Ancestors of the Dinosaurs and Pterosaurs May Have Been Rather Small

[Recusant]

. . . and perhaps fuzzy, too. 

"A tiny ancient relative of dinosaurs and pterosaurs discovered" | ScienceDaily

Dinosaurs and flying pterosaurs may be known for their remarkable size, but a newly described species from Madagascar that lived around 237 million years ago suggests that they originated from extremely small ancestors. The fossil reptile, named Kongonaphon kely, or "tiny bug slayer," would have stood just 10 centimeters (or about 4 inches) tall. The description and analysis of this fossil and its relatives, published today in the journal Proceedings of the National Academy of Sciences, may help explain the origins of flight in pterosaurs, the presence of "fuzz" on the skin of both pterosaurs and dinosaurs, and other questions about these charismatic animals.

"There's a general perception of dinosaurs as being giants," said Christian Kammerer, a research curator in paleontology at the North Carolina Museum of Natural Sciences and a former Gerstner Scholar at the American Museum of Natural History. "But this new animal is very close to the divergence of dinosaurs and pterosaurs, and it's shockingly small."

[. . .]

"Kongonaphon 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," Kammerer noted. 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 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," Kammerer said.

This "miniaturization" event indicates that the dinosaur and pterosaur lineages originated from extremely small ancestors yielding important implications for their paleobiology. For instance, wear on the teeth of Kongonaphon suggests it ate insects. A shift to insectivory, 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.

The work 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.

[Continues . . .]

[Tank]

I wish I had a time machine. 

[Sandra Craft]

I wish I had a time machine. 

I know, so frustrating!