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標題: 發現最早壁虎藏於一億年前琥珀內  
 
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發現最早壁虎藏於一億年前琥珀內


保存在琥珀中1億年的壁虎化石腳趾清晰可見




保存在琥珀中1億年的壁虎化石腳趾清晰可見

    據美國科學日報報道,日前,美國俄勒岡州大學和英國倫敦自然歷史博物館的科學家們宣稱,在緬甸發現世界上最古老的壁虎化石,壁虎的身體被完好地保存在1億年前的琥珀之中,至今仍保留著十分逼真的模樣。

    由于琥珀具有顯著的防腐保存性能,這只遠古壁虎腳上仍清晰可見微小的“絨毛”,這種帶有粘性的腳趾絨毛使現代壁虎具有非同尋常的攀爬能力,它們毫不費力地爬行于天花板的表面上。全球范圍內的研究計劃試著模擬壁虎這種怪異的粘性攀爬能力,但是相應的成功研究卻為數不多。

    遠古時期的壁虎化石標本十分難得,考古學家有時會在遠古化石樣本中發現殘留在石頭上的壁虎腳趾、尾部,但是保存完好的屍體卻很少見。畢竟在0.97-1.1億年前的白堊紀下層時期,緬甸熱帶雨林地區小型恐龍和其他掠食性動物是不會放過壁虎這種美味食物的。這項發現比之前人類所發現的最古老壁虎化石至少要提前0.4億年,進而揭示了遠古壁虎進化歷史——遠古時期它們奔跑于體型龐大的恐龍腳下,現今的壁虎物種仍保留著與遠古壁虎生活在熱帶和亞熱帶地區的共同特性。目前,這項研究報告發表在近期出版的《動物學分類》(Zootaxa)雜志上。

    俄勒岡大學喬治·波奈爾教授說,“一些壁虎物種不同尋常的腳趾墊和攀爬能力,使它們成為具有魅力的一種動物,我們能夠幸運地發現保存如此完好化石標本的微小足部。由于壁虎是一種具有特殊能力的物種,對于這個最古老壁虎化石的發現,使科學家們非常地興奮欣喜!”據悉,他是當今世界上琥珀中包裹昆蟲、植物等遠古生命研究的頂尖專家,琥珀是一種半寶石形式的化石,最初是由古代樹液形成的。

    基于對壁虎腳趾上發現的絨毛數量,研究人員分析琥珀中保存的這個壁虎相對成年體而言只是一只年輕的小壁虎,這種遠古壁虎成年體長可能達到1英尺。現代壁虎的體長不會超過16英寸,雖然數百萬年前遠古壁虎的體型要更大一些,目前保存在琥珀中的這只小壁虎體長只有不足1英寸,在它死亡時,很可能被掠食者吃了一半或者遭受攻擊,只有部分身體完好地保存在琥珀中。研究人員宣稱這項發現證實了一種遠古壁虎新物種的存在,目前它已滅絕消失,並對它取名為“白堊紀壁虎”,它身體上的斑紋很可能是起到偽裝保護作用。

    現今世界上壁虎物種已超過1200多種,一般生存于溫暖的熱帶地區,其中包括美國南部部分地區。目前壁虎經常被人們當作寵物一樣飼養,由于它們能夠吃昆蟲,因而頗受熱帶地區居民家庭的青睞。一些壁虎物種的身體顏色十分鮮艷美麗,它們會使用長舌頭舔自己的眼睛,使眼睛保持清潔和濕潤。

    波奈爾說,“壁虎的領土捍衛能力很強,在1980年代初我在非洲生活時,我就非常喜歡在自己家中飼養壁虎。它們非常友善,並不會打擾人類的生活。它們會在房子裏幫助我殺死蚊子,控制害蟲的數量。同時,它們會爬在天花板上,用眼睛盯著你看。”這項最新研究證實了這種生活在亞洲緬甸的遠古壁虎的歷史可追溯到1億年前,那時壁虎已進化形成奇特的足部結構。這塊琥珀挖掘發現于緬甸葫坎谷(Hukawng Valley),其存活時很可能生活在一個潮濕的熱帶雨林中,該雨林環境中對壁虎提供了許多攀登的機會。

    壁虎能夠在垂直表面上行走的能力源于其腳趾上有數以千計的“剛毛”,這種毛發結構通過范德華力(van der Walls)緊緊地粘附在表面上。這是其他物種所不具備的強勁、幹燥的吸附粘合能力。研究人員尚不清楚壁虎究竟是在遠古什麼時期開始具備這種特殊粘附能力,以及什麼時期進化形成它們的粘性腳趾。然而,這項最新研究很清晰地顯示壁虎具有該能力至少已有1億年,至今現代研究項目仍無法完全復制壁虎的這種能力。

    加州大學伯克利分校的科學家們聲稱,今年初,他們成功研制一種新型“防滑”粘合劑。表示這是模擬壁虎能力最成功的一種人造材料,他們認為這將有助于機器人攀爬在墻壁上。今年,美國麻省理工學院的一支研究小組受壁虎的靈感啟發,成功研制出一種防水粘性繃帶,有朝一日能夠用于手術室治療。




2008-8-28 12:39 AM#1
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OSU scientists discover oldest known gecko fossil
Scientists from Oregon State University and the Natural History Museum in London have announced the discovery of the oldest known fossil of a gecko, with body parts that are forever preserved in life-like form after 100 million years of being entombed in amber.






