Print 53 comment(s) - last by callofduty1000.. on Apr 22 at 1:27 PM

Liaoconodon hui  (Source: Jin Meng)
A new fossil, Liaoconodon hui, was found in China and has all three middle ear bones

Researchers have discovered a complete mammalian fossil that includes a transitional middle ear, which consists of three bones that paleontologists have been searching for over 150 years.  

Jin Meng, study leader and curator in the Division of Paleontology at the American Museum of Natural History, along with Wang Yuanqing and Li Chuankui, both from the Institute of Vertebrate Paleontology and Paleoanthropology at the Chinese Academy of Sciences in Beijing, have found the first complete mammalian fossil that includes the transitional middle ear.

Mammals are defined as a class of air-breathing vertebrate animals that share characteristics like hair and mammary glands in mothers with young. They also share three middle ear bones called the malleus, incus and ectotympanic. Two of these bones are found in the joint of the lower jaw in reptiles, and researchers believe that an evolutionary shift from lizards to mammals separated the quadrate and articular plus prearticular bones from the posterior lower jaw, and they became associated with hearing as the malleus and the incus.

Previous fossils show early mammals with reptilian jaw joints and reductions in these bones for both chewing and hearing while other early mammalian fossils have ossified cartilage still connected to the groove on their lower jaws. But none of these fossils had the middle ear bones, and more evidence was needed to confirm this early transition and the mysteries of the mammalian middle ear. 

"People have been looking for this specimen for over 150 years since noticing a puzzling groove on the lower jaw of some early mammals," said Meng. "Now we have cartilage with ear bones attached, the first clear paleontological evidence showing relationships between the lower jaw and middle ear." 

The new fossil, which is called Liaoconodon hui, is a medium-sized mammal measuring 35.7 cm long. It dates from the Mesozoic (about 125 to 122 million years) and was named after the fossil beds in Liaoning, China, which is where it was discovered. It was also named after Yaoming Hu, who was a graduate of the American Museum of Natural History's doctoral program and passed away recently.  

Liaoconodon hui is complete, and shows researchers that the incus and malleus are detached from the lower jaw in order to create part of the middle ear. According to the study, the incus and the malleus "remain linked to the jaw by the ossified Meckel's cartilage that rests in the groove on the lower jaw," and the eardrum was stabilized with this cartilage as support. 

"Before we did not know the detailed morphology of how the bones of the middle ear detached, or the purpose of the ossified cartilage," said Meng. "Liaoconodon hui changes previous interpretations because we now know the detailed morphology of the transitional mammals and can propose that the ossified cartilage is a stabilizer."

This study also found that the middle ear "probably" evolved twice in monotremes, marsupials and placentals. This was determined by features associated with the groove on the lower jaw and other bones, including the presence of ossified Meckel's cartilage.  

This study was published in Nature.

Comments     Threshold

This article is over a month old, voting and posting comments is disabled

By gman7664 on 4/18/2011 2:39:52 PM , Rating: 2
Near as I can tell you are pretty similar to all the other folks that claim evolution is not valid.

Your comment about there never being enough fossils to make evolution work fails to take into account the parallel line of evidence being developed through researching the genomes of both living and fossilized species and which does contain such information.

As we progress on both fronts it is amazing how well these two tools fit together to demonstrate the mechanisms behind evolution. You seem to forget that evolution is an observed fact and that the theory is simply a description of how it all worked. The theory is quite well tested and is very complete, albeit not totally.

As our science investigates that which we can observe we refine our understanding of the subject.

Contrast this to any investigation of any god proposed by any human. Interestingly, the Universe at present contains a very large amount of information, much of which we have processed, yet nowhere is there a single bit of information about any such god. People do not hesitate to use god to explain things they do not understand but they fail to show that their god actually exists which is of course a prerequisite to being the explanation for something.

Were science to obtain any actual information about god then we can study the phenomena, but to date there is an utter absence of any such information. Even more interesting is that the Universe works quite well without any such god; our inability to understand it all does not make god responsible for the universe.

Evolutionary theory uses observable mechanisms to explain how evolution operated. In each and every case there is an observable cause and an observable effect. ID has no such observable cause and is used to explain things for which we either have an excellent explanation or will have shortly - ironically ID puts the spotlight on things that are poorly explained and by doing so attract the attention of some scientist that then proceeds to work out the mechanism behind the observation. Naturally this does not suit the ID proponents so they dismiss it but that does not invalidate the work.

Finally,what undermines Intelligent Design is that it solves a problem that does not exist. It is tacked on to things when the actual explanation does not suit someone that wants there to be a different explanation, typically involving a god they desperately want to exist in order to provide them with comfort.

Remember, kids, Science is the means by which we determine how the Universe actually is as opposed to how we want or beleive it to be.

Religion, on the other hand, is the means by which we convince ourselves the Universe is the way we want or beleive it to be as opposed to how it actually is.

I prefer the former to the latter as I do not find comfort in lying to myself.

"This week I got an iPhone. This weekend I got four chargers so I can keep it charged everywhere I go and a land line so I can actually make phone calls." -- Facebook CEO Mark Zuckerberg

Most Popular ArticlesFree Windows 10 offer ends July 29th, 2016: 10 Reasons to Upgrade Immediately
July 22, 2016, 9:19 PM
Top 5 Smart Watches
July 21, 2016, 11:48 PM

Copyright 2016 DailyTech LLC. - RSS Feed | Advertise | About Us | Ethics | FAQ | Terms, Conditions & Privacy Information | Kristopher Kubicki