Navigation Links
Chewing their way to success

The subfamily of rodents known as Murinae (mice, rats, etc.), which first appeared in Asia 12 million years ago, spread across the entire Old World (Eurasia, Africa, Australia) in less than 2 million years, a remarkably fast rate. Researchers have long suspected that one of the reasons for their evolutionary success is related to their unique masticatory apparatus. Now, researchers have used the brilliant X-ray beams produced at the European Synchrotron (ESRF) to study several hundred specimens, both extant and extinct, to describe the evolutionary processes that caused rats and mice to acquire this characteristic feature. The study was published in the journal Evolution on 28 November 2013.

The research team, from the Institut de Paloprimatologie, Palontologie Humaine: volution et Paloenvironnements (CNRS / Universit de Poitiers), was able to determine the diet of extinct species and to trace the evolutionary history of these rodents. Today, the Murinae comprise 584 species, which represents over 10% of the diversity of present day mammals.

In their study the researchers were able to identify two key evolutionary moments in the acquisition of this masticatory apparatus.

The first one occurred around 16 million years ago when the ancestors of the Murinae changed from a herbivorous diet to an insectivorous diet. This new diet was encouraged by the acquisition of chewing movements that are unusual in mammals, forwardly directed but continuing to interlock opposing teeth. This aquisition helped them reduce tooth erosion and better preserve pointed cusps, which are used to puncture the exoskeletons of insects.

Then, twelve million years ago, the very earliest Murinae returned to a herbivorous diet, while at the same time retaining their chewing motion. This also enabled them to use both their mandibles simultaneously during mastication. The change in diet gave way to the formation of three longitudinal rows of cusps on their teeth. Their ancestors, like other related rodents such as hamsters and gerbils, only have two rows, as do humans.

To reconstruct this series of evolutionary events, the scientists studied several hundred teeth belonging to extant or extinct rodents at the European Synchrotron (ESRF) in Grenoble. The team applied methods originally used in map-making to analyze 3D digital models of the dental morphology of these species. Comparison of the dental structures of present day and fossil rodents enabled them to determine the diet of the extinct species. In addition, studying the wear on their teeth allowed them to reconstruct the chewing motion, either directed forwardly or obliquely, of these animals.

The study traces the way in which evolution progresses by trial and error, ending up with a morphological combination that lies behind the astonishing evolutionary success of an animal family.

The innovative methods used by the researchers to analyze and compare masticatory systems could be used to study dietary changes in other extinct mammals. This might prove to be especially interesting with regard to primates, since, before the appearance of hominids, primates underwent several dietary changes that affected their subsequent evolutionary history.


Contact: Claus Habfast
European Synchrotron Radiation Facility

Related biology news :

1. How chewing gum or a shed hair can let strangers read your Book of Life
2. Older siblings cells can be passed from female dogs to their puppies in the womb, MU researchers find
3. Long-term memory helps chimpanzees in their search for food
4. Rats! Humans and rodents process their mistakes
5. Cells molecular muscles help them sense and respond to their environments
6. When cells eat their own power plants; Pitt scientists solve mystery of cellular process
7. Coastal animals have their own tidal timer -- separate from the 24-hour body clock
8. How bacteria integrate autotransporters into their outer membrane
9. UdeMs IRIC and IRICoR achieve important milestone in their collaboration with Bristol-Myers Squibb
10. Hypertension researcher encourages colleagues to expand their focus
11. Surprising underwater-sounds: Humpback whales also spend their winter in Antarctica
Post Your Comments:
Related Image:
Chewing their way to success
(Date:11/16/2015)... 2015  Synaptics Inc. (NASDAQ: SYNA ), ... announced expansion of its TDDI product portfolio with ... and display driver integration (TDDI) solutions designed to ... TDDI products add to the previously-announced TD4300 ... resolution), and TD4322 (FHD resolution) solutions. All four ...
(Date:11/11/2015)... --  MedNet Solutions , an innovative SaaS-based eClinical technology company ... to announce that it will be a Sponsor of the ... be held November 17-19 in Hamburg , ... iMedNet , MedNet,s easy-to-use, proven and affordable ... been able to deliver time and cost savings of up ...
(Date:11/9/2015)... JOSE, Calif. , Nov. 9, 2015  Synaptics ... human interface solutions, today announced broader entry into the ... vehicle-specific solutions that match the pace of consumer electronics ... and biometric sensors are ideal for the automotive industry ... vehicle. Europe , ...
Breaking Biology News(10 mins):
(Date:11/24/2015)... LUMPUR, Malaysia , Nov. 24, 2015 /PRNewswire/ ... global contract research organisation (CRO) market. The trend ... result in lower margins but higher volume share ... increased capacity and scale, however, margins in the ... Research Organisation (CRO) Market ( ), ...
(Date:11/24/2015)... Halozyme Therapeutics, Inc. (NASDAQ: HALO ) will be presenting at ... on Wednesday, December 2 at 9:30 a.m. ET/6:30 a.m. PT ... provide a corporate overview. th Annual Oppenheimer Healthcare ... ET/10:00 a.m. PT . Jim Mazzola , vice president ... --> th Annual Oppenheimer Healthcare Conference in ...
(Date:11/24/2015)... (PRWEB) , ... November 24, 2015 , ... ... event of the year and one of the premier annual events for pharmaceutical ... ran from 8–11 November 2015, where ISPE hosted the largest number of attendees ...
(Date:11/24/2015)... PUNE, India , November 24, 2015 ... to a new market research report "Oligonucleotide Synthesis Market ... Equipment), Application (PCR, Gene Synthesis, Diagnostic, DNA, RNAi), End-User ... to 2020", published by MarketsandMarkets, the market is expected ... 1,078.1 Million in 2015, at a CAGR of 10.1% ...
Breaking Biology Technology: