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標題: 任務招領 霸王龍的牙齒 感謝  
 
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任務招領 霸王龍的牙齒 感謝

As some here might know, the T. rex specimen known as Stan has some mighty big teeth. In some instances, the maxillary (upper) teeth are so long that they project almost to the bottom of the dentary (lower jaw), which is odd. We recently got a nice cast of Stan in at the Canadian Museum of Nature (CMN) here in Ottawa and I had the chance to look at it briefly (see below). I've heard others say that the surprising length of the teeth is due to their sinking out of their sockets, which does seem somewhat waranted since the roots are visible (some people think this might be evidence that Stan had big gums. Who knows?). As my friend Margaret here at the museum pointed out, though, some of the replacement teeth can clearly be seen on the inside of the mouth, pushing against the inside of the active teeth within grooves set near the root. Because the groves aren't displaced relative to the new replacement teeth, this suggests that perhaps the large, active teeth weren't suffering from some sort of pathology/post-mortem effect. In any case, I thought I'd post this here and ask what others who might have seen the skull (or other T. rex skulls, for that matter) think of this.



Although some of the teeth in Stan's skull were loose in the matrix, and casts were put back in the sockets, we placed them as deeply as the new teeth coming in would allow. I don't think Stan is necessarily unusual. One must remember how terribly fragile these teeth are. Before Paleobond, it was very difficult to collect T. rex teeth, because they flake into hundreds of thousands of little pieces. If you look closely at most of the skulls, they have casts of teeth or carved teeth put into the sockets (and many of the teeth are just missing, or loose in the matrix). Naturally one would assume that very little of the root protruded from the gum; you would then bury the root of the tooth, leaving only the crowns exposed.

If you look at some of the more recently collected skulls of T. rex, Albertosaurus, Gorgosaurus, and Nanotyrannus, those teeth (collected with Paleobond) clearly expose a great portion of the root as well as the crown.

I think that as more specimens are collected with modern adhesives and consolidants, you'll see a lot more "snaggle-toothed" specimens.

In Stan, the only tooth that may go in a little further is actually preserved in the jaw, perhaps partially floating out of its socket. There was approximately a half-inch of space between the crown of the new tooth and the resorption cavity of the old tooth. We did not feel it was practical nor scientifically justifiable to remove the tooth and reinsert it.

Humans' interpretations and how they restore fossils is not necessarily the way the animals were in life. Preconceived notions aren't always right, and the bones don't lie.


When you mentioned the differences in Stan's teeth, it triggered a memory of mine. I have pictures of a resident Trex skull (only the skull) housed in the Museum of Natural History in Los Angeles. I also have pictures I took of Sue when she was on exhibit here in December of 2000. I went back and looked that the photos of the skull, and I realized there is quite a difference between that animal's skull and Sue's. In fact, the resident skull looks a lot like Stan's in structure. I am wondering if this animal is a subadult, or perhaps a sub species, or could this be some form of sexual difference indicating that it may have been male? I noticed that the teeth are shorter in length, and appear to be less robust (sorry, I can't send pictures, the place where I work doesn't believe in coming out of the electronic stone age, so I don't have a scanner). The museum has placed the skull at aproximately chest height (on an average sized adult human-if there is such a thing) for visual effect, so you don't notice the other differences right away. The differences became apparent when I took a picture of the skull from the side, and then only because Sue was there for comparison. This skull appears to be much shorter and deeper (but very strong looking) than Sue's skull, which also tends to make me think this was not an adult animal. Over half the teeth in the skull appear to be early replacements (is it possible they teethed like puppies), and therefore much shorter than the main teeth. While Sue's muzzle (rostrum?) is longer, it is also shallower, while the resident skull's muzzle is short and very deep. Could Sue's skull differences be caused by age or the fact that she may have been female? Would there be a way to find out if she was an old (excuse me--mature) animal, and the other one younger? If I can ever persuade someone to hook up a scanner to this computer I will send pictures so you can see what I mean! (Being technologically deprived is so frustrating) Any thoughts?
2008-1-11 11:09 PM#1
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看不明..............



鳥是恐龍!恐龍是鳥
2008-1-12 08:19 AM#2
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Franco仔 (震旦紀)
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I don't know what are you taking about???Can you speak 中文............



