The new species, which biologists are calling the Atlantic Coast leopard frog, was hiding in plain sight. Besides its croak, the new species is nearly indistinguishable from several other frog species living in the area. As detailed today in PLoS ONE, the researchers were able to make the identification after comparing the DNA, appearance, and croaking noises of hundreds of frogs.

The authors, led by Jeremy Feinberg of Rutgers University, first announced their suspicions of the new species in 2012, when they reported that familiar-looking frogs with unfamiliar croaks were hopping around the wetlands near Yankee Stadium. Although the coloration of the Atlantic Coast leopard frog is very similar to that of other leopard frogs, its distinctive croak, which sounds like a simple, repeated “chuck,” sets it apart.