Soon, the latest cohort of graduates from the Museum’s Richard Gilder Graduate School—the first Ph.D.-degree-granting program for any museum in the Western Hemisphere—will receive Doctor of Philosophy degrees in Comparative Biology at a commencement ceremony in the Milstein Hall of Ocean Life. We're profiling these new Ph.D.s in the weeks surrounding commencement, and today we introduce Andre Carvalho. See our previous profiles of Carly Tribull, Phil Barden and Eugenia Gold.
Growing up in Rio de Janeiro, Andre Carvalho was not always interested in biology—at least not consciously. “It’s so peculiar,” he muses, “when you grow up in Brazil, biodiversity surrounds you, but you may not notice it that much.”
Yet the country’s biological richness was, in retrospect, hiding in plain sight: a friend’s yard might hold fruit trees, for instance, from which you could pick at will.
Throughout his youth, Carvalho had studied hard—his mother promoted academics above all—and was interested in most topics, from history to art to technology. But it wasn’t until college that he realized studying biology would meld all of his interests—he could hone his writing; study the history of life; immerse himself in the beauty of nature; and more.
In college and graduate school, where he received a bachelor’s degree in biology and a master’s degree in zoology, he specialized in the study of lizards. Then Carvalho took up teaching. He taught science for five years in a struggling public high school where he and other teachers helped double the students’ success rate on the national exam.
Having traveled little during his youth, Carvalho hoped to study for the Ph.D. degree in another country, and when he learned about the Museum’s Richard Gilder Graduate School (RGGS), he was sold. Waiting on tenterhooks to hear whether he had been admitted, he received his email of acceptance on the final day of Carnivale, Rio’s biggest and most famous celebration.
“It was amazing, almost surreal,” he recalls.
While at RGGS, Carvalho was supported by a prestigious fellowship from the Brazilian government for his study of lizards, and worked with advisor Darrel Frost, an expert in amphibian and lizard systematics. Carvalho decided to focus on the evolutionary relationships of the Tropiduridae family of lizards, which dwell in many habitats across South America, and are some of the most common and widespread of all reptiles on the continent.
Undertaking extensive fieldwork for his thesis research, Carvalho traveled for six months and trekked thousands of miles through Argentina, Bolivia, Paraguay, and his home country, Brazil. With a chartered airplane, he often searched for lizards in places no scientist had ever been before. “I went to the end of the world to sample my lizards,” he says.
During those months, he observed hundreds of specimens, collecting new species and often observing novel traits among the family. For instance, within one lizard genus he found cases of sexual dichromatism, meaning that the females rather than the males are the more gaudily colored sex, a trait often linked with assertive courtship display in males. Do these brightly hued female lizards demonstrate the same behaviors? Carvalho doesn’t yet know, but he hopes to find out during the next phase of his academic career.
For his doctoral dissertation, Carvalho integrated morphological comparisons and DNA data to revise the evolutionary tree of relationships within the family. “Systematically," he says, “it’s not as well resolved as was thought.” But Carvalho’s analyses of more than 1,000 specimens provide the best picture yet of the ancestry and evolutionary history for this important lizard group.
After graduation from RGGS, Carvalho will return to Brazil. He intends to continue seeking answers to his questions about tropidurid lizards. And he plans once again to teach—perhaps graduate students this time around—so that he may pass along the methods he has learned at the Museum to budding scientists.
“It’s time,” he says, “for me to give back.”