Scientists searching for “lost amphibians” have discovered the Old World’s smallest frog, living in carnivorous pitcher plants in the jungles of Borneo.
As in the Dr. Seuss fable Horton Hears a Who, the pea-sized creatures were detected only because of the sound they made.
According to Malaysian herpetologist Indaeil Das, who discovered the frog with his colleague Alexander Haas of Germany, it was the wee beasties’ “harsh rasping notes” at dusk that drew their attention.
“We heard the calls of this frog and we knew the calls of all frogs in the area and this was different,” Das told AFP. “At first we couldn’t see it, but eventually we found it. I had to trap the frog in one of my baby son’s clean white diapers in order to really see what it looked like, it was so tiny.”
“You often get tiny frogs making quite a noise,” confirmed herpetologist Robin Moore, who is leading expeditions worldwide bent on rediscovering a hundred species of “lost amphibians” declared extinct. Das will join Moore in Indonesia in September, to search for the Sambas stream toad, last seen in the 1950s.
The frog heard by Haas and Das had not previously been classified; museum specimens collected more than a hundred years ago were misidentified as juveniles of another species.
The frog has been dubbed Microhyla nepenthicola, in honor of the Nepenthes ampullaria species of miniature pitcher plant that it needs to breed.
Although the micro-beast is “definitely the tiniest [frog] in Asia, Africa and Europe,” says Das, it is not as small as this frog, Eleutherodactylus iberia, which lives in Cuba, and as yet has no English common name.
The frog was found alongside a road in Kubah National Park in Malaysia’s Sarawak state on Borneo in 2004, but word didn’t get out until last week, when the taxonomic journal Zootaxa published Haas and Das’ findings. Considering the planet-wide stress to which amphibians are subjected—more than a third of all species are threatened with extinction—it might not be a bad idea to keep quiet about such things.
The frog measures just 3.0 millimetres when it metamorphoses from a tadpole, and grows to a whopping 9.0 to 11.0 millimetres as an adult. It has been slotted in the Microhylid family of frogs, none of which manage to reach 15.0 millimetres. Most Microhylids are Asian tree frogs.
These particular Microhylids hang out in the miniature pitcher plant Nepenthes ampullaria, which has a globular pitcher and grows in damp, shady forests. Pitcher plants are often carnivorous; this particular species eats ants, but it leaves the frogs alone.
At dusk, male frogs typically gather around a pitcher plant and sing a “love song” for females: raspy, minutes-long serenades separated by brief silences. This frog symphony can go on for several hours, Moore reports.
It was the frog’s croak that convinced Haas and Das that they had stumbled upon a new species, and not a band of juveniles: only adult frogs, says Moore, can sing.
Once an earnestly rasping male has convinced a female to get jiggy with him, the female deposits her eggs over the side of a pitcher plant. Tadpoles grow and metamorphize in the still water that collects in the globular pitcher. Once grown, the frogs feed in and around the plant . . . and eventually get the ball rolling all over again. To bulk up for the rasping and the egg-laying, adults con-sume very tiny flies, young insects, or extremely mi-nute adult insects such as mini-ants.
Haas and Das hope the discovery of this Who-like frog will persuade Malaysia to ease up some on inviting into Borneo international ravagers. It is not known yet whether the new species is threatened or endangered, but the rainforests in which it lives are commonly cleared for lumber and palm-oil plantations. As I recently noted here, the Malaysian government is under increasing pressure—to which it is beginning to respond—to leave off permitting transnational corporations to greedily denude the national landscape.
Below is a version of the Dr. Seuss fable Horton Hears A Who, made in the Ukraine in the 1980s. It is not necessary to understand Russian, into which this film was dubbed, to get what’s going on. I really, really like the portrayal of the Whos here. Pretty magical.
(Thanks to my daughter, who emailed me a link to a story on these micro-frogs, and to faithful red reader possum, who linked to another piece on the Who-like creatures in his diary on the Great Pumpkin.)