Undescribed Lithobates from New York & New Jersey

Hiding in Plain Sight: Rutgers Scientist Discovers New Frog Species in New York and New Jersey

In New York City – in the midst of some of the world’s tallest skyscrapers – and within view of the Statue of Liberty, scientists have found a new frog species.

While discovering new species in remote rainforests is common, finding this one in the ponds and marshes of Staten Island, mainland New York, and New Jersey was a big surprise to the scientists from Rutgers University, UCLA, UC Davis, and the University of Alabama who worked together to make the discovery .

The yet unnamed frog – which biologists historically mistook for a more widespread variety of the leopard frog — may even extend into parts of Connecticut and extreme northeastern Pennsylvania. Researchers believe that these are likely the same leopard frogs that completely disappeared from Long Island and other parts of the area over the last few decades.

“It is very surprising for a new species like this to have been unrecognized in this area until now,” said Rutgers doctoral candidate and guest researcher at Brookhaven National Laboratory Jeremy Feinberg, who made the initial discovery. “Their naturally limited range coupled with recent unexplained disapperances from places like Long Island underscores the importance of this discovery and the value that conservation efforts might have in the long-term survival of this urban species.”

In newly released research, available online in the journal Molecular Phylogenetics and Evolution, scientists used mitochondrial and nuclear DNA data to compare the new frog to all other leopard frog species in the region and determined that it is an entirely new species, soon to be named by the researchers. The wetland species likely once lived on Manhattan, and though it’s now only known to live in a few nearby locations, Yankee Stadium would probably be the bull’s-eye of a target drawn around its current image.

Feinberg, co-author of the study, is working on his doctoral thesis in the School of Environmental and Biological Sciences. He was doing research on the alarming decline of leopard frogs in the wetlands of New York and New Jersey when he noticed that the regional leopard frogs displayed unusual behaviors and peculiar croaks. Instead of the “long snore” or “rapid chuckle” he heard from other leopard frogs, this frog had a short, repetitive croak.

“When I first heard these frogs calling, it was so different, I knew something was very off,” Feinberg said. “It’s what we call a cryptic species: one species hidden within another because we can’t tell them apart by looking. But thanks to molecular genetics, people are really picking out species more and more that would otherwise be ignored.”

To find out if his hunch was right, Feinberg developed a partnership with Cathy Newman, a geneticist who was completing a master’s degree in genetics at the University of Alabama.

The two decided to team up on the project after Newman, who was working on an unrelated study of leopard frogs, asked Feinberg, an ecologist and regional amphibian and reptile expert, for assistance with her research. In this heavily urbanized area Newman expected the frogs to be either of two previously known species, or perhaps a hybrid of both at best. What she found turned out to be a totally new species.

“I was very confident that the genetic results were going to support the idea that this was a new species” Feinberg said. “As far back as the late 1800s scientists have speculated about the odd frogs but until the advent of molecular genetics, it was difficult to prove anything.”

Although the frogs were discovered in the New York, New Jersey metropolitan area, the bulk of the genetics research took place at UC Davis. The results of those “unusual frogs” whose weird sounding calls were different from leopard frogs were clear-cut: the DNA was distinct, no matter how much the frogs looked alike.

What this discovery proves, said Joanna Burger, professor in the Department of Cell Biology and Neuroscience in the School of Arts and Sciences, and Feinberg’s advisor on the project, is that even in densely-populated urban areas new species can be found. Because of the extensive extinctions over the last few decades from habitat destruction, disease, invasive species, pesticides and parasites, it is even more imperative that conservation concerns be addressed, Burger said.

“It is amazing to discover a new frog in Rutgers backyard and the metropolitan area of New York and New Jersey that was among us for a century without being recognized,” Burger said. “We need to do all we can to make sure that we protect it.” 

Catherine E. Newman, Jeremy A. Feinberg, Leslie J. Rissler Joanna Burger, & H. Bradley Shaffer. 2012. A new species of leopard frog (Anura: Ranidae) from the urban northeastern US. Molecular Phylogenetics and Evolution 63, 445–455.

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