Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Paleontologists discover most primitive primate skeleton

25.01.2007
The origins and earliest branches of primate evolution are clearer and more ancient by 10 million years than previous studies estimated, according to a study featured on the cover of the Jan. 23 print edition of the Proceedings of the National Academy of Sciences.

The paper by researchers at Yale, the University of Winnipeg, Stony Brook University, and led by University of Florida paleontologist Jonathan Bloch reconstructs the base of the primate family tree by comparing skeletal and fossil specimens representing more than 85 modern and extinct species. The team also discovered two 56-million-year-old fossils, including the most primitive primate skeleton ever described.

In the two-part study, an extensive evaluation of skeletal structures provides evidence that plesiadapiforms, a group of archaic mammals once thought to be more closely related to flying lemurs, are the most primitive primates. The team analyzed 173 characteristics of modern primates, tree shrews, flying lemurs with plesiadapiform skeletons to determine their evolutionary relationships. High-resolution CT scanning made fine resolution of inaccessible structures inside the skulls possible.

"This is the first study to bring it all together," said co-author Eric Sargis, associate professor of anthropology at Yale University and Assistant Curator of Vertebrate Zoology at Yale's Peabody Museum of Natural History. "The extensive dataset, the number and type of characteristics we were able to compare, and the availability of full skeletons, let us test far more than any previous study."

At least five major features characterize modern primates: relatively large brains, enhanced vision and eyes that face forward, a specialized ability to leap, nails instead of claws on at least the first toes, and specialized grasping hands and feet. Plesiadapiforms have some but not all of these traits. The article argues that these early primates may have acquired the traits over 10 million years in incremental changes to exploit their environment.

While the study did not include a molecular evaluation of the samples, according to Sargis, these results are consistent with molecular studies on related living groups. Compatibility with the independent molecular data increases the researchers' confidence in their own results.

Bloch discovered the new plesiadapiform species, Ignacius clarkforkensis and Dryomomys szalayi, just outside Yellowstone National Park in the Bighorn Basin with co-author Doug Boyer, a graduate student in anatomical sciences at Stony Brook. Previously, based only on skulls and isolated bones, scientists proposed that Ignacius was not an archaic primate, but instead a gliding mammal related to flying lemurs. However, analysis of a more complete and well-preserved skeleton by Bloch and his team altered this idea.

"These fossil finds from Wyoming show that our earliest primate ancestors were the size of a mouse, ate fruit and lived in the trees," said study leader Jonathan Bloch, a vertebrate paleontology curator at the Florida Museum of Natural History. "It is remarkable to think we are still discovering new fossil species in an area studied by paleontologists for over 100 years."

Researchers previously hypothesized plesiadapiforms as the ancestors of modern primates, but the idea generated strong debate within the primatology community. This study places the origins of Plesiadapiforms in the Paleocene, about 65 (million) to 55 million years ago in the period between the extinction of the dinosaurs and the first appearance of a number of undisputed members of the modern orders of mammals.

"Plesiadapiforms have long been one of the most controversial groups in mammalian phylogeny," said Michael J. Novacek, curator of paleontology at the American Museum of Natural History. "First, they are somewhere near primates and us. Second, historically they have offered tantalizing, but very often incomplete, fossil evidence. But the specimens in their study are beautifully and spectacularly preserved."

"The results of this study suggest that plesiadapiforms are the critical taxa to study in understanding the earliest phases of human evolution. As such, they should be of very broad interest to biologists, paleontologists, and anthropologists," said co-author Mary Silcox, professor of anthropology at the University of Winnipeg.

"This collaboration is the first to bring together evidence from all regions of the skeleton, and offers a well-supported perspective on the structure of the earliest part of the primate family tree," Bloch said.

Janet Rettig Emanuel | EurekAlert!
Further information:
http://www.yale.edu

More articles from Studies and Analyses:

nachricht New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

nachricht Reusable carbon nanotubes could be the water filter of the future, says RIT study
30.03.2017 | Rochester Institute of Technology

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

Im Focus: Quantum-physical Model System

Computer-assisted methods aid Heidelberg physicists in reproducing experiment with ultracold atoms

Two researchers at Heidelberg University have developed a model system that enables a better understanding of the processes in a quantum-physical experiment...

Im Focus: Glacier bacteria’s contribution to carbon cycling

Glaciers might seem rather inhospitable environments. However, they are home to a diverse and vibrant microbial community. It’s becoming increasingly clear that they play a bigger role in the carbon cycle than previously thought.

A new study, now published in the journal Nature Geoscience, shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

New quantum liquid crystals may play role in future of computers

21.04.2017 | Physics and Astronomy

A promising target for kidney fibrosis

21.04.2017 | Health and Medicine

Light rays from a supernova bent by the curvature of space-time around a galaxy

21.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>