By combining biological, physiological and environmental data, researchers gain new insights into how climatic factors have influenced the rate and extent of lizard evolution.
Michael Eisenstein
Miguel Vences
They live on windy mountain peaks, damp rainforests, and even the edge of the Arctic. Now, a multinational team has identified temperature as an important driver of the evolution of lizards from the lacertid family. Their findings indicate that warm-adapted species have historically achieved a level of genetic diversification that allowed them to spread and eventually adapt to the cooler, temperate ecological niches where they are most heavily represented. In contrast, low temperature adapted species remained more geographically constrained and specialized. Their findings also suggest that this adaptation may have produced physiological vulnerabilities that could put certain species at risk on a warming planet.
“I wanted to better understand what determines the distribution range of species,” says Miguel Vences, of the Braunschweig University of Technology in Germany. He and Katharina Wollenberg Valero, of the University of Hull, assembled a team of collaborators from around the world, including Morocco’s Cadi Ayyad University, to profile key biological characteristics from 262 lacertid species and assess the impact of climatic factors on their evolution.
Based on extensive genomic data, the researchers reconstructed key milestones in the history of this family, clarifying the timetable over which these species emerged and revealing close connections between seemingly disparate lizards. “We resolved many controversial nodes in the lacertid tree,” says Vences.
They then coupled these genomic data with species-specific physiological metrics, such as preferred body temperature, and climatologic data to assess how individual species have adapted to distinct environmental niches. Their results indicate that temperature and humidity strongly influenced evolution, with rapid diversification in warmer climes giving rise to species that subsequently spread and adapted to temperate ecosystems. In contrast, Vences notes that “lizards from cool areas had smaller distribution ranges and slower genetic evolution.” These low temperature environments also appear to have contributed to physiological adaptations that have allowed these lizards to thrive under cooler conditions than most other members of the lacertid family.
Martha Muñoz of Yale University notes that the team’s multipronged analysis has yielded intriguing correlations between climate and speciation, which merit further exploration with more intensive mechanistic studies of how different lacertid lineages have adapted to their ecological niches. She finds the insights into the evolutionary history of the myriad temperate lacertid species particularly interesting. “There’s been a lot of focus on tropical lizards,” says Muñoz. “But this team has taken a different tack and found that climatic environment is just as important for influencing the tempo and mode of diversification in temperate regions.”
The authors speculate that this process of temperature-driven adaptation could come at a high price. Their results indicate that species that have evolved to thrive in relatively ‘extreme’ tropical or cooler habitats may have little capacity for adapting to further shifts in temperature. Based on these limitations, the researchers hypothesize that this may potentially put these lizards at risk in the era of anthropogenic climate change.
doi:10.1038/nmiddleeast.2019.133
