While examining dinosaur fossils in Argentina, paleontologists made an unexpected discovery: the oldest tadpole known to date. This discovery, revealed in the journal Nature, could shed light on our understanding of the evolution of frogs and their stages of development.
An exceptional fossil
Fossils play a crucial role in our understanding of the history of life on Earth. They allow us to explore the evolution of species and trace the adaptations that have taken place over millions of years. In the case of frogs, the existence of tadpole fossils is particularly rare, as these young amphibians generally live in aquatic environments where they are more vulnerable to predators and environmental conditions. Most of the fossils we find come from adults, which makes the discovery of Notobatrachus degiustoi all the more significant.
This fossil is exceptionally well preserved and retains soft tissue impressionsincluding the animal’s eyeballs, gills and even nerves. The specimen, old 161 million years approximately, measures approximately sixteen centimeters long with a tail of 7.6 centimeters. This tadpole also exhibits feeding characteristics similar to those of modern tadpoles. It used a filter feeding system to suck up the plankton and algae present in its aquatic environment.
Finally, note that the animal, discovered in the La Matilde formation, in Patagonia, is at an advanced stage of development. Its vertebrae then began to ossify, a characteristic that allowed researchers to identify it and link it to its adult counterpart.
Implications for frog evolution
This tadpole fossil could end a long-standing debate about the evolution of frogs and the development of their life stages. Indeed, some researchers have long argued that early frogs probably did not have a tadpole stage. However, the fossil of Notobatrachus degiustoi suggests that tadpoles have been around as long as adult frogs themselveswhich challenges preconceived ideas about their evolution.
This discovery, however, raises crucial questions about how frogs have adapted over time. The fact that tadpoles of an ancient species possessed similar characteristics to modern tadpoles indicates that this stage of development may have been present since the beginning of frog evolution. This means that tadpoles could play an important role in the evolutionary history of amphibians, just like adult frogs.
The researchers, excited to further explore this fascinating question, hope to secure funding to return to the site of the La Matilde formation. This would allow them to continue their research and possibly discover other tadpole fossils. New findings could enrich our understanding of frog evolution and shed light on the development of amphibians as a whole.
