Long-limbed and sporting dramatic horns above its eyes, Guenther’s marsupial frog is a bizarre-looking amphibian from the misty cloud forests of the Andean slopes. Like other marsupial frogs this species, known as Gastrotheca guentheri, doesn’t produce free-swimming tadpoles, but rather rears its young under a flap of skin on its back.

But it has one even more puzzling trait: It possesses a full set of teeth.

Wait. Frogs have teeth? Actually, yes: Most frogs have a small number of them on their upper jaws. But virtually all 7,000 species of living frogs lack teeth along their lower jaws—except for G. guentheri.

Unfortunately, this species hasn’t been sighted since 1996—and even before then, was seldomly found or studied. There are precious few samples of