Geckos living in the driest place on Earth stump scientists

The Chilean marked geckos that call Chile’s Atacama Desert home have proved annoyingly difficult to classify. While one might assume that different species simply look different from each other, that’s not always the case. Currently, Chilean marked geckos, also known as Garthia geckos, officially consist of two species—Garthia gaudichaudii and Garthia penai. However, different researchers have proposed more or even suggested that only one species exists within the genus Garthia. 

To try and settle the matter, a team of researchers have conducted a genomic investigation into the elusive reptiles that live in the driest place on Earth and reconstructed their evolutionary history. While their study challenges the suggestion that Garthia geckos might all belong to the same species, it doesn’t exactly solve the mystery. The results of their analysis indicate that there are at least two species—the previously mentioned G. gaudichaudii and G. penai—but there could be as many as 11. 

“For the first time, we used phylogenomic and population genetic methods to better understand diversity across the entire distribution of Garthia,” the researchers wrote in the study, published in Molecular Phylogenetics and Evolution. “Our phylogenetic analyses reveal deep evolutionary divergence strongly supporting the existence of at least the two nominate species,” though they also found “evidence supporting a cryptic species complex of between three and eleven species.” 

Cryptic species are organisms that look identical, but their genetics are different enough to be considered different species. For example, the researchers found that the similar looking G. gaudichaudii and G. penai genetically diverged 20 million years ago. 

“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,” Damien Esquerré, a co-author of the study and an evolutionary biologist at the University of Wollongong, said in a statement. 

The study goes to show that scientific tools are revealing some of nature’s most elusive secrets, but certainly not all of them.