guardian.co.uk,
Associated Press, Thursday 12 January 2012
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| The tiny frog called Paedophryne amanuensis measures around 7mm. Photograph: Christopher Austin/LSU/AFP/Getty Images |
Researchers
have discovered in Papua New Guinea what they claim is the world's smallest
frog.
An article Wednesday in the journal PLoS One named Paedophryne amauensis as the world's
smallest animal with a spine.
The adult
frogs are about three-tenths of an inch long, and a millimetre or so smaller
than a carp found on the Indonesian island of Sumatra. The frogs are so small
that Louisiana State University herpetologist and environmental biologist
Christopher Austin had to enlarge close-up photos to describe them.
Austin
discovered the tiny frogs – along with another small frog species – in August
2009 while on a trip to Papua New Guinea to study the extreme diversity of the
island's wildlife.
Steven J.
Beaupre, a University of Arkansas scientist and president-elect of the American
Society of Ichthyologists and Herpetologists, said many vertebrates have males
and females of very different sizes, "so it is reasonable that the world's
smallest vertebrate may end up being either the males or the females of some
specific fish or amphibian species."
He said he
doesn't pay attention to "tiniest" reports, but the frogs themselves
are a significant discovery.
"The
discovery of two new frog species comes as great news against the background of
more prevalent accounts of tropical amphibian extinction," he wrote in an
email.
Knowing
about such tiny creatures and their ecology, he said, helps scientists
"better understand the advantages and disadvantages of extreme small size
and how such extremes evolve. Fundamentally, these tiny vertebrates provide a
window on the principles that constrain animal design."
Austin said
that since these frogs hatch out as hoppers rather than tadpoles and live on
the ground, their existence contradicts the hypothesis that evolution at large
and small extremes is linked to life in water.
At least 29
species of minuscule frogs in equatorial regions worldwide live in leaf litter
or moss that is moist year-round and eat even tinier invertebrates, creating a
previously unknown "ecological guild" of similar animals with similar
life habits, he said.
"We
realised these frogs were probably doing something incredibly different from
what normal frogs do – invading this open niche of wet leaf litter that is full
of really tiny insects that other frogs and possibly other creatures weren't
eating," Austin said.
In August
2009, Austin and graduate student Eric Rittmeyer were collecting and recording
the mating calls of frogs at night in a tropical forest near the village of
Amau in eastern Papua New Guinea, when they heard a chorus of high-pitched
"tinks."
"This
frog has a call that doesn't sound like a frog at all. It sounds like an
insect," he said.Austin estimated that they found 20 previously unknown
species in New Guinea, which is such a hotspot of diversity that scientists
figure they've described only about six-tenths of all the species living there.
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