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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.

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RE: Why Bother?
By JasonMick on 4/18/2011 6:22:25 PM , Rating: 2
Sure pal…

I'm not your pal, buddy.

Take whatever high road you’d like. Every week there is another article thrown up with some tenuous connection to the theory of evolution in hopes that it sparks endless bickering about evolution vs. religion that runs hundreds of posts long.

I find it funny how people complain about research into evolution and the news coverage thereof, when often in the same breath they go on to complain about the supposed "lack of evidence" (fossils, etc.) supporting evolution.

The gaps are filling in. Isn't that worth covering?

What’s next, you’ll print a highbrow article about how humans used to have spiny penises…?

No I think we covered that already (well not humans, technically, but our evolutionary precursors).

Do you see a problem with that?

Let me just add that you may not like this article for whatever reason (the debate that it causes, etc.), but at the end of the day it is a study published in what is perhaps science's most prestigious journal.

I certainly think that this study has a ton of merit and is worth covering.

I'm very sorry you don't agree -- but I do have to ask. If you feel that way, why did you come here and read it and leave all these comments? :)

RE: Why Bother?
By Reclaimer77 on 4/18/11, Rating: -1
RE: Why Bother?
By JonnyDough on 4/19/2011 12:54:37 AM , Rating: 1
Radioactive material doesn't become inert over long periods of time either. I think I'm seeing a trend seem to believe that the universe is static and not dynamic. I believe you are limiting yourself by not considering infinite possibilities in an unlimited universe.

Those who believe in God I ask this:

Why is it so hard to believe in an endless, timeless universe? Why do you feel compelled to believe in an endless timeless God with all the knowledge to create such a universe? Is that not just adding an additional and absolutely unprovable/illogically theorized complex layer on top of what we already see as truth? The universe exists. We both take that as fact. God exists, you rely on "belief, faith, emotion" and you take that as fact.

Which do we both concur on? It must be true. The universe exists.

So if we take that as a truth, then we must believe that within the universe there can come "intelligence" (ie creation, such as the birth of more humans) but can intelligence (ie creation) create a universe out of nothingness? Seems to be a farther stretch of my imagination...perhaps you and your God have powers that the average limited man doesn't have.

Why humans believe themselves to be some sort of demigods rather than animals I do not know. We are made of earth, and we rely on it for survival. If only more people realized we are not "above" nature. Last time I checked, a polar bear could eat things that you couldn't, survive places you couldn't, and kick your ass in a fist fight. So you have centuries of learning that you can borrow from and hold a gun in your hand. Big whoop. Human beings are not superior nature. They merely have a superior ability. It's time we start to understand that.

RE: Why Bother?
By Reclaimer77 on 4/19/11, Rating: 0
RE: Why Bother?
By LRonaldHubbs on 4/19/2011 8:07:20 AM , Rating: 1
If you don't believe in Creationism, and you also don't believe in evolution of species, then what exactly do you believe?

RE: Why Bother?
By safcman84 on 4/19/2011 4:45:11 AM , Rating: 2
What kind of evolution do you believe in then?

single cell life --> multi-cellular life --> diversify into the hundreds of different plants and animals you see today through evolution.

Maybe I misunderstood you but:
Mammals evolved from something, why cant it be from a reptile? it is not a evolutionary leap, but gradual evolution from reptile to mammal, it only seems to be a "leap" as not every single process in the evolution from reptile to mammal has found in the fossil record, so we have gaps and missing links. this fossil fills one of the gaps in, but not all of them -> the remaining gaps make it look like a leap, but that is far from the case.

RE: Why Bother?
By Reclaimer77 on 4/19/11, Rating: 0
RE: Why Bother?
By Paj on 4/19/2011 8:32:10 AM , Rating: 1
How can you believe in evolution, yet deny macroevolution? All youre doing is demonstrating your lack of knowledge.

Why do humans have a tailbone? Wisdom teeth, that can cause pain and death if not removed? Seems like an oversight at best, a poor design at worst. Furthermore, why do dolphins and whales have lungs if they live in the water? Who would design an animal in this way?

Isn't it possible that two species can have the same type of ear bones WITHOUT being related to each other? Is there any other evidence besides the ear bones that we're looking at a distant relative here?

Yes, it is. Its called convergent evolution, where the same biological trait is acquired in unrelated lineages. ie wovles and the (now extinct) Tasmainian Tiger share many common characteristics, despite being unrelated biologically or genetically.

RE: Why Bother?
By Reclaimer77 on 4/19/11, Rating: 0
RE: Why Bother?
By Fritzr on 4/19/2011 7:51:14 PM , Rating: 2
Quite easily. I don't. Our thoughts shape the universe, do they not? It always matters what we think.

If you believe that thinking beings created modern humans by shaping the universe with their thoughts, then yes I would include you with the Flat Earthers who deny that ships disappear over the horizon as they sail away.
This is still a very health debate on macro evolution in scientific circles, so please don't pretend that I'm some wacko claiming the Earth is flat.

