Unveiling a Hidden World in the Atacama
In the world’s driest desert, a tiny reptile is rewriting a long-standing biodiversity puzzle. Scientists using cutting-edge genomic tools have revealed that the Garthia geckos, also known as Chilean marked geckos, are far more diverse than previously thought. What appeared to be a single, uniform species across the Atacama’s sun-bleached landscape is now recognized as a complex group that could include up to 11 distinct species. This revelation not only expands our understanding of biodiversity in extreme environments but also carries important implications for conservation amid climate change and habitat loss.
From Morphology to Molecules: The Genomic Breakthrough
The study, led by Kamryn Carter of the University of Wollongong (UOW), employed comprehensive genomic analyses to examine both mitochondrial and nuclear DNA across the geckos’ entire geographic range. While traditional approaches based on appearance suggested only two species—Garthia gaudichaudii and Garthia penai—the latest work shows deep genetic divergences that date back roughly 20 million years. Two populations that look almost identical can harbor distinct evolutionary histories, a phenomenon cryptic to the naked eye but clear in the genome.
“Historically, Garthia geckos were considered two species based on morphology, but a recent study looking at their colouration patterns suggested there was only one species, which means they appeared identical to the naked eye,” explained Kamryn Carter, a PhD candidate in UOW’s Environmental Futures Research Group. “Using modern genomic methods we uncovered hidden diversity. We found large genetic differences between geographically distinct populations, suggesting cryptic species.”
The Atacama: A Laboratory for Evolution
The Atacama Desert, renowned for its relentless sun and extreme aridity, provides a natural laboratory for studying adaptation. The geckos have weathered harsh temperature swings and scarce water resources, raising questions about how physiological and genomic changes drive survival in such conditions. The discovery that multiple cryptic species share the same geography suggests that microhabitat variation and historical climate fluctuations shaped diversification in this harsh setting.
Dr. Damien Esquerré, a co-author from UOW, emphasizes the broader significance: “Traditional approaches often overlook cryptic species, underestimating biodiversity and limiting our ability to conserve these unique lifeforms. South America is home to a wealth of threatened species, yet many regions, including the Atacama, remain underexplored at the genomic level.”
Implications for Conservation and Biodiversity Monitoring
Recognizing cryptic diversity alters how we measure biodiversity and prioritize conservation. If up to 11 species occupy the Atacama, each lineage may have unique ecological roles and distinct responses to climate stress. This means conservation strategies must consider genetic diversity, population structure, and local adaptation to ensure that protections cover the full spectrum of evolutionary lineages rather than a single, misrepresentative species label.
Moreover, the study underscores the value of integrating modern genomics into biodiversity surveys. In regions sensitive to climate shifts, genomic data can identify at-risk populations sooner, guiding habitat preservation efforts and informing management plans that aim to maintain evolutionary potential and ecosystem resilience.
Looking Ahead: What the Findings Mean for Desert Biogeography
The research team’s conclusion—that there may be at least two, and possibly up to 11 species of Garthia geckos—invites a re-examination of desert biogeography in South America. It highlights how species boundaries can be porous when viewed through the lens of morphology, and how genomes can reveal a hidden tapestry of life waiting to be understood. The work also invites further exploration of other Atacama fauna, where cryptic diversity may be widespread yet largely unrecognized.
About the Research
The study, “Hidden diversity in the driest desert on Earth: genomics unveils cryptic diversity in an ancient South American gecko lineage (Phyllodactylidae, Garthia),” was conducted by Kamryn Carter, Claudio Reyes-Olivares, Jonathan Eubanks, Hayden Hanna, Stuart Nielsen, and Damien Esquerré, and published in Molecular Phylogenetics and Evolution. The team included collaborators in Chile and the United States and relied on state-of-the-art genomic methods to reconstruct the geckos’ evolutionary history across their range.
These findings demonstrate how even the most unassuming creatures—hidden in one of the world’s harshest environments—can carry a rich genetic legacy, poised to inform conservation science for years to come.