我愛活化石!
2008-1-12 12:34 PM#3
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Artical by yourself or copy?
2008-1-13 07:20 AM#4
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what
2008-1-20 07:53 AM#5
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nelsonkeung
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我用左lingoes翻譯,不過5是太好= =|||


正如一些這裡可能知道,暴龍標本稱為斯坦一些威武的大牙齒。在某些情況下,上頜骨(上)牙齒是如此之長,他們的項目幾乎到水底的dentary (下顎) ,這是奇怪的。我們最近得到好演員斯坦在加拿大博物館的性質( cmn )在這裡,在渥太華和我有機會看看它簡單(見下文) 。我聽說有人說,令人稱奇這麼長的牙齒,是因為他們鑿井離開自己的插座,而這似乎有點waranted自根部都是看得見(有些人認為這可能是證據表明斯坦曾大樹膠。誰知道呢? ) 。正如我的朋友吳在此間召開的博物館指出,雖然,一些更換牙齒可以清楚地看到裡面的口耳相傳,對推動內部的積極牙齒內部的凹槽,設置近治本之道。因為樹林不是流離失所相對向新更換的牙齒,這表明,也許大,中,積極牙齒沒有患上某種病理/屍體剖驗效果。在任何情況下,我以為我會發布此,並在這裡問別人曾經見過的頭骨(或其他暴龍頭骨,因為這件事)覺得這一點的。



雖然有些牙齒在斯坦的頭骨被鬆散,在矩陣,並蒙上被放回在插座,我們把他們當作深感作為新的牙齒來將允許。我不認為斯坦是一定不尋常。我們必須緊記可怕的是如何脆弱,這些牙齒。前paleobond ,這是非常困難的,以收集暴龍的牙齒,因為這些鱗片到數以十萬計的小件。如果你仔細觀察,在大部分的頭骨,他們有鑄型的牙齒或雕齒放進插座(以及很多的牙齒,只是下落不明,或鬆散,在矩陣) 。當然有人會以為很小的根源伸出從膠;你會埋葬歸根結柢的牙齒,只留下了冠暴露出來。

如果你看看一些較最近收集頭骨的暴龍,艾伯塔龍, gorgosaurus , nanotyrannus ,這些牙齒(收集與paleobond )清楚地暴露了相當大的根源,以及為冠。

我想,隨著更多的標本採集與現代粘合劑和consolidants ,你就會看到很多" snaggle齒"的標本。

在斯坦,只有牙齒可以在稍遠,其實是保存在下巴,或許部分浮出來的,其插座。有大約半英寸的空間之間的官方的新牙和resorption腔的舊牙。我們並不覺得這是現實,也不科學合理,以消除牙齒和重新它。

人類的詮釋,以及他們如何恢復化石是不一定的方式,將動物的生活情趣。先入為主的觀念並不總是正確的,骨頭不要睜眼說瞎話。


當你提到的差異斯坦的牙齒,它引發了記憶的礦井。我的照片,一名居民Trex公司頭骨(只頭骨) ,居住在自然歷史博物館在洛杉磯。我也有照片,我的控告時,她被陳列在這裡,在2000年12月。我回到了,並期待該照片的頭骨,我已意識到,有相當的區別,動物的頭骨和控告的。事實上,在駐地頭骨看起來非常類似於斯坦的結構。我在想,如果這個動物是亞成,或者一個小組的物種,或者說可以,這是某種形式的性差異,表明它可能已被男?我發覺牙齒較短長,似乎是強是弱(對不起,我不能發送圖片,地方,而我不認為在未來數列的電子石器時代的,所以我沒有掃描器) 。博物館已經把頭骨大約在胸部的高度(平均大小的成年人,如果有這樣一個東西)的視覺效果,讓你不通知其他分歧的時候了。分歧表面化後,當我合影留念的頭骨從側面,然後只是因為控告是有作比較。這個頭骨似乎是短得多和更深的(但很強烈的期待)次
2008-1-20 01:02 PM#6
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nelsonkeung
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i think he is copy from the inter net
2008-1-20 01:12 PM#7
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恐龍化身DIO (霸王龍專家)
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謝謝  不過不是很董?
2008-1-20 10:41 PM#8
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QUOTE:
原帖由 nelsonkeung 於 2008-1-20 01:02 PM 發表
我用左lingoes翻譯,不過5是太好= =|||


正如一些這裡可能知道,暴龍標本稱為斯坦一些威武的大牙齒。在某些情況下,上頜骨(上)牙齒是如此之長@...
這個就是翻譯出來的文章?




有進化的
2008-1-24 12:59 AM#9
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oviraptor (偷蛋龍)
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電腦翻譯,別有一套



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2008-1-24 03:32 PM#10
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