2023-11-27 11:38:02
The very existence ofEkgmowechashala was rather enigmatic. Paleontologists knew that the small, very singular animal weighing around 2 kg and looking like a lemur had been the last monkey to populate the territory corresponding to today’s Great American Plains, but the evolution of the species remained poorly understood. Its place among primates has even been debated.
Due to its unique morphology and the fact that it is represented only by dental remains, its place in mammalian evolution has been debated, but consensus has leaned toward its classification as as a primate, explains in a press release paleontologist Kathleen Rust, of the Biodiversity Institute at the University of Kansas, and lead author of the work published in the Journal of Human Evolution (New window) (in English).
Landmarks
Ekgmowechashala means little human cat in the Sioux language. It belonged to the suborder Adapiformes, primitive primates which are now extinct. The first fossils were discovered in the 1960s.
North American monkeys
The first North American primates appeared about 56 million years ago and thrived on the continent for more than 20 million years. They then all disappeared 34 million years ago, when the planet became colder and drier, making the continent inhospitable to these animals usually fond of heat.
Or, Ekgmowechashala appears in the fossil record of the Great Plains more than 4 million years after the extinction of all other North American ape species.
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Fossilized teeth of Ekgmowechashala
Photo: University of Kansas
To try to understand what may seem like an anomaly, the Chinese-American team of paleontologists wanted to reconstruct the family tree ofEkgmowechashala. To do this, Kathleen Rust and her colleagues at the University of Kansas and the Beijing Institute of Vertebrate Paleontology analyzed fossilized teeth and jaws unearthed in Nebraska in the 1960s and other eerily similar fossils. discovered in the 1990s in the Guangxi region of China.
We assembled a large body of morphological data to create an evolutionary tree that shows a close relationship between Ekgmowechashala from North America and fossils from China.
Thus, according to paleontologists, the presence ofEkgmowechashala in North America would not be the result of the evolution of an older primate that adapted to the cooler, drier conditions that led to the extinction of other primates on the continent.
According to Kathleen Rust, the ancestors ofEkgmowechashala would rather have come from a species that arrived from Asia via the Bering Strait millions of years later, according to certain scenarios similar to that of the arrival of the first humans.
Furthermore, the simultaneous presence ofEkgmowechashala in Oregon and the Great Plains indicates that the last nonhuman primates became extinct in North America about 26 million years ago, the study authors note.
Risen from the dead
Species like Ekgmowechashalawhich suddenly appear in the fossil record long after their parents have disappeared, are called Lazarus taxa, in reference to the biblical character who was raised from the dead by Jesus.
Following the disappearance ofEkgmowechashalano species of primates populated the North American continent for more than 25 million years, until the arrival of the first A wise man.
The arrival of humans in North America marked the third chapter in the history of primates on this continent. Like EkgmowechashalaNorth American humans are a prime example of the Lazarus Effect.
Adapt or disappear
Paleontologist Kathleen Rust believes that the history ofEkgmowechashala deserves to be told because it took place at a time marked by profound environmental and climatic changes, like ours, due to human activity.
It is essential to understand how extinct species responded to such changes. In such situations, organisms usually adapt by retreating to more hospitable regions with resources, or they are threatened with extinction.
This is precisely what happened about 34 million years ago, when not all North American primate species were able to adapt to survive.
North America did not have the conditions necessary for their survival. This highlights the importance of resource accessibility for our non-human primate relatives (bonobos, chimpanzees and gorillas) in times of radical climate change, adds Kathleen Rust.
Understanding this narrative not only humbles us, but also helps us appreciate the depth and complexity of the dynamic planet we inhabit.
It allows us to understand the complex workings of nature, the power of evolution in the appearance of life and the influence of environmental factors, notes the American paleontologist.
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