Kongonaphon kely: Tiny Dinosaur Relative Roamed Triassic Madagascar
A new genus and species of ornithodiran — an early relative of dinosaurs and pterosaurs — that lived around 237 million years ago (Triassic period) has been identified from the fossilized remains found in southwestern Madagascar. Named Kongonaphon kely, the ancient reptile was surprisingly small (estimated height – 10 cm, or 3.9 inches). Its tiny body size may help explain the origins of flight in pterosaurs and the presence of ‘fuzz’ on the skin of both pterosaurs and dinosaurs.
“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,” said Dr. Christian Kammerer, a research curator in paleontology at the North Carolina Museum of Natural Sciences.
“Discovery of this tiny relative of dinosaurs and pterosaurs emphasizes the importance of Madagascar’s fossil record for improving knowledge of vertebrate history during times that are poorly known in other places,” added University of Antananarivo’s Professor Lovasoa Ranivoharimanana.
The partial skeleton of Kongonaphon kely was found in 1998 in the Morondava Basin of southwestern Madagascar.
“Kongonaphon kely isn’t the first small animal known near the root of the ornithodiran family tree, but previously, such specimens were considered isolated exceptions to the rule,” Dr. Kammerer said.
“In general, the scientific thought was that body size remained similar among the first archosaurs — the larger reptile group that includes birds, crocodilians, non-avian dinosaurs, and pterosaurs — and the earliest ornithodirans, before increasing to gigantic proportions in the dinosaur lineage.”
“Recent discoveries like Kongonaphon kely have given us a much better understanding of the early evolution of ornithodirans. Analyzing changes in body size throughout archosaur evolution, we found compelling evidence that it decreased sharply early in the history of the dinosaur-pterosaur lineage.”
“This miniaturization event indicates that the dinosaur and pterosaur lineages originated from extremely small ancestors yielding important implications for their paleobiology.”
Pitted microwear on Kongonaphon kely’s conical teeth indicates a diet of hard-shelled insects.
This shift to insectivory, which is associated with diminutive body size, may have helped early ornithodirans survive by occupying a niche different from their mostly meat-eating contemporaneous relatives.
The study also suggests that fuzzy skin coverings ranging from simple filaments to feathers, known on both the dinosaur and pterosaur sides of the ornithodiran tree, may have originated for thermoregulation in this small-bodied common ancestor.
That’s because heat retention in small bodies is difficult, and the mid-late Triassic was a time of climatic extremes, inferred to have sharp shifts in temperature between hot days and cold nights.
The discovery is reported in a paper in the Proceedings of the National Academy of Sciences.
Christian F. Kammerer et al. A tiny ornithodiran archosaur from the Triassic of Madagascar and the role of miniaturization in dinosaur and pterosaur ancestry. PNAS, published online July 6, 2020; doi: 10.1073/pnas.1916631117