Even in one of the most densely populated places on Earth, nature is still capable of some big surprises. Biologists have described a new species of leopard frog discovered in New York City.

Only the second new frog species found in the continental United States in the past 30 years, it remained hidden in plain sight in a city of 8.4 million people.

"It's a pretty unique event," said Rutgers University ecologist Jeremy Feinberg, part of a group of researchers who made the discovery.

As the title of that journal suggests, however, they focused their initial work narrowly on the genetic uniqueness of the then-unnamed frog, which until then was considered a southern leopard frog.

Now, in a study published