Team that includes A&M biologist discovers new species of salamander

Video: College of Science

Texas A&M University biologist Joseph Bernardo is part of a team of researchers that has identified a new species of salamander essentially hiding in plain sight among what was originally thought to be a common population of the small amphibians.

Bernardo and collaborators from Florida State University and the University of Southern Mississippi made the discovery during an extensive analysis of different populations of Desmognathus auriculatus salamanders, commonly referred to as Southern Dusky Salamanders throughout the coastal regions of the southeastern United States.

During their multi-year analysis, the team noticed subtle physical differences in one group of the salamanders found in the Louisiana-Mississippi region. After comparing the group’s genetic data with other populations of dusky salamanders, the team’s suspicions that they were observing an entirely new species were confirmed.

Details of their findings were published earlier this summer in the scientific journal Zootaxa.

“It’s pretty exciting,” said Bernardo, a member of the  Department of Biology faculty since 2011. “There are millions of species out there, and we have no idea how many we don’t even know about. Describing a new species for the first time is a very humbling kind of contribution to science.”

The new species is named Valentine’s Southern Dusky Salamander (Desmognathus valentinei) in honor of biologist Barry D. Valentine, faculty emeritus in the Department of Evolution, Ecology and Organismal Biology at Ohio State University who first suggested their distinctiveness in the early 1960s.

“Barry was so perceptive that he was able to see these very subtle differences which turned out to be differences between species,” Bernardo said. “In fact, they’re not even closely related to the southern dusky salamander.”

Although the physical and biological characteristics of dusky salamanders can differ geographically, Bernardo notes that they appear and behave strikingly similar at first glance. Much like its cousins further east, the Valentine’s Southern Dusky dwells in cool, muddy places along freshwater marshes and streams. Typically brownish-black in color, they measure anywhere from 6 to 8 centimeters in length and subsist on small worms and insects.

Upon closer inspection, however, the researchers were able to discern more apparent dissimilarities. The Valentine’s Southern Dusky has an overall larger body structure, and adults have nondescript dorsal markings unlike the crisply defined colored blotches found on many dusky salamanders. Their skulls have subtle distinctions, and their tails maintain a bladelike shape rather than narrowing to a fine tip.

In a follow-up study, Bernardo’s colleague observed that the southern dusky and the Valentine’s Southern Dusky even go so far as to avoid interbreeding.

“Once we had these many different kinds of data, it was clear these salamanders were from distinct evolutionary lineages,” Bernardo said. “It’s a species that nobody realized was there. Even if somebody were to walk through that area, they probably wouldn’t even know they were there. They’re basically these hard-to-find, quiet members of the environment.”

Approximately 30 species of dusky salamander inhabit North America. But even with the discovery of a new species, salamanders as a whole are declining. Since 1980, numerous studies have indicated an alarming dip in populations of amphibians in general worldwide.

Although additional research will be necessary in order to better determine the population density of the Valentine’s Southern Dusky, Bernardo says that, by all appearances, it seems to be thriving. And while there is still much to understand about this new species, he says the most important lesson is that there are still plenty of substantial discoveries to be made right here on Earth.

“We tend to think of discovery as going to the outer reaches of the solar system and landing on Mars,” Bernardo said. “I’m not saying we shouldn’t do that, but it’s amazing how little we know about the planet we live on. I think society as a whole should value that more.”

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