Featured Research

from universities, journals, and other organizations

Prehistoric Reptiles From Russia Possessed The First Modern Ears

Date:
September 12, 2007
Source:
Public Library of Science
Summary:
Paleobiologists report that these fossil animals, found in deposits of Permian age near the Mezen River in central Russia, possessed all the anatomical features typical of a vertebrate with a surprisingly modern ear.

The 260 million-year-old fossil of the small reptile Bashkyroleter mesensis, from central Russia, owner of the first known 'modern' ear. Reconstruction (in pink, below) of the extremely large eardrum structure. Entire skull approximately 6.5 cm in length.
Credit: Linda Tsuji and Johannes Müller

The discovery of the first anatomically modern ear in a group of 260 million-year-old fossil reptiles significantly pushes back the date of the origin of an advanced sense of hearing, and suggests the first known adaptations to living in the dark.

In a new study published in PLoS One, Johannes Müller and Linda Tsuji, paleobiologists at the Natural History Museum of the Humboldt University in Berlin, Germany report that these fossil animals, found in deposits of Permian age near the Mezen River in central Russia, possessed all the anatomical features typical of a vertebrate with a surprisingly modern ear.

When vertebrates had conquered land and the ancestors of modern day mammals, reptiles, and birds first began to diversify, hearing was not of high importance. The first fully terrestrial land vertebrates were, in fact, largely deaf, and lacked any of the anatomical features that would indicate the possession of what is termed impedance-matching hearing - the mechanism by which modern land vertebrates are able to transmit airborne sounds into the inner ear by means of small bony connections.

The ability of modern animals to hear a wide range of frequencies, highly important for prey capture, escape, and communication, was long assumed to have only evolved shortly before the origin of dinosaurs, not much longer than 200 million years ago, and therefore comparatively late in vertebrate history.

But these fossils demonstrate that this advanced ear was in existence much earlier than previously suggested. In these small reptiles the outside of the cheek was covered with a large eardrum, and a bone comparable to our own hearing ossicles connected this structure with the inner ear and the brain. Müller and Tsuji also examined the functional performance of this unique and unexpected auditory arrangement, and discovered that these little reptiles were able to hear at least as well as a modern lizard.

But why would these animals have possessed such an ear" "Of course this question cannot be answered with certainty", explains Müller, "but when we compared these fossils with modern land vertebrates, we recognized that animals with an excellent sense of hearing such as cats, owls, or geckos, are all active at night or under low-light conditions.

And maybe this is what these Permian reptiles did too." Because the fossils from the Mezen River also possess comparatively large eyes, another typical feature of vertebrates living in the dark, these reptiles indeed might have been among the first land vertebrates to pursue a specifically nocturnal lifestyle. An adaptation of this kind would have been a significant step at this early stage of terrestrial evolution, as endothermic (cold-blooded) animals require the heat of the sun to maintain their body temperature.

The discovery of an ear comparable to modern-day standards in such ancient land vertebrates provides an entirely new piece of information about the earliest terrestrial ecosystems, which no longer seem to be as primitive as once assumed. Already by this time, there must have been intense pressure to exploit new ecological niches and to evolve new structures to gain an advantage over other species in an increasingly crowded world. At last, it was those pressures and evolutionary inventions that paved the way for our modern day environments.

Citation: Müller J, Tsuji LA (2007) Impedance-Matching Hearing in Paleozoic Reptiles: Evidence of Advanced Sensory Perception at an Early Stage of Amniote Evolution. PLoS ONE 2(9): e889. doi:10.1371/journal.pone.0000889


Story Source:

The above story is based on materials provided by Public Library of Science. Note: Materials may be edited for content and length.


Cite This Page:

Public Library of Science. "Prehistoric Reptiles From Russia Possessed The First Modern Ears." ScienceDaily. ScienceDaily, 12 September 2007. <www.sciencedaily.com/releases/2007/09/070911202506.htm>.
Public Library of Science. (2007, September 12). Prehistoric Reptiles From Russia Possessed The First Modern Ears. ScienceDaily. Retrieved September 3, 2014 from www.sciencedaily.com/releases/2007/09/070911202506.htm
Public Library of Science. "Prehistoric Reptiles From Russia Possessed The First Modern Ears." ScienceDaily. www.sciencedaily.com/releases/2007/09/070911202506.htm (accessed September 3, 2014).

Share This



More Fossils & Ruins News

Wednesday, September 3, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Did Neanderthals Play Tic-Tac-Toe?

Did Neanderthals Play Tic-Tac-Toe?

Newsy (Sep. 2, 2014) — Artwork found in a Gibraltar cave that was possibly done by Neanderthals suggests they may have been smarter than we all thought. Video provided by Newsy
Powered by NewsLook.com
Millions Of Historical Public Domain Photos Added To Flickr

Millions Of Historical Public Domain Photos Added To Flickr

Newsy (Aug. 30, 2014) — Historian Kalev Leetaru uploaded a large collection of historical photos, images that were previously difficult to collect. Video provided by Newsy
Powered by NewsLook.com
Minds Blown: Scientists Develop Fish That Walk On Land

Minds Blown: Scientists Develop Fish That Walk On Land

Newsy (Aug. 28, 2014) — Canadian scientists looking into the very first land animals took a fish out of water and forced it to walk. Video provided by Newsy
Powered by NewsLook.com
Huge Ancient Wine Cellar Found In Israel

Huge Ancient Wine Cellar Found In Israel

Newsy (Aug. 28, 2014) — An international team uncovered a large ancient wine celler that likely belonged to a Cannonite ruler. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins