Smithsonian researchers have linked discoveries within Arizona’s Petrified Forest National Park with a previously unknown transitional period between old and new continental vertebrates.
For the first time, scientists are able to prove that communities of land vertebrates from the older archaic reptiles to the more familiar like turtles were actually living together before a great extinction event at the end of the Triassic period.
“The big importance of this fossil site is that it fills a global gap in our understanding of what continental ecosystems looked [like] at this time frame," said Ben T. Kligman, the lead author of the study.
He says the Triassic period ended with the breakup of supercontinent Pangaea, which made it difficult to pinpoint evidence of when modern land vertebrates first began.
Gavin McCullough, with the Arizona Museum of Natural History, says at the time, Arizona was not in the same geographical place on Earth. Before Pangaea broke up, Arizona was more down by the equator.
"The last 12 or so million years of the Triassic, before the extinction — that led to the Jurassic period afterwards — is kind of shrouded in mystery and there's not a lot of places where they're able to find reliably datable fossils from that time period," McCullough said.
He is unaffiliated with the discovery but says it's an exciting find.
Kligman says the fossil highlights one of the world’s oldest turtle fossils and the jaw bone of a new species of Pterosaur, a small flying reptile. That Pterosaur was also determined to be the oldest in North America.
"So these are these groups that would go on and dominate continental ecosystems after the Triassic period," Kligman said.
This overall project has been nearly two decades in the making since unearthing ancient fossils and rock in Arizona.
-
A new clinical trial wants participants who have been diagnosed with mild to moderate Alzheimer’s disease and screen positive for the bacteria that causes gingivitis. -
Valley residents will feel a brief cooldown this week. The National Weather Service predicts high temperatures in the high 80s to lower 90s in the early weekdays. But it's temporary solace as the summer season approaches. -
Older adults are having sex, and they’re not always using protection. Context is important here: Protection to one generation might mean from pregnancy. They might not consider STIs. And stigma remains a barrier. -
The risk of human-caused wildfire is high due to hot and dry conditions. Certain activities are now restricted within state trust lands in Gila, Maricopa and Pinal counties, as well as the Tonto National Forest. -
Overdose deaths fell in the vast majority of states, although seven saw at least slight increases, including jumps of 10% or more in Arizona, Colorado and New Mexico, the preliminary data from the Centers for Disease Control and Prevention showed.
