Lizards are fascinating creatures, with a world history going back 200 million years, when their ancestors roamed the Earth. Today there are more than 4,600 types of lizards, and the discoveries keep coming. In 2012, scientists found what may be the smallest lizards identified yet.
Sphaerodactylus Ariasae, or Jaragua Lizard
In 2001, scientists discovered a tiny lizard on a tiny island off the coast of the Dominican Republic. The Jaragua lizard measures about three quarters of an inch in length, or 16 millimeters, from the tip of his snout to the base of his tail. To get a good idea of just how small this fellow is, picture a dime with the lizard curled up around its perimeter.
As tiny as the Jaragua lizard is, he does not hold the record for the smallest lizard. In 2012, researchers discovered four new species of leaf chameleons that are roughly the same size and even smaller than the Jaragua. All four newly discovered species -- Brookesia confidens, Brookesia desperata, Brookesia micra and Brookesia tristis -- were found on the island of Madagascar. If you learned of this discovery on the news, you likely saw pictures of a juvenile chameleon sitting on a match head, underscoring just how tiny these guys are. Though the Brookesia lizards are similar in appearance, don't think they're the same. Scientists conducted DNA analysis and found that all species had deep genetic differences.
Can They Get Any Smaller?
Researchers may uncover a species even smaller than the leaf chameleons, but it's more likely we've approached the diminutive limit. As one scientist explained, as an animal gets smaller, its surface area accounts for a larger percentage of its body mass. At some point, it becomes impossible to get any smaller. Scientists believe that lizards, who live in dry environments surrounded by relatively moist leaf litter, could rapidly shrivel up and die -- their relatively large surface area would force them to evaporate when exposed to warm, dry air.
You may have noticed that the smallest lizards reside on islands. "Island dwarfism" is a term used by scientists to describe why a species becomes smaller over time to adapt to a restricted environment, such as an island. Smaller animals require fewer resources for survival, which is important to those living on islands and other areas with limited resources. The leaf chameleons in Madagascar confine themselves to a very small territory, as little as half a square mile. Because they're restricted to such a small area, any disturbance to their habitats can have significant consequences. Habitat conservation can mean life or death for these tiny reptiles.
- Global Animal: World’s Smallest Reptile Discovered
- BBC: Tiny Lizards Found in Madagascar
- Penn State Science: World's Smallest Lizard Discovered in the Caribbean
- PLOS One: Rivaling the World's Smallest Reptiles: Discovery of Miniaturized and Microendemic New Species of Leaf Chameleons (Brookesia) from Northern Madagascar
- San Diego Zoo: Reptiles: Lizard