Phymaturus

A remarkable group of lizards found mainly in Argentina and Chile, and they stand out as some of the most specialized reptiles in South America. Often called rock lizards, members of this genus are perfectly adapted to life in the rugged, rocky habitats of the Andes and surrounding regions. Unlike many lizards that dart around open ground, Phymaturus species are sit-and-wait specialists, spending much of their time basking on sunlit rocks, soaking up warmth, and retreating quickly into crevices when threatened. Their flattened bodies, rough scales, and muted earthy colors make them blend seamlessly with their rocky environments, acting as natural camouflage.

Their dietary specialization and reproductive strategy make the genus Phymaturus truly unique among lizards. While many lizards are opportunistic feeders that eat insects, Phymaturus species are primarily herbivores, feeding on leaves, flowers, and seeds. This is unusual in the reptile world, where strict herbivory is relatively rare. To handle such a diet, they have complex digestive systems and spend a lot of time basking to help process tough plant material. On top of that, unlike many reptiles that lay eggs, Phymaturus lizards are viviparous, meaning they give birth to live young. This adaptation is especially important in the cold, high-altitude environments they inhabit, where eggs might not survive low temperatures or unpredictable weather.

These lizards grow slowly, live for decades, and reproduce at a much lower rate compared to other reptiles. Instead of producing large clutches of eggs every year, females typically give birth to only a few offspring after long gestation periods. This “slow and steady” approach is well-suited to the stable but harsh mountain habitats they call home, but it also makes them more vulnerable to environmental changes and habitat destruction. Their populations are often isolated in rocky patches, meaning each group is adapted to its own little corner of the Andes, and some species have very restricted ranges.