Due to the remarkable preservative power of being embalmed in amber, the tiny foot of this ancient lizard still shows the tiny “lamellae,” or sticky toe hairs, that to this day give modern geckos their unusual ability to cling to surfaces or run across a ceiling. Research programs around the world have tried to mimic this bizarre adhesive capability, with limited success.

This gecko’s running days are over, however, as only the foot, toes and part of a tail are left in the stone. The rest might have become lunch for a small dinosaur or other predator during an ancient fight in the tropical forests of Myanmar during the Lower Cretaceous Period, from 97 million to 110 million years ago.

The find is at least 40 million years older than the oldest known gecko fossil, shedding additional light on the evolution and history of these ancient lizards that scampered among the feet of giant dinosaurs then and still are common in tropical or sub-tropical regions all over the world.

The findings were just published in Zootaxa, a professional journal.

“It’s the unusual toe pads and clinging ability of some geckos that make them such a fascinating group of animals, so we were very fortunate to find such a well-preserved foot in this fossil specimen,” said George Poinar, Jr., a courtesy professor at OSU and one of the world’s leading experts on insects, plants and other life forms trapped in amber, a semi-precious stone that begins as tree sap.

“There’s a gecko society, gecko clubs, just a lot of interest in these animals because of their unusual characteristics,” Poinar said. “So there are a lot of people pretty excited about this.”




Based on the number of lamellae found on its toe pads, this gecko was probably a very small juvenile of what would have become a comparatively large adult, possibly up to a foot long, the researchers say. Modern geckos get no more than about 16 inches long, although it’s possible there were larger species millions of years ago. The juvenile gecko found in the fossil was less than an inch in length when it died – possibly by being eaten or attacked, since only partial remains were found.

The discovery has been announced as a new genus and species of gecko, now extinct, and has been named Cretaceogekko. It had a striped pattern that probably served as camouflage.






There are more than 1,200 species of geckos in the world today, common in warm or tropical regions, including parts of the southern United States. They are frequently kept as pets, and often are welcome in the homes of some tropical residents because they help control insects. Some are very colorful. They use long tongues to lick, clean and moisturize their eyes.

“Geckos are territorial, and when I lived in Africa in the early 1980s we used to have them in our house,” Poinar said. “They are pretty friendly and don’t bother humans. Certain individuals would move into the house, we’d give them names, and they would run around the house, catch mosquitoes, help control bugs. They would crawl across the ceiling and look down at you.”

The new study provides evidence that geckos were definitely in Asia by 100 million years ago, and had already evolved their bizarre foot structure at that time. The amber fossil was mined in the Hukawng Valley in Myanmar, and during its life the gecko probably lived in a moist, tropical forest with ample opportunities for climbing.

The ability of geckos to walk on vertical walls or even upside down is due to the presence of thousands of “setae” on their toes, very tiny, hairlike structures that have tips which attach to surfaces by van der Walls forces. It’s a type of incredibly strong, dry adhesion shared by virtually no other group of animals.

It’s not known exactly how old this group of animals is, and when they evolved their adhesive toe pads. However, the new study makes it clear that this ability was in place at least 100 million years ago, in nature. Modern research programs still have not been able to completely duplicate it.

Scientists at the University of California at Berkeley reported earlier this year that they have developed a new “anti-sliding” adhesive that they said was the closest man-made material yet to mimic the ability of geckos – they think it might help a robot climb up the side of walls.  A research team at the Massachusetts Institute of Technology this year created a waterproof adhesive bandage inspired by geckos, that may some day be used in surgery. And of course, geckos have become an advertising icon for the insurance company Geico.

This study is just one of many in which Poinar and colleagues have used the unusual characteristics of amber to study ancient life forms and develop information on the ecology of ancient ecosystems.

As a stone that first begins to form as sap oozing from a tree, amber can trap small insects or other life forms and preserve them in near-perfect detail for observation millions of years later.




2008-8-28 12:42 AM#2
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Franco仔 (震旦紀)
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太棒了,一定so expersive了~~~



我愛活化石!
2008-8-28 01:05 PM#3
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好棒呀!!
2008-8-28 02:19 PM#4
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2008-9-2 06:03 PM#5
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有翻譯了



2008-9-6 06:55 AM#6
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尾羽龙
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连壁虎都有,不可思议啊
2008-9-16 02:41 PM#7
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唔影埋個body或頭既....
2008-12-14 12:24 AM#8
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fossilshk (Lung)
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回復 #8 leo2004 的帖子

找不到圖片



2008-12-17 02:24 AM#9
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39611128 (銀鍠黥武)
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琥珀裡真是無奇不有...真想看看琥珀裡有沒有蟑螂
2008-12-28 09:36 PM#10
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