Untangling Chaco Tortoise Taxonomy

Conservation Genetics Project

Genomics to clarify species boundaries and conservation units

The Chaco Tortoise (Chelonoidis chilensis) ranges across the Monte and Dry Chaco ecoregions of Argentina, Paraguay, and Bolivia—landscapes that differ dramatically in climate, vegetation, and environmental pressures. Species with wide distributions and limited mobility often become genetically structured across such environments, yet these differences do not always translate into visible physical traits.

For decades, scientists have debated whether Chelonoidis chilensis represents a single species or several. Morphological studies and early genetic analyses have reached conflicting conclusions, and most research has focused only on Argentina. Recent mitochondrial data hint at two deeply divergent groups corresponding to the Monte and Dry Chaco, but mitochondrial DNA alone cannot reliably resolve species boundaries.

This project uses whole-genome sequencing to clarify the evolutionary structure of the Chaco Tortoise across its full range. We aim to identify whether distinct lineages exist, evaluate how they relate to habitat differences, and assess whether they show signs of local adaptation.

Understanding these patterns is essential for conservation. The Chaco Tortoise is threatened by habitat loss and wildlife trafficking, and defining clear conservation units will help guide management decisions—including ensuring that confiscated individuals are released back into the correct region of origin.

Key Species

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