Ribbiting news: frogs’ poison spines revealed and new species discovered
In two separate breakthroughs, a new species of tree frog has been discovered, while two species of Amazonian frog have been revealed to be venomous
Many of world’s frogs may be at risk of extinction, but something new always hops up in the amphibian world. In two separate journals in one afternoon, scientists have identified a brand new tree frog species high in the Peruvian cloud forest, while on the other side of the Andes, a biologist in the Amazon basin discovered the hard way the secret of survival of two familiar species: they are venomous.
The deadly duo – formally named Corythomantis greeningi and Aparasphenodon brunoi – are not just poisonous in the way made notorious by the poison dart frogs known as Dendrobatidae, which are the ones that indigenous Amerindians traditionally used to poison their blow darts. They are poisonous in the sense that they can inject a toxin from a sharp spine on their heads.
The poison is more deadly than the secretions of a pit viper, and one of the discoverers, Carlos Jared of the Instituto Butantan in Sao Paulo found out the hard way. While collecting C. greeningi he got a spine in his hand: intense, radiating pain followed for the next five hours.
The experience immediately explained why no hungry hunters are known to dine off either kind of frog. “This action would be even more effective on the mouth lining of an attacking predator,” said Dr Jared. As he and his research colleague Edmund Brodie of Utah State University tell the story in the journal Current Biology, it may have been a lucky strike. They calculate that one gram of toxin from the other, even more poisonous species, would be enough to kill 300,000 mice, or about 80 humans.
“It is unlikely that a frog of this species produces this much toxin, and only very small amounts would be transferred by the spines into a wound,” said Brodie. “Regardless, we have been unwilling to test this by allowing a frog to jab us with its spines.”
Meanwhile, 2350 metres high in the forests of the Peruvian Andes, biologists found a tiny fleshbelly frog hardly bigger than a beetle and hitherto unknown to science that had been leaping around in the leaf litter under their feet. The frog has been named Noblella madreselva (which means “mother jungle” in Spanish), in the journal Zookeys by its discoverers Allessandro Catenazzi of Southern Illinois University and Dr Vanessa Uscapi.
It announced itself by its striking colouration: a wide white mark on a black background, stretching from chest to belly, with a brown splash on its head that looks like a dark facial mask. The frog may have escaped notice until now, but it may survive only in that location, and in parts of the forest not yet logged. So it could be at high risk of hopping away to extinction. Half of all the world’s toads, frogs, newts and salamanders are in decline, and one third are at risk of extinction.
“It is therefore imperative to document the highly endemic amphibian faunas of the wet montane Andean forests as a first step towards designing a network of natural reserves that maximises protection of amphibian diversity,” the authors say.