New species

Scientists discover new species all the time - on the order of 15,000 a year. One of the latest additions to the tree of life is a new type of leopard frog. Which might sound unremarkable, except for where it was found: New York City.But how does a frog go [unnoticed:undetermined] in the Big Apple? Well, even experts have a hard time telling this new species from its [northern:eastern] and southern cousins on looks alone. But the new guy has a [different:separate] croak, which raised ecologists' suspicions. So they tracked down four leopard frog populations with the unique call - including one within view of the Statue of Liberty - and took DNA samples.As they suspected, the odd croakers weren't southern or northern leopard frogs, or even a mix. They had a [genetic:genes] ancestry of their own - earning them new species status. Those results appear in the journal Molecular Phylogenetics and Evolution.The frogs are tough New Yorkers - the center of their range appears to be Yankee Stadium. But the researchers say that the urban amphibians face threats like [pesticides:fertilisers] and infectious diseases. Not to mention real-life games of Frogger.