Navigation Links
Paleontologists discover new mammal from Mesozoic Era

An international team of American and Chinese paleontologists has discovered a new species of mammal that lived 125 million years ago during the Mesozoic Era, in what is now the Hebei Province in China.

The new mammal, documented in the March 15 issue of the journal Nature, provides first-hand evidence of early evolution of the mammalian middle ear--one of the most important features for all modern mammals. The discovery was funded by the National Science Foundation (NSF).

"This early mammalian ear from China is a rosetta-stone type of discovery which reinforces the idea that development of complex body parts can be explained by evolution, using exquisitely preserved fossils," said H. Richard Lane, program director in NSF's Division of Earth Sciences, which co-funded the discovery with NSF's Division of Environmental Biology and its Assembling the Tree of Life (AToL) program.

Named Yanoconodon allini after the Yan Mountains in Hebei, the fossil was unearthed in the fossil-rich beds of the Yixian Formation and is the first Mesozoic mammal recovered from Hebei. The fossil site is about 300 kilometers outside of Beijing.

The researchers discovered that the skull of Yanoconodon revealed a middle ear structure that is an intermediate step between those of modern mammals and those of near relatives of mammals, also known as mammaliaforms.

"This new fossil offers a rare insight in the evolutionary origin of the mammalian ear structure," said Zhe-Xi Luo, a paleontologist at the Carnegie Museum of Natural History (CMNH) in Pittsburgh, Pa. "Evolution of the ear is important for understanding the origins of key mammalian adaptations."

Mammals have highly sensitive hearing, far better than the hearing capacity of all other vertebrates, scientists have found. Consequently, paleontologists and evolutionary biologists have been searching for more than a century for clues to the evolutionary origins of mammal ear structure.

Mammalian hearing adaptation is made possible by a sophisticated middle ear of three tiny bones, known as the hammer (malleus), the anvil (incus) and the stirrup (stapes), plus a bony ring for the eardrum (tympanic membrane).

The mammal middle ear bones evolved from the bones of the jaw hinge in their reptilian relatives. However, paleontologists long have attempted to understand the evolutionary pathway via which these precursor jaw bones became separated from the jaw and moved into the middle ear of modern mammals.

"Now we have a definitive piece of evidence, in a beautifully preserved fossil split on two rock slabs," said Luo. "Yanoconodon clearly shows an intermediate condition in the evolutionary process of how modern mammals acquired their middle ear structure."

Yanoconodon is about 5 inches (or 15 cm) long and estimated to weigh about 30 grams. Its teeth are notable for the three cusps in a straight line on molars (thus known as a triconodont) for feeding on insects and worms. It has a long body, short and sprawling limbs and claws that were ideal for either digging or living on the ground.

In addition to its unique ear structure, Yanoconodon also has a surprisingly high number of 26 thoracic ("chest") and lumbar ("waist") vertebrae, unlike most living and extinct terrestrial mammals that commonly have 19 or 20 thoracic and lumbar vertebrae. The extra vertebrae give Yanoconodon a more elongated body form, in contrast to its relatively shorter and very primitive limb and foot structures. The new mammal also has lumbar ribs, a rare feature among modern mammals.

"The discoveries of exquisitely preserved Mesozoic mammals from China have built the evidence such that biologists and paleontologists are able to make sense of how developmental mechanisms have impacted the morphological evolution of the earliest mammals," said Luo.
'"/>

Source:National Science Foundation


Related biology news :

1. Paleontologists learn how not to become a fossil
2. UAB scientists discover the origin of a mysterious physical force
3. Researchers discover way to make cells in the eye sensitive to light
4. Protein discovery could unlock the secret to better TB treatment
5. Newly-discovered class of genes determines ?and restricts ?stem cell fate
6. Newly discovered virus linked to childhood lung disorders and Kawasaki disease
7. Purdue proves concept of using nano-materials for drug discovery
8. Scientists discover the cellular roots of graying hair
9. Researchers discover molecule that causes secondary stroke
10. Scientists discover unique microbe in Californias largest lake
11. New protein discovered by Hebrew University researchers

Post Your Comments:
*Name:
*Comment:
*Email:


(Date:4/11/2017)... Research and Markets has announced the addition of the ... ... grow at a CAGR of 30.37% during the period 2017-2021. ... prepared based on an in-depth market analysis with inputs from industry ... over the coming years. The report also includes a discussion of ...
(Date:4/11/2017)... 2017 NXT-ID, Inc. (NASDAQ:   NXTD ... the appointment of independent Directors Mr. Robin D. Richards ... of Directors, furthering the company,s corporate governance and expertise. ... Gino Pereira , Chief ... to their guidance and benefiting from their considerable expertise as ...
(Date:4/5/2017)...  The Allen Institute for Cell Science today announces ... portal and dynamic digital window into the human cell. ... application of deep learning to create predictive models of ... a growing suite of powerful tools. The Allen Cell ... publicly available resources created and shared by the Allen ...
Breaking Biology News(10 mins):
(Date:9/19/2017)... ... , ... VetStem Biopharma ’s CEO and founder, Dr. Bob Harman DVM, MPVM, is featured ... Cell Therapy: A Rising Tide". Dr. Harman and Dr. Riordan met in 2003 and ... in the potential of stem cell therapy and a fast friendship was formed. , Dr. ...
(Date:9/19/2017)... , ... September 19, 2017 , ... ... biological outbreak is about to be eliminated, said Lyle Probst, President, CEO and ... FireflyDX™ technologies different than other pathogen detection solutions, Probst said, “Sample preparation ...
(Date:9/19/2017)... ... September 19, 2017 , ... Avomeen Analytical Services, ... of its 2017 Science Student Award. The scholarship program is dedicated to helping ... service defray the costs of obtaining their science education. , Avomeen began the ...
(Date:9/19/2017)... ... September 19, 2017 , ... ... Department of Financial Services (NYS DFS) cybersecurity regulations have transitioned into ... and insurance organizations operating in the state (“Covered Entities”) to conduct an ...
Breaking Biology Technology: