Thursday, 4 March 2021

Evolution News - Our Ancestors Walked (or Probably Crawled) With Dinosaurs

Artists impression of the newly discovered early primate species, Purgatorius mckeeveri.
Illustration by Andrey Atuchin
New Fossil Discovery Illuminates the Lives of the Earliest Primates

No matter what forgeries and inventions Creation frauds resort to to fool their dupes into believing humans lived amongst dinosaurs, we know they died out some 63, million years before even archaic pro-hominins were around. They were killed in the sudden Cretaceous-Paleogene mass extinction event 66 million years ago.

However, dinosaurs did live alongside the earliest ancestors of the primates, according to the discovery by a team from the City University of New York (CUNY) Graduate Centre. This claim is based on an examination of fossil teeth found in the Hell Creek area of north-eastern Montana which have been dated to 65.9 million years old, in other words, to between 105,000 and 139,000 years after the dinosaurs vanished.

The extinction of the dinosaurs freed up lots of ecological niches that the early ancestors of the mammals were able to radiate into, giving rise to most of the stem species of modern mammalian families, including the primates.

The CUNY New release explains:
A Graduate Center, CUNY/Brooklyn College professor was part of a discovery of the first fossil evidence of any primate, illustrating the earliest steps of primates 66 million years ago following the mass extinction that wiped out all dinosaurs and led to the rise of mammals.

Stephen Chester, an assistant professor of anthropology and paleontologist at the Graduate Center, CUNY and Brooklyn College, was part of a team of 10 researchers from across the United States who analyzed several fossils of Purgatorius, the oldest genus in a group of the earliest-known primates called plesiadapiforms. These ancient mammals were small-bodied and ate specialized diets of insects and fruits that varied across species.

This discovery is exciting because it represents the oldest dated occurrence of archaic primates in the fossil record. It adds to our understanding of how the earliest primates separated themselves from their competitors following the demise of the dinosaurs.

Stephen Chester
Assistant professor of anthropology and paleontologist
Graduate Center, CUNY and Brooklyn College, New York
This discovery is central to primate ancestry and adds to our understanding of how life on land recovered after the Cretaceous–Paleogene extinction event 66 million years ago that wiped out all dinosaurs, except for birds. This study was documented in a paper published in the journal Royal Society Open Science.

“This discovery is exciting because it represents the oldest dated occurrence of archaic primates in the fossil record,” Chester said. “It adds to our understanding of how the earliest primates separated themselves from their competitors following the demise of the dinosaurs.”

Abstract


Plesiadapiform mammals, as stem primates, are key to understanding the evolutionary and ecological origins of Pan-Primates and Euarchonta. The Purgatoriidae, as the geologically oldest and most primitive known plesiadapiforms and one of the oldest known placental groups, are also central to the evolutionary radiation of placentals and the Cretaceous-Palaeogene biotic recovery on land. Here, we report new dental fossils of Purgatorius from early Palaeocene (early Puercan) age deposits in northeastern Montana that represent the earliest dated occurrences of plesiadapiforms. We constrain the age of these earliest purgatoriids to magnetochron C29R and most likely to within 105–139 thousand years post-K/Pg boundary. Given the occurrence of at least two species, Purgatorius janisae and a new species, at the locality, we provide the strongest support to date that purgatoriids and, by extension, Pan-Primates, Euarchonta and Placentalia probably originated by the Late Cretaceous. Within 1 million years of their arrival in northeastern Montana, plesiadapiforms outstripped archaic ungulates in numerical abundance and dominated the arboreal omnivore–frugivore niche in mammalian local faunas.

Wilson Mantilla, Gregory P.; Chester, Stephen G. B.; Clemens, William A.; Moore, Jason R.; Sprain, Courtney J.; Hovatter, Brody T.; Mitchell, William S.; Mans, Wade W.; Mundil, Roland; Renne, Paul R.
Earliest Palaeocene purgatoriids and the initial radiation of stem primates
Royal Society Open Science
(8) 2: 210050 doi:10.1098/rsos.210050

Copyright: © 2021 The authors. Published by the Royal Society
Open access
Reprinted under a Creative Commons Attribution 4.0 International License (CC BY 4.0)
Chester and Gregory Wilson Mantilla, Burke Museum Curator of Vertebrate Paleontology and University of Washington biology professor, were co-leads on this study, where the team analyzed fossilized teeth found in the Hell Creek area of northeastern Montana. The fossils, now part of the collections at the University of California Museum of Paleontology, Berkeley, are estimated to be 65.9 million years old, about 105,000 to 139,000 years after the mass extinction event.

Based on the age of the fossils, the team estimates that the ancestor of all primates (the group including plesiadapiforms and today’s primates such as lemurs, monkeys, and apes) likely emerged by the Late Cretaceous—and lived alongside large dinosaurs.

“Stephen Chester’s high-caliber impactful research in this area with Brooklyn College students has significantly contributed to our understanding of the environmental, biological, and social dependencies that ultimately led to the evolution of primates," said Peter Tolias, dean of the School of Natural and Behavioral Sciences.
The rapid radiation of these early mammals illustrates how a major change in their environment can cause species to diverge into newly-vacated niches and produce new species over a very short period - in this case just over a hundred thousand years. It also shows how close our earliest primate ancestors were to the generalised stem mammals that had arisen alongside dinosaurs from the warm-blooded, hairy mammaliaform reptiles.








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