Edward Stanley: Evolution of Armor in Girdled Lizards

by AMNH on

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There are only 12 species of reptiles and amphibians native to Great Britain.

Edward Stanley did his best to catch them all during his childhood in the Dorset countryside.

So it may be no surprise that Stanley, a member of the second entering class (2009) in the Comparative Biology doctoral program at the Richard Gilder Graduate School, continues to collect and study these animals.

Ed Stanley with Smaug giganteus
Ed Stanley face to face with a sungazer lizard (Smaug giganteus) in Mpumalanga, South Africa 
© AMNH/E. Stanley

Stanley’s dissertation focuses on the evolution of armor in the Cordylidae, a family of diverse girdled lizards in southern Africa. The lizards’ armor is actually made of tiny bones embedded in their skin, called osteoderms, which are thought to protect the animals from attacks by predators.

“I worked on the evolutionary relationships of this group during my master’s degree, and the more I learned about them, the more interesting questions came to mind,” Stanley said. “It was amazing to me how little was known about these fascinating animals, and so I decided to delve deeper into their evolution.”

Osteoderms are embedded into the lizard’s skin, not attached to the skeleton. To measure and analyze the variation in these bony plates of armor in place, Stanley used high-resolution X-ray computed tomography (CT) in the Museum’s Microscopy and Imaging Facility. He took full-body scans of the more than 80 living and extinct species in the family. Stanley found that these lizards underwent a period of rapid diversification during the Oligocene-Miocene boundary, about 23 million years ago, a diversification linked to ecological adaptation.

CT Scan of Smaug giganteus (Ed Stanley, RGGS)
This computed tomography (CT) scan show’s the “osteoderms”—bony plates of armor—of Smaug giganteus. Ed Stanley uses these features to investigate shifts in ecology within this morphologically diverse family of lizards. 
© AMNH/E. Stanley


Stanley also described a new species of girdled lizard, Cordylus marunguensis, found in the mountains of central Africa, and revised the taxonomy of the family, naming several new genera, including Smaug—for their resemblance to mythical dragons—and the tail-biting Ouroborus.

Ed Stanley Tortoise RGGS
 Edward Stanley helping a leopard tortoise cross the road in the Western Cape, South Africa. 
© AMNH/E. Stanley


Stanley, whose RGGS advisor was Dr. Darrel Frost, conducted fieldwork throughout southern Africa, including South Africa, Lesotho, and Swaziland, where collecting lizards wasn’t always risk-free, involving climbing waterfalls, avoiding venomous snakes, and dealing with rapid weather changes.

“In Lesotho, we had to quickly get to lower ground as a giant lightning storm rolled in,” Stanley said. “It was pretty scary because we were walking around on one of the highest points in southern Africa—with metal crowbars tied to our backs!”

Stanley received his bachelor’s degree in zoology from the University of St. Andrews in Scotland and his master’s degree in biology from Villanova University. He successfully defended his Ph.D. dissertation on September 5, 2013. Stanley will continue his research on African reptiles and amphibians as a postdoctoral researcher at the California Academy of Sciences.

On September 30, 2013, the first graduates of the Richard Gilder Graduate School will receive Doctor of Philosophy received degrees in Comparative Biology at the inaugural commencement for the program, the first Ph.D.-granting program for a museum in the Western hemisphere. We profile the newly minted Ph.D.s:

John Denton | Bryan Falk | Antonia Florio | Shaena Montanari | Edward Stanley | Isabelle Vea