In the Peruvian Andes, a lizard claimed the title of highest altitude reptile in the world. The lizard was seen up to 5,400 meters above sea level, exposed to icy temperatures, intense ultraviolet radiation and low oxygen, researchers reported on February 15 in Herpetozoa.
In October 2020, zoologist José Cerdeña and his colleagues ascended Peru’s Chachani volcano, which rises to 6,057 meters above sea level. The team searched for Liolaemus lizards, also known as tree iguanas, and found them when investigators climbed above 5,000 meters.
“We observed that something was moving between the rocks,” says Sardinia, of the National University of San Agustín in Arequipa, Peru. "At first we thought they were mice." After taking a closer look, he and his team saw that the throwing animals were actually lizards, tentatively identified as Liolaemus tacnae. The species is known to survive in high altitude areas in Peru, and at least one population near Chachani has been previously seen at about 4,000 meters above sea level.
Survival in such prohibitive conditions is hard enough for mammals (SN: 29/07/20). But cold-blooded reptiles face additional obstacles in temperature regulation, so records of such high reptiles are rare. Until now, the tallest living reptile was a species of cold-resistant agama lizard (Phrynocephalus erythrurus) that lived on the Tibetan Plateau at 5,300 meters. The Andean lizard breaks the old record in 100 meters.
It is somewhat appropriate that the record be for a species of lizard Liolaemus. The genus is exceptionally diverse, with more than 270 species adapted to a wide range of habitats throughout South America.
Climate change could have eased Liolaemus' record condition, Sardinia points out, as colder conditions receded over the mountain tops in the face of warming. “It is possible that this species of lizard began to colonize this altitude recently,” he says.
The next steps of the research group are to verify the identification of the lizard with physical and genetic analysis, says Sardinia. You also want to know more about reptile physiology, which can keep secrets for your high altitude lifestyle.