His jaw, discovered in 1882, is the subject of numerous studies and is the only one to show teeth in the lower part. It is the Gastrotheca guentheri.
There is only one species of frog with teeth. It is the Gastrotheca guentheri that, among the more than seven thousand types currently known, would be the only one to have teeth in the lower jaw. The discovery has been made by the scientists of the University of Florida who have examined a find, found in 1882 and since then object of numerous studies. The analysis has been published in the journal Evolution, to carry it out was a team led by Daniel Paluh. The researchers, using high-resolution techniques, have traced specific compounds and tissues within the presumed teeth.
The discovery of the frog with teeth
"The teeth are made of dentin and enamel - explained Daniel Paluh - but these structures, the size of a grain of sand, are really difficult to examine in guentheri. Since first appearing in fossil records dating back more than 200 million years, frogs have become known for their lack of teeth. Instead, the University of Florida research team determined that frogs may have lost their teeth on at least 20 separate occasions, regaining them on six episodes throughout their evolutionary history.
Frogs may be an exception in nature
The researchers' suggested thesis, however, contradicts the law that a given lost trait in a species does not reappear. The scholars suggest that frogs may be a significant exception to this principle. Gastrotheca guentheri are native to the rainforests of Colombia and Ecuador, but may have disappeared after 1996. The last sighting was just 25 years ago.
The study looked at a guentheri embryo preserved in museum collections. "These frogs do not lay their eggs in ponds or streams," Paluh said, "but are equipped with a pouch on their backs from which the eggs hatch without the intermediate tadpole stage. The scientists then performed scans of the embryo's jaws, discovering actual teeth. The research team now plans to exploit genetic tools to map the evolution of the frogs' teeth.
"DNA tends to degrade over time," Paluh concluded, "and animals preserved in museum collections may not be sufficient to undertake the genetic study. We don't know if this species is completely extinct, but we do know the environmental dangers many frogs face due to climate change, habitat degradation and a range of diseases."
Still on the subject of amphibians, other scholars are making beauty products from the foam of a particular species of frog, while through tadpoles a being that doesn't need to breathe has been created in the lab.
Stefania Bernardini