If you actually read the article you would know that the discovery documents support of your theory of gradual change.

RE: Why Bother?
By Reclaimer77 on 4/19/2011 9:47:07 PM , Rating: 2
If you believe that thinking beings created modern humans by shaping the universe

Not exactly what I meant, and I think you know that. But okay, moving on...

If you actually read the article you would know that the discovery documents support of your theory of gradual change.

Then hoooray. Go me!

RE: Why Bother?
By Fritzr on 4/19/2011 7:45:48 PM , Rating: 2
I believe in micro evolution. That a species can adapt etc etc, you know the deal.

I do NOT believe that frogs can become dogs, or dogs can become man. I do not believe in macro evolution. Also this crackpot theory about how all the dinosaurs "evolved" into birds and one of those birds became a primate and that primate became, eventually, man....I mean, give me a break. You really buy that crap?

So you believe that all canines evolved from earlier canine variants, horses, zebras etc. evolved from earlier equine variants, alligaors, crocodiles, gavials etc. evolved from earlier crocodilian variants.

Extending this argument to it's logical conclusion, you end up with intelligent design and dinosaurs sharing the planet with apes. This occurs because simple precellular life cannot evolve into single cell life, single cell life evolve into simple multicellular life, simple multicellular life into complex multicellular life, different lineages of multicellular life branching into multiple unique and seemingly unrelated life.

In short your theory requires that the primordial earth be populated by "advanced" life forms that were spontaneously created. Note this is not intelligent design, but simply "Spontaneous Creation" of "higher" life forms directly out of the chemical broth that covered the early Earth.

These various lineages then had to survive ALL the disasters and climate changes that have occurred during the subsequent history of the Earth.

Applying Occam's Razor to the logical consequences of your theory lends credence to evolution generating what appear to be major leaps in form and function.

This article documents the discovery of physical evidence of one of the gradual changes that your theory requires, so I do not understand why you are objecting to an interpretation of the discovery that lends support to your beliefs.

RE: Why Bother?
By PaterPelligrino on 4/20/2011 12:26:17 PM , Rating: 1
I'm not religious and I DO believe in Evolution.

However I do not believe in this kind of macro-evolutionist crap. Sorry but lizards don't eventually become men through a long series of changes

Forgive me if I doubt your assertion that you are not religious, that you reject macro-evolution simply because it doesn't make sense to you. In my experience, those who reject evolution are almost always biblical literalists - though, for obvious reasons, some are reluctant to admit it in online discussions about evolution. However, the biblical literalist doesn't reject evolution because he disagrees with the science, he rejects it out of hand to safeguard his religious beliefs.

But let's take your statement at face value. So if you are not religious - which means you do not accept the creationist explanation for the existence of life - how do you explain the existence of all the distinct species that have ever existed on earth?

If life hasn't divine origins, there must be a scientific explanation for how it arose. What possible non-divine explanation could account for the existence of so many different species that doesn't involve evolution from a common origin? Many creatures alive today clearly weren't here in the remote past; where did they come from? Did the horse and Homo Sap just one day pop into existence without any precedents?

I'm not aware of a competing non-religious explanation for the origin of species, so I'm looking forward to your reply.

RE: Why Bother?
By Suntan on 4/19/2011 3:52:50 PM , Rating: 2
I find it funny how people complain about research into evolution and the news coverage thereof, when often in the same breath they go on to complain about the supposed "lack of evidence" (fossils, etc.) supporting evolution.

I find it funny that you are suggesting I’m doing that by even writing this as a response.

My issue isn’t with evolution. My issue is with Dailytech half-heartedly cutting/pasting someone else’s article about a specific topic of evolution in an effort to get people here to argue about it.

Feel free to spin that buster…


RE: Why Bother?
By JasonMick on 4/19/2011 4:45:50 PM , Rating: 2
Feel free to spin that buster…

LOOK. I'm not trying to spin your remark. I'm just pointing out that a large number of DailyTech commenters (perhaps not yourself) complain about us covering the topic of evolution. A frequent argument is that there is a lack of evidence.

So when we present a prestigious scientific study on some of the evidence, it hardly seems fair to be accused of flamebating. We're just offering that evidence people are always demanding.

My issue isn’t with evolution. My issue is with Dailytech half-heartedly cutting/pasting someone else’s article about a specific topic of evolution in an effort to get people here to argue about it.

I fail to see how Tiffany used "cutting/pasting" to write this piece, other than direct quotes. What would you suggest, she went out and did the study herself?

Can you give any meaningful evidence to support your outlandish and inflammatory claims? Or are you content just to sit behind your keyboard and try to play bully with one of our hardest working writers?

Honestly, I don't think there's any pleasing you.

Tiffany wrote a terrific, well-researched piece on a study published in science's most prestigious journal.

But for some reason that's not up to your standards.

I don't know what to tell you...

"And boy have we patented it!" -- Steve Jobs, Macworld 2007

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