Swamp Stomp

Volume 14, Issue 44

In 2009, Jeremy Feinberg, an ecologist at Rutgers University, and his team—consisting of Louisiana State University geneticist Catherine Newman, University of Alabama biologist Leslie Rissler, University of California, Los Angeles biologist Brad Shaffer, and fellow Rutgers ecologist Joanna Burger—happened upon an unusual frog call while exploring the disappearance of the southern leopard frog from the New York City area. The chuck, chuck, chuck sound emanating from a group of frogs on Staten Island differed from any known species in the area. When describing this first encounter of the frog call, Feinberg said, “Pretty much within 10 seconds of hearing the call, we said, ‘Something is really weird here.’” That chance meeting led to Feinberg and his team investigating the origins of the odd sound.

January 2012 saw the team publish their findings in Molecular Phylogenetics and Evolution. This initial publication, however, had an extremely narrow subject matter. It focused on the genetic uniqueness of the unknown amphibian, which until that point had been confused for a southern leopard frog.

On October 29, 2014, a further study was published in PLOS ONE, whereby the team argued that the uniqueness of the frog ought to designate a new species. The scientists then opted to name the frog after Carl Kauffeld, a herpetologist who in 1936 stipulated that New York City was home to not only the two accepted species of leopard frogs, but also a third. Rana kauffeldi, then, became the latest of the 19 species of leopard frog known worldwide.

There are two aspects of Rana kauffeldi that differentiate it from other species of leopard frogs: the croak and the spots found down the back of the legs. The croak, however, is the most revealing characteristic. The team described the croak as a “single-note unpulsed chuck,” a sound that distinctly stands apart from the region’s other leopard frog species.

It is extremely difficult to hear the unique croak of Rana kauffeldi, however. The breeding period in which these mating calls occur only last for a few weeks each year, during which most noises are drowned out by the sound of the spring peepers. Feinberg said that these factors “keep them hidden.” He added, “You have to win the jackpot to hear them.”

Rana kauffeldi predominantly dwell within open-canopied costal marshes and bottomland floodplains located within a few miles of a river mouth. Feinberg said they can be found in “places where you can almost see and smell the ocean.” These habitats, however, are disappearing as a result of ever growing development. Once able to be found throughout the New York City area, Rana kauffeldi is now limited to Staten Island area where Feinberg first discovered them.

The habitats that still host the new species, however, are isolated from one another, and do not suggest the species may last in the long term. Feinberg said, “There’s one population in Staten Island where all it would take is filling in one pond, and it would be gone.” The optimistic view, however, is that Rana kauffeldi has managed to survive up to this point despite the restrictions that face their habitats, and the chytrid fungal disease that has caused mass amphibian annihilation elsewhere. Considering these obstacles that have already been overcome, it would be foolhardy to dismiss the longevity of the species.