Wow, possibly Earth’s earliest dinosaur! Did FoxNews snicker as they read the name, betraying their usual puerile contempt for science? <Oops, forgot to disable rant mode…> @bkcunningham I’m no paleontologist but, based articles I’ve read about paleontology, you’d be surprised how much can be inferred from fossil bones & teeth. The original publicatoin (which you link to above) is here.
Here’s a report about this research from the not-always-reliable LiveScience, which sometimes presents press releases as reported news. Anyhow these excerpts explain some of the inferences that can be made from such fragmentary historical evidence…
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They dated the fossils based on the layer of rock in which it was found and the ages for the layers above and below it (over time layers of sediment accumulate on top of remains, making a vertical slice somewhat of a timeline into the past).
They also looked at the ages of rock layers with similar animal remains found across the globe.
As for whether the beast is a dinosaur, several clues say it is. For instance, dinosaurs grew quickly, and a cross-section of the humerus suggests bone tissue was laid down in a haphazard way, a telltale sign of rapid growth.
“We can tell from the bone tissues that Nyasasaurus had a lot of bone cells and blood vessels,” said co-author Sarah Werning of the University of California, Berkeley, who did the bone analysis. “In living animals, we only see this many bone cells and blood vessels in animals that grow quickly, like some mammals or birds,” Werning said in a statement.
The upper arm bone also sported a distinctively enlarged crest that would’ve served as a place of attachment for arm muscles.
“It’s kind of your shoulder muscle or the equivalent in a dinosaur,” Nesbitt told LiveScience, adding that “early dinosaurs are the only group to have this feature.”
Vertebrate paleontologist and geologist Hans-Dieter Sues, who was not involved in the study, agrees with the dating and dinosaur tag placed on the remains. “I first saw the bones in the 1970s when the late Alan Charig (one of the co-authors) showed them to me,” Sues, of the National Museum of Natural History in Washington, D.C., told LiveScience in an email. At that time none of his colleagues would accept that dinosaurs had appeared so early in geological history.”
Sues added that additional, more complete remains are needed to confirm the relationships between Nyasasaurus and other dinosaurs.