"There are northern and southern leopard frogs in that general area, so I was expecting to find one of those that for some reason had atypical behaviors or that were hybrids of both," Newman said.
"I was really surprised and excited once I started getting data back strongly suggesting it was a new species. It's fascinating in such a heavily urbanized area."
Feinberg suspected that the leopard-frog look-alike with the peculiar croak was a new creature hiding in plain sight.
Instead of the "long snore" or "rapid chuckle" he heard from other leopard frogs, this frog had a short, repetitive croak.
As far back as the late 1800s, scientists have speculated about these "odd" frogs.
"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 on sight. Thanks to molecular genetics, people are picking out species that would otherwise be ignored."
The results were clear-cut: the DNA was distinct, no matter how much the frogs looked alike.
"If I had one of these three leopard frogs in my hand, unless I knew what area it was from, I wouldn't know which one I was holding because they all look so similar," Newman said. "But our results showed that this lineage is very clearly genetically distinct."
Mitochondrial DNA represents only a fraction of the amphibian's total DNA, so Newman knew she needed to do broader nuclear DNA tests to see the whole picture and confirm the frog as a new species. She performed the work at UC Davis.
Habitat destruction, disease, invasive species, pesticides and parasites have all taken a heavy toll on frogs and other amphibians worldwide, said Rissler, currently on leave from the University of Alabama and a program director
|Contact: Cheryl Dybas|
National Science Foundation