The tale of Ekgmowechashala , the last primate to roam North America before the arrival of Homo sapiens or Clovis people, unfolds like a classic Western film: A weathered and enigmatic individual, defying all odds, manages to survive on the vast American Plains.
Around 30 million years ago, during the Eocene-Oligocene transition, a time when North America underwent significant cooling and drying, making the continent less suitable for primates that thrived in warmer climates, the remarkable story of Ekgmowechashala, the last primate to inhabit North America before the arrival of Homo sapiens or Clovis people, comes to light.
Now, a team of paleontologists from the University of Kansas and the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing has published groundbreaking evidence in the Journal of Human Evolution, shedding new light on the age-old mystery surrounding Ekgmowechashala. This revelation is based on fossilized teeth and jaw specimens discovered in both Nebraska and China.
To unveil this ancient tale, the researchers embarked on a quest to reconstruct the primate’s family tree. This task was significantly aided by the discovery of an even more ancient Chinese “sister taxon” of Ekgmowechashala, which they have named Palaeohodites, signifying the “ancient wanderer.” The Chinese fossil finding helped resolve the enigma of Ekgmowechashala’s presence in North America, establishing that it was an immigrant rather than the result of local evolution. The tale of Ekgmowechashala
Kathleen Rust, the lead author and a doctoral candidate in paleontology at KU’s Biodiversity Institute and Natural History Museum, explained the significance of the project: “This project focuses on a very distinctive fossil primate known to paleontologists since the 1960s. 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 4 million years after the extinction of all other North American primates, which occurred around 34 million years ago.”
In the 1990s, Chris Beard, Rust’s doctoral adviser and co-author, KU Foundation Distinguished Professor and senior curator of vertebrate paleontology, collected fossils in the Nadu Formation in the Baise Basin in Guangxi, China, which closely resembled the Ekgmowechashala specimens known from North America. Beard recalled, “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. Here in KU’s collection, we have some critical fossils, including what is still by far the best upper molar of Ekgmowechashala known from North America. That upper molar is so distinctive and looks quite similar to the one from China that we found that it kind of seals the deal.” The tale of Ekgmowechashala
The responsibility of conducting the morphological analysis to establish the evolutionary relationships between Ekgmowechashala and its Chinese cousin Palaeohodites on a phylogenetic tree was entrusted to Rust.