Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Tree-climbing with dinosaurs

25.04.2002


Most mammals of this vintage are known only by their teeth.
© Nature


Fossil find hints at life of one of our earliest mammalian forebears.

A mouse-sized fossil from 125 million years ago is the earliest known member of the mammal group that includes humans, say researchers.

The animal is a primitive example of today’s dominant mammals. "It’s at the very root of this diverse and incredibly important group," says palaeontologist Zhe-Xi Luo of the Carnegie Museum of Natural History in Pittsburgh1.



The mammal, Eomaia scansoria, might have scampered up a tree as a feathered dinosaur ran past. The animal’s elongated digits suggest that it was adept at climbing; its name translates as ’dawn-mother climber’.

Luo and his colleagues discovered Eomaia in China. Its skeleton is exceptionally well preserved, and the fossil shows its dense fur. Most mammals of a similar vintage are known only by their teeth.

Eomaia’s teeth and ankle-bones mark it out as a member of the group called the Eutheria, rather than a marsupial or one of the egg-laying group called monotremes.

But Eomaia probably lacked a placenta, and would have reproduced in a similar way to modern marsupials. Its hips are too narrow to give birth to large young; its babies would have been born at an early stage of development and clung to their mother for shelter and nourishment.

Eomaia was discovered in a fossil lakebed. When it lived, the surrounding landscape would have been lush and densely vegetated. The animal’s teeth suggest that it ate insects, and it may have led a shrew-like life in bushes and trees.

Treasure trove

The rocks that hold Eomaia are a fossil treasure trove, containing many beautifully preserved animals, including feathered dinosaurs. There are also other mammals, ranging from beasts smaller than Eomaia to a predator slightly larger than a domestic cat. These other species seem to have been less well adapted for climbing.

"What’s so cool is that we’re beginning to get some sense of how these animals lived together," says palaeontologist Anne Weil of Duke University in Durham, North Carolina. Although, she warns, reconstructing fossils’ lives is "a bit of a guessing game".

Mammals were already a diverse group by this stage, adds palaeontologist Jerry Hooker of the Natural History Museum, London. "We must go back further to look for even older eutherians," to truly understand the evolution of early mammals, he says.

Fossils suggest that there were seven mammal lineages present at his time - our ancestors would have been "just another face in the crowd", says Weil. But only three of these groups survive today. Three died out while dinosaurs still roamed, the fourth about 35 million years ago.

Early marsupials - another lineage that survived and thrived - seem also to have been tree dwellers. An ability to climb might have given them, like Eomaia, the edge over their contemporaries, Weil suggests.

References
  1. Ji, Q. et al. The earliest eutherian mammal. Nature, 416, 816 - 822, (2002).


JOHN WHITFIELD | © Nature News Service

More articles from Life Sciences:

nachricht Bare bones: Making bones transparent
27.04.2017 | California Institute of Technology

nachricht Link Discovered between Immune System, Brain Structure and Memory
26.04.2017 | Universität Basel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

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...

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

Bare bones: Making bones transparent

27.04.2017 | Life Sciences

Study offers new theoretical approach to describing non-equilibrium phase transitions

27.04.2017 | Physics and Astronomy

From volcano's slope, NASA instrument looks sky high and to the future

27.04.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>