ESCONI June 2024 General Meeting – June 14th, 2024 at 8:00 PM via Zoom – “A North American fossil primate called Ekgmowechashala”

The June 2024 General Meeting will be held on June 14th, 2024 via Zoom.  The presentation is by Kathleen Rust of the University of Kansas.  She will be speaking about Ekgmowechashala, a primate known only from the late early Oligocene of western North America.

I am planning on presenting findings from my most recent publication describing a new primate species from the late Eocene of China that we named Palaeohodites and how its discovery elucidates the origin of a very funky primate species from the Oligocene of North America called Ekgmowechashala. My talk is about 30-40 mins. I will most certainly make time for questions from the audience.

Here’s a link to an an article about her recent paper on the subject.

Fossils tell tale of last primate to inhabit North America before humans

The story of Ekgmowechashala, the final primate to inhabit North America before Homo sapiens or Clovis people, reads like a spaghetti western: A grizzled and mysterious loner, against the odds, ekes out an existence on the American Plains.

Except this tale unfolded about 30 million years ago, just after the Eocene-Oligocene transition during which North America saw great cooling and drying, making the continent less hospitable to warmth-loving primates.

Today, paleontologists from the University of Kansas and the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing have published evidence in the Journal of Human Evolution shedding light on the long-standing saga of Ekgmowechashala, based on fossil teeth and jaws found in both Nebraska and China.

Phylogeny and paleobiogeography of the enigmatic North American primate Ekgmowechashala illuminated by new fossils from Nebraska (USA) and Guangxi Zhuang Autonomous Region (China)

Abstract

Ekgmowechashala is a poorly documented but very distinctive primate known only from the late early Oligocene (early Arikareean) of western North America. Because of its highly autapomorphous dentition and spatiotemporal isolation, the phylogenetic and biogeographic affinities of Ekgmowechashala have long been debated. Here, we describe the oldest known fossils of Ekgmowechashala from the Brown Siltstone Beds of the Brule Formation, White River Group of western Nebraska. We also describe a new ekgmowechashaline taxon from the Nadu Formation (late Eocene) in the Baise Basin of Guangxi Zhuang Autonomous Region in southern China. Phylogenetic analysis suggests that North American  Ekgmowechashala and the new Chinese taxon are sister taxa that are nested within a radiation of southern Asian adapiforms that also includes GatanthropusMuangthanhinius, and Bugtilemur. The new Chinese ekgmowechashaline helps fill the considerable disparity in dental morphology between Ekgmowechashala and more primitive ekgmowechashalids known from southern Asia. Our study underscores the fundamental role of southern Asia as a refugium for multiple primate clades during the cooler and drier climatic regime that prevailed after the Eocene–Oligocene transition. The colonization of North America by Ekgmowechashala helps define the beginning of the Arikareean Land Mammal Age and corresponds to an example of the Lazarus effect, whereby a taxon (in this case, the order Primates) reappears suddenly in the fossil record after a lengthy hiatus.

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