A famous training to produce T. rex now, fossils have given the earliest evidence of primates from the fossil record, in which a significant discovery is being hailed.
According to a new report, jaw bones and an assortment of teeth found in the Hell’s Creek Formation in northeastern Montana are the oldest primate fossils ever discovered. research published in the Royal Society Open Science.
These animals, which date back to about 65.9 million years ago, lived between 105,000 and 139,000 years after the extinction of the Cretaceous-Paleogene, in which an asteroid wiped out most plant and animal species. the earth. The new paper was co-directed by Gregory Wilson Mantilla of the University of Washington and Stephen Chester of Brooklyn College and City University of New York.
“This is an important study because it documents the oldest primates ever discovered, tracing the date of the oldest primates to the oldest Paleocene, as well as establishing greater diversity,” said Eric Sargis, a professor of anthropology at the University of Yale, which is not affiliated with the new studio, said in an email.
In fact, the age of these fossils is significant, as it suggests that the ancestor of all primates, both extinct and existing, lived during the Mesozoic, specifically the Late Cretaceous. Prior to this discovery, the earliest evidence of primates from the stem or early fossils of the fossil record dates back to the early 300,000 to 500,000 years of the Paleocene (the period following the Mesozoic).
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The newly discovered teeth and jaws belong to two different species: P. janisae i P. mckeeveri. Both species belong Purgatorius, the oldest known genus associated with primates. Other members of this group are P. unio i P. ceratops, and all are considered plesiadapiformes, a group of primates that includes Purgatorius and from where all modern primates such as monkeys, apes (included) and lemurs descend.
P. janisae it was already known to paleontologists, however P. mckeeveri is a recently described species named in honor of a family that has supported fieldwork in this area. Three teeth with features not seen before in Purgatorius allowed scientists to declare the discovery of a new species.
The team studied these extinct creatures by examining a large collection of fossils at the University of California’s Museum of Paleontology, which houses the largest collection of P. janisae fossils. They also had other epoxy molds Purgatorius fossils to work with, as well as expanded 3D models printed from microCT scans. The team also used a technique called “geometric morphometry” to digitize and compare the characteristics of fossils with other known species.
“This work was done with a great team that contributed different and critical skill sets to this research, from geochronologists who were able to fix the age of these fossils to geologists who were able to decipher how these fossils were deposited, “Mantilla said. in an email. “We would not have been able to do this job without the help of generous colleagues from the museums we worked for. [with] and landowners in Garfield County, Montana, who allowed us to work on their land. It was a great team effort. “
Scientists still do not know the exact time for the appearance of Purgatorius, but the “fact that there are two species” that appeared so shortly after the mass extinction “implies that their ancestor was larger than the two descending species,” Mantilla wrote. It was increasingly likely that the ancestor of the Plesiadapiformes “first emerged in the late Cretaceous rather than the Paleocene,” he said, meaning the first primary primates would have rubbed their elbows with the dinosaurs.
As for the precursor of Purgatorius, this is still a mystery. As Mantilla explained, it has been proposed that some American fossil species dating back to the late Cretaceous were ancestral. Purgatorius, including the rat-like one Gypsonictops. It’s probably more likely that “we haven’t found the ancestor in the fossil record yet,” he added.
These tiny placental mammals looked very similar to the squirrel, however Purgatorius, like other plesiadapiformes, “share dental traits with other primates,” Sargis said, adding that their teeth were “primate-like, not rodent-like.”
I asked Chester what makes a primate a primate, to which he replied:
This is a big question and a central topic for all researchers studying the origins of primates. Until we fully understand what makes a primate a primate, it’s hard to know when our primate ancestors separated from other mammals. Today, many primates have traits associated with uptake, jumping, a plant-based diet, improved vision, and intelligence. However, we know from the fossil record that all of these traits did not evolve at the same time. As paleontologists, we can trace this combination of traits to extinct primates from the earliest Eocene about 56 million years ago. But as we go further back in time to the oldest Paleocene about 66 million years ago, it is clear that our first primate relatives like Purgatorius had some, but not all, of these traits. Two important feature suites that evolved very early in the evolution of primates were skeletal features such as holding hands and feet for life in trees and dental features such as specialized molars for eating non-leafy plant products such as fruit. This combination of traits allowed our first primate relatives to break away from their competition right after the dinosaurs disappeared.
As shows the new study, Purgatorius they were among the first mammals to succeed in the Paleocene, which appears “shortly after the catastrophe that wiped out non-avian dinosaurs,” Mantilla explained. “They had a couple of adaptations that allowed them to thrive in the wake of this disaster. First, they were arboreal (they spent most of their time in the trees) and, second, they had teeth that allowed them to feed on fruit and insects. “
It seems that these traits were allowed Purgatorius “to grow and become an important part of the terrestrial ecosystem in a million years after mass extinction,” he added.
Mammals first appeared during the Late Triassic, about 300 million years ago (we’ve been around for a long time!). That primates could thrive after the extinction of non-avian dinosaurs is no huge surprise. Indeed, the mammals quickly took over once the terrible lizards disappeared, giving rise to the Age of Mammals approximately 10 million years after the extinction of the Cretaceous-Paleogene.
After living in the shadows of dinosaurs for hundreds of thousands of years, our time had finally arrived.