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If you think about mammoths, some species extinct barely 3,000 years ago, their existence is nothing but a breath. Today's elephants have echoes of their lives that cross our world in a way that may not be so different from that of their former parents. Mammoths are almost tangible in this way.
Few people know the behemoths, the larger ones and, in some cases, the cousins of the mammoths living in the forest. Like some species of mammoths, the American mastodon (Mammut americanum) lived throughout North America during the Pleistocene. Their extinction took place 10,000 to 12,000 years ago.
The predominant species, discovered and studied from coast to coast for over 200 years, has been American Mammut.
Until today.
In a new article published in PeerJ, Alton Dooley, Jr. and his colleagues announce the discovery of Mammut pacificus, a new species of mastodon specific to a small segment of western North America. This is the first new species of North American mastodon to be recognized in 50 years.
None of the six authors expected this result from their research. In fact, they explored all the other avenues except define a new species in the years preceding this article.
"I had the impression of beating tooth and nail against a new species," said Dooley, Jr. "and whenever I tried to beat myself, the data would Did not stop hitting me!
"One of the reasons we did not expect this is [because] it is a megafauna animal of the Pleistocene. The Pleistocene is so well studied. That's not to say that we understand everything about it, but not so long ago, [and therefore] there are huge Pleistocene collections around the world, "said Dooley, executive director of the Western Science Center. "I'm shocked that a mastodon taxon has not been recognized for so long."
Adding to the surprise, none of the fossils studied in this research have been excavated recently. Many were carefully collected in what is now known as Diamond Valley Lake and were eventually stocked at the Western Science Center in Hemet, California. A team of diggers led by co-author Kathleen Springer worked to search as many fossils as possible in the 1990s. They discovered 100,000 Pleistocene fossils. Everything else stays under billions of gallons of water – an emergency water tank for southern California.
It is however important to note that 100 individual behemoths were found in this dig, known as Diamond Valley Lake assembly. This is the largest number of southwestern behemoths not in a pit of tar, and this certainly added to the data set. [Full disclosure: I contributed to a crowdfunding campaign that supported the initial research of this study three years ago.]
With narrower molars than their American mastodon cousins, more vertebrae in the pelvis, a lack of defense in the lower jaw and a slightly different femur, these differences may indicate one of the reasons why this species has remained hidden at view.
"Naming a new species, especially in the fossil record, can be as much of a" decision "as a" discovery "," said Adrian Lister, proboscid expert at the Natural History Museum. London. "Unless the new species is clearly unique, it will have one or more close relatives, as is the case here, so that the question becomes: should these be regarded as separate species or only subspecies or some other kind of variety? Even for living species, for which we have much more information … there is often disagreement among taxonomists about what constitutes a species. "
"In the case of the mastodons, I think the authors have a reasonable basis for erecting a new species. The differences are not major …[b]The differences are consistent and, importantly, the authors show that this difference has a clear geographic basis (California and possibly adjacent states) and also persisted for about two million years of the Pleistocene, "he said. Lister writes. "This shows a well-rooted geographical and presumably genetic difference that makes the erection of a new species defensible."
Eric Scott, co-author of the new study and paleontologist who worked with Kathleen Springer to excavate the Diamond Valley Lake assemblage, often met with Dooley, Jr. to discuss the meaning of fossil data.
"There was a concrete difference in these animals that was consistent in a geographic area," Scott said. "And that was the most important part for me, it was consistent for a prolonged period of geological time. I had the same problem with [fossil] horses. If the anatomical configuration of a horse differs from one region to another, and this anatomy lasts for tens of thousands of years, it means that there is no exchange of genetic information with any of these other horses, which is reproductive. isolation, which is the biological definition of a species. [We were] see the same thing with these behemoths. "
Kathleen Springer, the main force behind the digs at Diamond Valley Lake and now a geologist at the US Geological Survey, is justifiably excited.
"[T]This is a dramatic result from the point of view of vertebrate paleontology and the scientific process, "she wrote in an email. "[It is also] testimony to the necessity and usefulness of natural history museums. "
His work at the new USGS radiocarbon laboratory provided a new radiocarbon dating for many of the mastodons studied in this research, using "material that had never been tried before (eggshell, etc.). ). " Succinidés shells of gastropods and plant fibers). "
What does this research mean for the average person and why should we care? In addition to increasing our knowledge of the Pleistocene megafauna, this increases our understanding of life on this planet. We need to take a step further to know how this life has evolved, existed and finally disappeared. And this certainly encourages even more questions that call for answers: Why, for example, did this particular species evolve with these particular anatomical features? What does it say about the environment in which he lived?
Brett Dooley, another co-author of the paper and educator at the Western Science Center, expressed hope that publishing the research in an open-access journal will encourage more people to read information about the new juggernaut.
"I am [also] hoping the people of the Hemet area will be proud of it, [naming a new species] is not something that happens every day I hope that they can understand this and derive a sense of ownership themselves. "
Jeanne Timmons (@mostlymammoths) is a freelance writer based in New Hampshire who writes blogs on paleontology and archeology at mostmammoths.wordpress.com.
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