Four new species of vibrantly colored lizards have been discovered in Brazil and Paraguay by André L. G. Carvalho, a recent graduate of the Museum’s Richard Gilder Graduate School. Published in two papers in the journal American Museum Novitates last month, the new research is a reminder that South America hosts many more species of reptiles waiting to be described.
The new species are all within the genus Tropidurus, a group of animals that contains a wide variety of species within it. Although Tropidurus lizards are ubiquitous throughout much of South America, much of the evolutionary tree of the genus is unknown. Using the Museum’s collections, Carvalho created a model of the geographical distribution of Tropidurus that enabled him to predict the regions of the continent most likely to harbor undiscovered examples of the genus. In 2013, his search for these species took him to Paraguay and the scrublands of Brazil, known as the Caatinga.
In the field, Carvalho was able to examine specimens, take hundreds of tissue samples for DNA analysis, and study the ecology of these lizards, as well as their coloration patterns, distribution, and behavior. He also studied hundreds of specimens housed in natural history museums throughout South America, using this information to determine where the lizards fit in the tree of life.
After analyzing the evolutionary relationships of Tropidurus, Carvalho was able to identify several new species, four of which are discussed in the recent publications. In the Caatinga, he discovered Tropidurus sertanejo. He named it for the people who live in the Sertão, the region where he found the lizard.
“Tropidurus sertanejo is differentiated from other species by its magnificent coloration,” Carvalho said. “The people are like the lizard – colorful, brave, and thriving. I admire them greatly and named the beautiful species in this way to honor them.”
He similarly honored the Paraguayan culture by naming the lizards discovered there using their indigenous language, Guaraní. Tropidurus teyumirim is the smallest lizard in its species group, so it was named for the words “teyu” and “mirim” which together means “little lizard.” Tropidurus tarara takes its name from "tarara," a Guaraní word describing someone who is restless. This refers to the complex communication system common to all Tropidurus lizards, which involves head shakes, body wiggles, and push-ups. Finally, T. lagunablanca was only found in a small area of the private nature reserve of Laguna Blanca, which is not much larger than the Museum itself.
The limited size of T. lagunablanca’s habitat and the number of species Carvalho discovered highlights the importance of environmental conservation in Eastern Paraguay. While the habitats of T. teyumirim and T. tarara are already conserved regions, T. lagunablanca is already in peril due to habitat loss caused by farming and cattle ranching. The discovery of these new species underlines the importance of protected natural reserves in understudied countries.