A reptile the size of a Labrador retriever may be the oldest known dinosaur, dating back 10 to 15 million years earlier than most dinosaurs that were around in the Late Triassic period.
Named Nyasasaurus parringtoni, the creature probably stood upright, and was 7 to 10 feet long with a 5-foot-long tail.
“For 150 years, people have been suggesting that there should be Middle Triassic dinosaurs, but all the evidence is ambiguous,” said study lead author Sterling Nesbitt at the University of Washington in a press release.
“Some scientists used fossilized footprints, but we now know that other animals from that time have a very similar foot.”
The fossilized bones were found in Tanzania in the 1930s, and have some interesting characteristics, such as disorganized tissue in the humerus or upper arm bone.
“We can tell from the bone tissues that Nyasasaurus had a lot of bone cells and blood vessels,” said study co-author Sarah Werning at the University of California-Berkeley in the release.
“In living animals, we only see this many bone cells and blood vessels in animals that grow quickly, like some mammals or birds.”
The humerus also has a large bony feature, called an elongated deltopectoral crest, to which the upper arm muscles attached.
“What’s really neat about this specimen is that it has a lot of history,” Nesbitt said. “Found in the ’30s, first described in the 1950s but never published, then its name pops up but is never validated.”
“Now 80 years later, we’re putting it all together.”
The findings were published online in Biology Letters on Dec. 5.
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