But new research using the latest evidence suggests a completely different migration path from those previously proposed and indicates that sudden, rapid global warming drove the dispersal.
Researchers from the University of Michigan, Johns Hopkins University School of Medicine and the Royal Belgian Institute of Natural Sciences present their findings in the July 25 issue of the Proceedings of the National Academy of Sciences.
Their work focuses on Teilhardina, an ancient genus that resembled the saucer-eyed, modern-day primates known as tarsiers. Like tarsiers, monkeys, apes and humans, Teilhardina was a true primate, or euprimate. In both Asia and Europe, the genus is the oldest known primate; in North America, it appears in the fossil record around the same time as another primate, Cantius. Previously, scientists had come up with four ways to explain the geographic distribution pattern.
The first is that primates originated in Africa and spread across Europe and Greenland to reach North America. Another possibility is that they originated in North America and traveled across a temporary land bridge connecting Siberia and Alaska. A third hypothesis is that primates had their origins in Africa or Asia and traveled through North America to reach western Europe. Finally, it has been suggested that the group originated in Asia and fanned out eastward to North America and westward to Europe.
In the new research, U-M paleontologist Philip Gingerich and coworkers re-evaluated the four hypotheses by comparing with unprecedented precision the times of first appearance of Teilhardina in Asia, Europe, and North America. To achieve such precision, they used a carbon isotope curve recently documented on all three continents. Carbon in the atmosphere, earth and living organisms differs in the proportion of carbon-12 and carbon-13 present. A flood of carbon-12 is associated with the onset of an event known as the Paleocene-Eocene thermal maximum (PETM), one of the most rapid and extreme global warming events recorded in geologic history. It was during the PETM that modern primates first appeared 55 million years ago. Teilhardina in Asia precedes the maximum flood of carbon-12, Teilhardina in Europe coincides with it, and Teilhardina in North America appears just after the maximum. Based on this evidence, the researchers concluded that none of previously proposed scenarios was likely. Instead, they propose that Teilhardina migrated from South Asia to Europe, crossing the Turgai Straits---an ancient seaway between Europe and Asia---and then spread to North America by way of Greenland.
The whole dispersal event happened within about 25,000 years.
"It is remarkable to be able to study evolutionary events so deep in the past with such precision," said Gingerich, who is the Ermine Cowles Case Collegiate Professor of Paleontology and director of the U-M Museum of Paleontology. "The speed of dispersal and the speed of evolutionary change during dispersal are near the maximum for such rates observed today, and the rapid change and dispersal were almost certainly driven by profound greenhouse warming at the Paleocene-Eocene boundary."
100 % Organic Farming in Bhutan – a Realistic Target?
15.06.2018 | Humboldt-Universität zu Berlin
What the size distribution of organisms tells us about the energetic efficiency of a lake
05.06.2018 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.
Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...
The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.
Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.
An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.
Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...
Light detection and control lies at the heart of many modern device applications, such as smartphone cameras. Using graphene as a light-sensitive material for...
Water molecules exist in two different forms with almost identical physical properties. For the first time, researchers have succeeded in separating the two forms to show that they can exhibit different chemical reactivities. These results were reported by researchers from the University of Basel and their colleagues in Hamburg in the scientific journal Nature Communications.
From a chemical perspective, water is a molecule in which a single oxygen atom is linked to two hydrogen atoms. It is less well known that water exists in two...
13.06.2018 | Event News
08.06.2018 | Event News
05.06.2018 | Event News
18.06.2018 | Earth Sciences
18.06.2018 | Process Engineering
18.06.2018 | Life Sciences