The last primate to inhabit America before humans took the same path across the Being Strait into the continent millions of years earlier, a new study reveals.
The elusive Ekgmowechashala has been likened to a character from a spaghetti western, a mysterious loner eking out a living on the plains.
Experts from the University of Kansas have shed new light on the creature that lived 30 million years ago, just after the Eocene-Oligocene transition during which North America saw great cooling and drying.
They discovered that Ekgmowechashala did not descend from an older North American primate that somehow survived the cooler and drier conditions.
Instead it crossed over the Bering Strait millions of years after other American primates became extinct, anticipating the route followed by the first Native Americans much later in time.
Along with colleagues from the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing the team studied fossil teeth and jaws found in both Nebraska and China.
After reconstructing its family tree, the team discovered an even more ancient Chinese “sister taxon” of Ekgmowechashala the team has named Palaeohodites or “ancient wanderer”.
The Chinese fossil discovery shows it was an immigrant rather than the product of local evolution, according to the study published in the Journal of Human Evolution.
Doctoral student and study author Kathleen Rust said: “Due to its unique morphology and its representation only by dental remains, its place on the mammalian evolutionary tree has been a subject of contention and debate.
“There’s been a prevailing consensus leaning towards its classification as a primate but the timing and appearance of this primate in the North American fossil record are quite unusual.
“It appears suddenly in the fossil record of the Great Plains more than four million years after the extinction of all other North American primates, which occurred around 34 million years ago.”
Co-author Professor co-author Chris Beard collected fossils from the Nadu Formation in the Baise Basin in Guangxi, China, that closely resembled the enigmatic Ekgmowechashala.
He said: “When we were working there, we had absolutely no idea that we would find an animal that was closely related to this bizarre primate from North America, but literally as soon as I picked up the jaw and saw it, I thought, ‘Wow, this is it’.
“It’s not like it took a long time, and we had to undertake all kinds of detailed analysis — we knew what it was.”
The team then established the evolutionary relationships between Ekgmowechashala and its cousin Palaeohodites from China.
Rust said: “We collected a substantial amount of morphological data to create an evolutionary tree using a phylogenetic reconstruction software and algorithm.
This evolutionary tree suggests a close evolutionary relationship between North American Ekgmowechashala and Palaeohodites from China.The results from our analysis unequivocally supports this hypothesis.
“Our analysis dispels the idea that Ekgmowechashala is a relic or survivor of earlier primates in North America.
“Instead, it was an immigrant species that evolved in Asia and migrated to North America during a surprisingly cool period, most likely via Beringia.”
Species like Ekgmowechashala that show up suddenly in the fossil record long after their relatives have died off are referred to as “Lazarus taxa” after the biblical figure who was raised from the dead.
Prof. Beard added: “The ‘Lazarus effect’ in paleontology is when we find evidence in the fossil record of animals apparently going extinct — only to reappear after a long hiatus, seemingly out of nowhere.
“This is the grand pattern of evolution that we see in the fossil record of North American primates.
“The first primates came to North America about 56 million years ago at the beginning of the Eocene, and they flourished on this continent for more than 20 million years.
“But they went extinct when climate became cooler and drier near the Eocene-Oligocene boundary, about 34 million years ago.
“Several million years later Ekgmowechashala shows up like a drifting gunslinger in a Western movie, only to be a flash in the pan as far as the long trajectory of evolution is concerned.
“After Ekgmowechashala is gone for more than 25 million years, Clovis people come to North America, marking the third chapter of primates on this continent.
“Like Ekgmowechashala, humans in North America are a prime example of the Lazarus effect.”
According to Rust, the tale of Ekgmowechashala happened in an era of profound environmental and climatic changes, much like our own that’s driven by human activity.
She said: “It’s crucial to comprehend how past biota reacted to such shifts.
“In such situations, organisms typically either adapt by retreating to more hospitable regions with available resources or face extinction.
“Around 34 million years ago, all of the primates in North America couldn’t adapt and survive.
“North America lacked the necessary conditions for survival. This underscores the significance of accessible resources for our non-human primate relatives during times of drastic climatic change.
“Understanding this narrative is not only humbling, but also helps us appreciate the depth and complexity of the dynamic planet we inhabit,.
“It allows us to grasp the intricate workings of nature, the power of evolution in giving rise to life and the influence of environmental factors.”
Produced in association with SWNS Talker
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