Biologists Create Squamate Reptile Family Tree
May 9, 2013

Mapping The Squamates

Michael Harper for — Your Universe Online

Those feeling as if there had been something missing in this world can rest easily tonight: A George Washington University (GWU) biologist and a team of researchers have finally finished the first large-scale evolutionary tree of every known squamate in the world.

Squamates are reptiles such as snakes and larger lizards. This project had been underway since 2008, but according to GWU the last five years have been particularly intense as the final product drew closer. Until now, there had been no solid evolutionary tree to tie these large reptiles together in one tree. Though biologists knew on a basic level that they all belonged to the larger reptilian family, they were unable to determine the exact relationship between specific animals in this family. Now, thanks to Alex Pyron, the Robert F. Griggs Assistant Professor of Biology in GW´s Columbian College of Arts and Sciences and researchers from City University of New York and Arizona State University, future biologists will be able to access this family tree of more than 4,000 species of reptiles.

“Squamates include all lizards and snakes found throughout the globe, including around 9,500 species on every continent except Antarctica, and found in most oceans,” explains Dr. Pyron in a press statement heralding his achievement.

“This is everything from cobras to garter snakes to tiny geckos to the Komodo Dragon to the Gila Monster. They range from tiny threadsnakes that can curl up on a dime to 10 feet monitor lizards and 30 foot pythons. They eat everything from ants to wildebeast.”

His family tree isn´t yet perfect, of course. There are still several holes and gaps in his squamate family tree, but Dr. Pyron says the resulting map is a good start towards mapping each and every genus and species in the world. He equates mapping these species to completing a family tree based on a series of guesses.

“It´s like building an incomplete family tree for your family, but with half of the ℠children´ sampled. You´re in it, but not your brother, one of your cousins is, but not another. However, because it´s so complete, we know where the missing relatives go because there´s no longer as much mystery as to how the missing species, or cousins, are related, with a few notable exceptions for some remaining species,” explained Dr. Pyron.

The biologist also mentioned this work is a community effort, necessitating the endeavors of many people with access to many databases to fill in the empty spaces.

This work has been ongoing since 2008 and was funded by a grant from the National Science Foundation Postdoctoral Research Fellowship in Biological Informatics. Without it, future biologists might not know how to classify a newly discovered species or interpret the moves and behaviors of another species based on their relatives.

For instance, if a biologist knows a certain lizard likes to hide during the day, then they can infer a newly discovered lizard in the same genus might also prefer to lay low during the day.

“We have laid down the structure of squamate relationships and yet this is still the beginning,” said Dr. Pyron in closing.

“As hundreds of new species are described every year from around the glove, this estimate of the squamate tree of life shows us what we do know, and more importantly, what we don´t know, and will hopefully spur even more research on the amazing diversity of lizards and snakes.”