Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Recently analyzed fossil was not human ancestor as claimed, anthropologists say

03.03.2010
Darwinius was ancestor to lemurs and lorises, research shows

A fossil that was celebrated last year as a possible "missing link" between humans and early primates is actually a forebearer of modern-day lemurs and lorises, according to two papers by scientists at The University of Texas at Austin, Duke University and the University of Chicago.

In an article now available online in the Journal of Human Evolution, four scientists present evidence that the 47-million-year-old Darwinius masillae is not a haplorhine primate like humans, apes and monkeys, as the 2009 research claimed.

They also note that the article on Darwinius published last year in the journal PLoS ONE ignores two decades of published research showing that similar fossils are actually strepsirrhines, the primate group that includes lemurs and lorises.

"Many lines of evidence indicate that Darwinius has nothing at all to do with human evolution," says Chris Kirk, associate professor of anthropology at The University of Texas at Austin. "Every year, scientists describe new fossils that contribute to our understanding of primate evolution. What's amazing about Darwinius is, despite the fact that it's nearly complete, it tells us very little that we didn't already know from fossils of closely related species."

His co-authors are anthropologists Blythe Williams and Richard Kay of Duke and evolutionary biologist Callum Ross of the University of Chicago. Williams, Kay and Kirk also collaborated on a related article about to be published in the Proceedings of the National Academy of Sciences that reviews the early fossil record and anatomical features of anthropoids – the primate group that includes monkeys, apes, and humans.

Last spring's much-publicized article on Darwinius was released in conjunction with a book, a History Channel documentary, and an exhibit in the American Museum of Natural History. At a news conference attended by New York Mayor Michael Bloomberg, the authors unveiled the nearly complete fossil of a nine-month-old female primate that had been found at the site of Messel in Germany.

But other anthropologists were immediately skeptical of the conclusions and began writing the responses that are being published this month.

"Just because it's a complete and well-preserved fossil doesn't mean it's going to overthrow all our ideas," says Williams, the lead author. "There's this enormous body of literature that has built up over the years. The Darwinius research completely ignored that body of literature."

That literature centers on the evolution of primates, which include haplorhines (apes, monkeys, humans, tarsiers) and strepsirrhines (lemurs, lorises). The two groups split from each other nearly 70 million years ago.

The fossil group to which Darwinius belongs – the adapiforms – have been known since the early 1800s and includes dozens of primate species represented by thousands of fossils recovered in North America, Europe, Asia and Africa. Some adapiforms, like North American Notharctus, are known from nearly complete skeletons like that of Darwinius. Most analyses of primate evolution over the past two decades have concluded that adapiforms are strepsirrhines, and not direct ancestors of modern humans.

The most recent such analysis, published last year in the journal Nature, concluded that Darwinius is an early strepsirrhine and a close relative of the 39-million-year- old primate Mahgarita stevensi from West Texas.

Nevertheless, the scientists who last year formally described Darwinius concluded that it was an early haplorhine, and even suggested that Darwinius and other adapiform fossils "could represent a stem group from which later anthropoid primates evolved."

For example, they note that Darwinius has a short snout and a deep jaw – two features that are found in monkeys, apes, and humans.

However, Kirk, Williams and their colleagues point out that short snouts and deep jaws are known to have evolved multiple times among primates, including several times within the lemur/loris lineage. They further argue that Darwinius lacks most of the key anatomical features that could demonstrate a close evolutionary relationship with living haplorhines (apes, monkeys, humans, and tarsiers).

For instance, haplorhines have a middle ear with two chambers and a plate of bone that shields the eyes from the chewing muscles.

"There is no evidence that Darwinius shared these features with living haplorhines," says Kirk. "And if you can't even make that case, you can forget about Darwinius being a close relative of humans or other anthropoids."

For more information, please contact:
Chris Kirk, eckirk@mail.utexas.edu, 512 471 0056
Blythe Williams, blythe.williams@duke.edu, 919 660-7385
Gary Susswein, College of Liberal Arts,
susswein@austin.utexas.edu, 512-471-4945

Gary Susswein | EurekAlert!
Further information:
http://www.utexas.edu

More articles from Life Sciences:

nachricht Two Group A Streptococcus genes linked to 'flesh-eating' bacterial infections
25.09.2017 | University of Maryland

nachricht Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: LaserTAB: More efficient and precise contacts thanks to human-robot collaboration

At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.

Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Fraunhofer ISE Pushes World Record for Multicrystalline Silicon Solar Cells to 22.3 Percent

25.09.2017 | Power and Electrical Engineering

Usher syndrome: Gene therapy restores hearing and balance

25.09.2017 | Health and Medicine

An international team of physicists a coherent amplification effect in laser excited dielectrics

25.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>