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In the collective imaginary, the dinosaurs are creatures mighty and thundering as the Tiranosuario rex. But new research suggests that the ancestors of these majestic animals and their relatives pterosaur -a huge flying reptiles-not impressed him precisely because of his size.

A team of scientists has discovered the tiny Kongonaphon kely , or “little killer insects”, who lived about 237 million years ago in Madagascar. This reptile, which would have measured approximately a mere 10 centimeters in height, is near the root of the lineage Ornithodira they belong to both dinosaurs such as the pterosaurs. Almost would have fit in a human hand.

Illustration of the reptile from Madagascar is shown to scale with human hands – Frank Ippolito, © American Museum of History NaturalFósiles amazing

“There is a general perception that dinosaurs are giant”, says Christian Kammerer, of the Museum of Natural Sciences North Carolina (US). “But this new animal is very close to the divergence of dinosaurs and pterosaurs, and it is surprisingly small”.

The fossil of Kongonaphon were discovered in 1998 by a team of researchers led by the curator of mammalian fossils Frickil John Flynn, who worked at the Field Museum at that time, in close collaboration with scientists and students of the University of Antananarivo (Madagascar) and the California-Santa Barbara.

“This site fossil in the south-west of Madagascar of an interval of time little known throughout the world has produced some fossils surprising, and this small specimen was mixed among the hundreds that we have collected from the site over the years,” explains Flynn. “It took some time before we could focus on these bones, but once we did, it was clear that we had something unique and worthwhile to look more closely. This is a great case for why the findings of the field, combined with modern technology to analyze fossils recovered, they remain as important,” he stresses.

Although we have found a few specimens near the root of this lineage, Kongonaphon is not the first small animal known that can be placed there. Previously, such specimens were considered to be “isolated exceptions to the rule,” says Kammerer.

Comparison of body size between the newly discovered Kongonaphon kely (left) and one of the earliest dinosaurs, Herrerasaurus – Silhouettes phylopic.org by Scott Hartman (CC BY 3.0) and AMNH / Frank Ippolito

In general, the scientific thinking was that the size of the body remained similar between the first archosaurs, the largest group of reptiles that includes birds, crocodiles, dinosaurs, non-avian and pterosaur, including the first Ornithodoros, before increasing to gigantic proportions in the lineage of the dinosaurs.

Minituarización

To analyze changes in body size along the evolution of the archosaurs, the researchers found evidence that fell sharply early in the history of the lineage of dinosaur-pterosaur. This event of “miniaturization” has important implications.

For example, the use of the teeth of Kongonaphon suggests that it ate insects. This diet is associated with a small body size, so that a change to a diet of insects may have helped the Ornithodoros early to survive and occupy a niche different from its contemporary relatives in your most carnivorous.

The scientists excavate fossils at sunset in the southwest of Madagascar. Kongonaphon kely was discovered in this site – J. Flynn

The work, published in the journal “PNAS”, also suggests that the linings of the skin ranging from simple filaments to feathers, known both in dinosaurs and in pterosaurs, may have originated in this common ancestor of the small body to help regulate body temperature. This is due to the retention of heat in small bodies is difficult, and the Triassic to late it was a time of climatic extremes.

“The discovery of this small relative of dinosaurs and pterosaurs emphasizes the importance of the fossil record of Madagascar to improve the knowledge of the history of vertebrates in times that are little known in other places,” says the co-director of the project Lovasoa Ranivoharimanana, of the University of Antananarivo.