An international team of scientists has revealed a startling case of hidden biodiversity in one of the planet’s most hostile environments. Genomic research has confirmed that a small reptile known as the Chilean marked gecko, long considered to be just one or two species, actually represents a complex of up to 11 distinct species living in Chile’s Atacama Desert. The discovery, led by researchers at Australia’s University of Wollongong, dramatically revises the understanding of how life adapts and diversifies in extreme settings.
The finding is a prime example of “cryptic diversity,” where multiple species are mistakenly classified as a single one because they appear identical to the naked eye. By employing advanced genetic tools to analyze the geckos’ DNA, the researchers uncovered deep evolutionary divisions that morphology alone could not detect. This work not only rewrites the family tree for these resilient desert dwellers but also raises urgent questions about conservation, as what was presumed to be a widespread, single species is in fact a collection of potentially vulnerable and geographically restricted ones.
A Deceptive Uniformity
The geckos of the genus Garthia are small, unassuming lizards that have mastered survival in the driest non-polar desert in the world. For decades, herpetologists classified them based on physical characteristics like scale patterns and coloration. This traditional approach led to conflicting conclusions; while they were historically considered two species, a more recent study based on their color patterns suggested they were only one. This morphological similarity masked a much more complex reality.
The new research highlights the most dramatic example of this deception with two lineages, Garthia gaudiachaudii and Garthia penai. Visually, they are almost indistinguishable. Yet, the genomic data reveals they are not close relatives, having diverged from a common ancestor approximately 20 million years ago. This immense genetic gap between physically similar animals underscores the limitations of relying solely on observation to define a species and points to a history where different populations evolved similar traits independently to cope with the harsh desert environment.
Uncovering a Hidden World with Genomics
The breakthrough came from applying a modern scientific approach known as integrative taxonomy, which combines multiple lines of evidence to delineate species. While traditional morphology laid the groundwork, the definitive conclusions were drawn from the geckos’ genetic code.
From Tail Tip to Family Tree
The research, published in the journal Molecular Phylogenetics and Evolution, involved collecting tissue from gecko specimens across the Atacama. In a collaborative effort, a team at LSU Shreveport, including undergraduate students Jonathan Eubanks and Hayden Hanna, worked with the tips of gecko tails brought back from Chile. They meticulously extracted both mitochondrial and nuclear DNA from the tissue samples. After amplifying the DNA to create a sufficient quantity for study, a third-party facility sequenced the material.
The core of the discovery lay in analyzing this genetic data. Lead author Kamryn Carter, a Ph.D. candidate at the University of Wollongong, and her colleagues compared the DNA sequences from geographically separate populations. They found significant genetic differences, or mutations, that had accumulated over millions of years. By reconstructing the evolutionary history of the lizards, they revealed the ancient splits that gave rise to this hidden family of species.
Life in an Extreme Environment
The Atacama Desert is a landscape of extremes. As the driest place on Earth, it presents formidable challenges to life, with intense solar radiation, dramatic temperature fluctuations, and an overwhelming lack of water. The conventional wisdom was that such a harsh environment would support relatively low biodiversity. This discovery turns that assumption on its head, proving that the desert is home to far more unique species than previously recognized.
The existence of up to 11 distinct Garthia species suggests that the desert has not been a static barrier to life, but rather a dynamic landscape that has driven evolution. Over millions of years, isolated populations of these geckos likely adapted to specific microhabitats, such as rocky outcrops or sparse vegetation patches, slowly diverging into new species. This finding reshapes scientific understanding of how life can persist and specialize in the planet’s most challenging environments, highlighting the Atacama as an unexpected cradle of biodiversity.
An International Collaboration
This significant advancement in herpetology was the result of a coordinated international effort. The project was spearheaded by Kamryn Carter and biologist Dr. Damien Esquerré at the University of Wollongong in Australia. Their work was built upon a collaboration with Chilean colleagues and a vital partnership with researchers in the United States at LSU Shreveport.
Dr. Stuart Nielsen, an LSUS herpetologist, initiated his part of the research years ago after finding an opportunity to travel to Chile and connect with local scientists. His work, along with that of his undergraduate students, provided key genetic data that verified the species-level status of lineages that had never been sequenced before. According to Ms. Carter, using these modern genomic methods allowed the team to uncover the vast “hidden diversity” that simple observation had missed. Dr. Nielsen added that the findings demonstrate that “the desert is home to far more biodiversity than previously recognized,” emphasizing the importance of applying new technology to re-evaluate what we think we know.
Rethinking Conservation Strategies
The implications of this discovery extend far beyond taxonomy. From a conservation standpoint, recognizing a single, widely distributed species means there is little immediate concern for its survival. However, splitting that one group into 7 to 11 distinct species fundamentally changes the picture. Each of these new species likely has a much smaller, more restricted geographic range, making it significantly more vulnerable to threats.
Habitat loss and the growing impacts of climate change in the Atacama region could now pose a direct threat to the existence of multiple unique species that were previously unknown to science. As Dr. Nielsen stated, these findings “highlight the urgent need for up-to-date taxonomy and conservation.” Protecting the biodiversity of the Atacama Desert now means identifying the specific habitats of each of these cryptic gecko species and developing targeted strategies to ensure their survival. This research serves as a powerful reminder that there is still much to learn about the planet’s biodiversity, and that modern genetics are an essential tool in the race to understand and protect it.