The reptiles first appeared during the Triassic period and became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event some 200 million years ago. Dinosaurs and their flying partners pterosaurs both belong to the group Ornithodira, but their origins and relationships are poorly understood as few specimens near the root of this lineage have been found. But the discovery of a newly described relative found in Madagascar could change all that.
The specimen, named Kongonaphon kely, or “tiny bug slayer”, stood at just 10cm tall and is believed to date back 237 years, a study published in the Proceedings of the National Academy of Sciences revealed.
Featured in the BBC’s Science Focus Magazine this month, Christian Kammerer, from the North Carolina Museum of Natural Sciences, said: “There’s a general perception of dinosaurs as being giants.
“But this new animal is very close to the divergence of dinosaurs and pterosaurs, and it’s shockingly small.”
Kongonaphon is not the first small fossil animal known near the root of the ornithodira family tree but, previously, such specimens were considered isolated exceptions.
In general, scientists thought body size remained similar among the first larger reptile group – known as archosaurs – that includes birds, crocodilians, non-avian dinosaurs, and pterosaurs.
They are then thought to have increased to gigantic proportions in the dinosaur lineage.
Dr Kammerer added: ”Analysing changes in body size throughout archosaur evolution, we found compelling evidence that it decreased sharply early in the history of the dinosaur-pterosaur lineage.”
The scientists also discovered evidence, through wear on its teeth, that the Kongonaphon ate insects.
A shift to this kind of diet, which is associated with small body size, may have helped early ornithodirans survive by occupying a niche different from their mostly meat-eating contemporaneous relatives.
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Through the first half of the 20th century, before birds were recognised to be dinosaurs, most of the scientific community believed dinosaurs to have been sluggish and cold-blooded.
Research conducted since the Seventies, however, has indicated that all dinosaurs were active animals with elevated metabolisms and numerous adaptations for social interaction.
Some were herbivorous, others carnivorous.
Evidence suggests that all dinosaurs were egg-laying and that nest-building was a trait shared by many.
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