The tropical forest of Papua New Guinea is home to the smallest animal with a backbone, a frog dubbed Paedophryne amanuensis.
Christopher Austin, LSU
The tropical forest in Papua New Guinea is a noisy place at night, filled with the calls from all sorts of living things: frogs, birds and insects, including especially loud cicadas. One particular call — a high-pitched, cricketlike "tink-tink-tink" — caught the attention of herpetologist Christopher Austin and his graduate student Eric Rittmeyer.
Together, they tried to locate the noisemaker, which they assumed was an insect. Four times, they attempted to hone in on the source of the calls, but each time they failed to find the creature in leaf litter on the forest floor. On the fifth try, they grabbed the dead leaves and dropped them in a clear plastic bag. Then, back at camp, they went through and began checking each of the hundreds of leaves they had picked up.
A tiny animal hopped off one of the leaves. This miniature frog, now dubbed Paedophryne amanuensis, has taken over the title of smallest vertebrate, an animal with a backbone. Though they discovered the frog in 2009, only now have they described their finding in a scientific journal. [40 Freaky Frog Photos]
The previous record holder was an acidic swamp-dwelling fish from Indonesia called Paedocypris progenetica. But with an average length of 0.3 inches (7.7 millimeters) from nose to butt, the tiny frog now holds the title. It is so small, that end to end, more than two would fit on a dime.