Some people might travel to tropical islands to discover new species. Not Jeremy Feinberg.
The Brooklyn-based ecologist found a species of frog that was brand-new to science right in New York City.
The recently discovered frog is known colloquially as the Atlantic Coast leopard frog and more formally as Rana kauffeldi. It is only the second time a new frog has been reported in the U.S. and Canada since 1986. The last time a new amphibian was described in New York or New England was in 1882.
Feinberg first encountered the Atlantic Coast leopard frog six years ago. At the time, he was trying to figure out why the population of southern leopard frogs had recently disappeared from Long Island as part of his PhD research at Rutgers University. He got a tip that there were still some southern leopard frogs in Staten Island, so one cool, rainy spring day he went to look for them.
The timing was key. It was early spring, right around the time of the first thaw, when male frogs sing to attract the ladies. Southern leopard frogs have a very distinct call: “chuck, chuck, chuck, chuck, chuck.” But that night Feinberg heard something that sounded like this: “Chuck. (Pause) Chuck. (Pause) Chuck.”
“Probably within 10 seconds my friend and I were both like, ‘Are you hearing that?’ ” he said. “We knew they were leopard frogs, but the call was way off.”
It was not immediately obvious that he had stumbled on a new species, however, because the frog making the funky call looked identical to the southern leopard frog that Feinberg knew so well.
So Feinberg teamed up with Catherine Newman, a biologist who was working at UC Davis. She was able to compare the genetic material of the frog that made the single-pulsed call with the one that made the multisyllabic call. About a year after Feinberg’s spring night on Staten Island, Newman sent him an email that read something like -- “Holy cow! You are right!”
FOR THE RECORD
Nov. 17, 1:07 p.m.: An earlier version of this article said Catherine Newman was working at UCLA when Jeremy Feinberg first contacted her. She was working at UC Davis.
Feinberg had just found a new species of frog, in the middle of one of the largest metropolises on Earth.
A paper describing that initial genetic work came out in 2012, but this week, Feinberg, Newman and other colleagues published a second paper on the frog in the journal PLOS One. The new paper includes a detailed examination of the frog’s call, its morphology and its range, which researchers now know stretches from central Connecticut and northern New Jersey down to North Carolina -- mostly along the I-95 corridor.
No one knows exactly how the Atlantic Coast leopard frog defied detection for so long, but Feinberg has a few ideas. For one, it is a “cryptic species,” meaning it looks nearly identical to another species, in this case the southern leopard frog. Scientists now know that the two species have a slightly different pattern of markings on their hind legs, but it would still be difficult to say conclusively that the two are entirely different species without genetic analysis.
Also, while the Atlantic Coast leopard frog’s range stretches for almost 500 miles, it is also narrow and fragmented. Finally, it has a particularly short season when it makes its distinctive mating call.
The Atlantic Coast leopard frog is medium-sized as frogs go. Its skin can look minty green or dark olive, depending on the light, and it has dark spots on its legs and back. It lives in grassy meadows and marshlands.
“They don’t need a pristine habitat, but they need a lot of land,” Feinberg said.
For example, there is a large population of the frogs in the New Jersey Meadowlands.
Back in 1936, a herpetologist named Carl Kauffeld proposed that there could be a third species of leopard frog in the Tri-State area that was neither the northern leopard frog nor the southern leopard frog. But he stopped short of naming it or describing it.
To honor Kauffeld’s hunch, which proved to be accurate, Feinberg named the frog after him -- Rana kauffeldi.
“It seemed a fitting way to give him what he deserved back then,” Feinberg said.