitats essential for this frog's reproduction and survival.
Where does Rio Spinythumb Frog live?
Rio Spinythumb Frog occurs in across multiple regions. Country-level distribution data is sourced from the IUCN Red List and cross-referenced with GBIF occurrences.
What are the main threats to Rio Spinythumb Frog?
The main threats to Rio Spinythumb Frog are 2.3, 5.3, 8.1, and 8.2. The full IUCN-classified threat record for this species is detailed on the species page.

Get weekly conservation intelligence

One short digest a week of the most striking species and country data we ship, plus breaking conservation news paired with our database where it matters.

Free, no spam. One-click unsubscribe in every email.