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人 類 和 現 代 大 型 猿 類 動 物 在 進 化 史 上 最 後 一 個 共 同 祖 先
( 星 島 日 報 報 道 ) 人 類 和 現 代 大 型 猿 類 動 物 在 進 化 史 上 最 後 一 個 共 同 祖 先 ， 可 能 就 是 西 班 牙 東 北 部 最 近 出 土 的 化 石 主 人 ─ ─ 爬 樹 類 動 物 。
西 班 牙 米 格 爾 ． 克 魯 薩 方 特 古 生 物 學 研 究 院 專 家 索 拉 所 率 領 的 探 挖 小 組 ， 在 巴 塞 隆 那 郊 外 二 十 里 的 一 個 「 小 盆 地 」 ， 發 現 了 八 十 三 件 來 自 同 一 種 動 物 的 骸 骨 化 石 ， 年 代 可 以 追 溯 到 一 千 三 百 萬 年 前 。
這 批 化 石 分 別 屬 於 頭 蓋 骨 、 椎 骨 、 腕 骨 和 身 體 其 他 部 位 的 骨 頭 。 經 過 拼 湊 後 ， 科 學 家 發 現 ， 化 石 主 人 屬 於 雄 性 ， 有
Fossil find may be the father of us all
It\’s hailed as last common kin of the great apes and humansDavid Perlman, Chronicle Science Editor
Monday, November 22, 2004
Spanish anthropologists, intrigued by a single fossil tooth found near a Catalonian village, dug up more of the animal\’s stony skeleton and announced they have discovered what may be the last common ancestor of all the world\’s living great apes — including the human family.
And unlike theories on the evolution of human running that provoked strong controversy last week, the find is being heralded as highly significant and filled with fresh insights into the long and murky quest for understanding how Homo sapiens came to be.
The Spanish scientists are calling their new ape species Pierolapithecus catalaunicus and say that it must have lived nearly 13 million years ago, during a period known geologically as the Middle Miocene — a time for which the fossil evidence of animal life has been extremely scarce until now.
The ancient ape or its close relatives, the scientists believe, would have been the ancestor of today\’s chimpanzees, gorillas, orangutans and, of course, humans. The entire great ape lineage was separated millions of years earlier from the lesser apes like gibbons and siamangs, as well as by the monkeys of both the New World and the Old, they say.
The leader of the anthropology team is Salvador Moya-Sola of Barcelona\’s Paleontology Institute, and his group\’s report was published Friday in the journal Science.
During a telephone press conference from Spain, Meike Kohler, one of the scientists, said she pictures their ancient ape\’s features as \”a kind of bridge between something more primitive and something more advanced — not a missing link, but a basic body design leading to modern apes and humans.\”
\”This is really an exciting discovery,\” C. Owen Lovejoy of Kent State University in Ohio, a veteran expert on primate fossils and human evolution who is familiar with the work but not connected to the group, said in an interview. \”It is filling in what until now has seen only the most meager evidence for the idea, but now the fossil evidence seems strong.\”
The extraordinary find comes from a new and rich fossil site, near the village of Hostalets de Pierola, and it \”promises to contribute substantially to our understanding of the origin of extant great apes and humans,\” Moya-Sola said.
The name Pierolapithecus for the fossil bones of the primitive ape combines part of the village\’s name with the Greek word for ape, while catalaunicus derives from Catalonia, the province where both the village and Barcelona are located.
The trove of bones the scientists uncovered there included all or parts of the skull, the metacarpal bones of both hands and feet, pieces of toes and fingers, three vertebrae, two complete ribs and large fragments of a dozen others.
From those 83 fossils, Moya-Sola and his colleagues deduced they had found the bones of what was most probably a single adult male that weighed about 75 pounds, and was well adapted for tree climbing while upright and for knuckle-walking on the ground. And from the shape of the single surviving tooth, it was probably a fruit-eater, the scientists deduced.
Several significant features distinguish the primitive ape from the lesser apes and monkeys, the anthropologists say. For example, its rib cage, lower spine and wrist indicate it climbed the way modern great apes do; although the even more primitive monkeys also climb, their bones are very different.
The ape\’s chest, or thorax, is wider and flatter than that of monkeys, Moya-Sola said, adding: \”The thorax is the most important anatomical part of this fossil, because it is the first time that the modern ape-like thorax has been found in the fossil record.\”
In the current timetable of early primate evolution inferred by most anthropologists, the lineage of tail-bearing monkeys split off about 25 million years ago from the line that developed toward apes and humans. The gibbons and siamang lines split from the apes 14 to 16 million years ago. The great apes, with their strong upright posture, continued evolving. The orangutans split off from that line about 10 or 11 million years ago, and were followed by another split when the gorilla line branched off, leaving the ancestors of the chimpanzees.
Then about 6 to 7 million years ago came another split in the lineage, which led to the many separate branches of hominids — the Ardipithecines, the Australopithecines and eventually the genus Homo: Homo habilis, Homo erectus, and now, Homo sapiens, or us.
To Lovejoy, the Spanish scientists have struck real gold.
\”Up to now all we\’ve had is bits and scraps of evidence,\” he said. \”But this skeleton is relatively complete, and its wrist bones show one of the premier adaptations of modern great apes — a formation we call ulnar deviation. Monkeys don\’t have it, but great apes and humans do.
\”It\’s the wrist structure that a baseball pitcher can use when he throws — first twisting his right hand back and toward his right — if he\’s right- handed — and then swinging the hand forward and bending it 90 almost degrees toward his left. Monkeys can\’t do that at all.\”
Another significant difference from monkeys that makes the Spanish fossil find so significant, Lovejoy said, is the shape of the ape\’s lower back and thorax — \”it\’s a shape that lets him move through the trees by a new form of locomotion that monkeys never achieved,\” he said.
The great ape lineage, Lovejoy said, \”went through a whole host of adaptive changes over millions of years. In my view — and the Spanish fossils mark a start — the apes grew bigger and bigger, and a lot smarter.\”
http://www.sfgate.com/cgi-bin/article.cgi?file=/chronicle/archive/2004/11/22/MNGIV9VF3G1.DTL
西班牙發現1300萬年化石 疑為人類猿類共同祖先
2004/11月 20日【明報專訊】《科學》雜誌周五報道，西班牙一隊古生物學家在當地發現了一種1300萬年的物種化石，相信是人類與黑猩猩、大猩猩等當今大型猿類動物「分家」前的共同祖先，並相信那是人猿演化過程中重要的一環。
研究人員把這種新猿類物種稱為Pierolapithecus catalaunicus，牠生活於約1300萬年前，顯示牠極可能是大型類人猿最後的共同祖先。大型的「類人猿」（apes）是在1100萬至1600萬年前，由較小型的類人猿（如長臂猿）發展並分支出來，其後再發展成不同種類，當中包括猩猩（orangutans），黑猩猩（chimpanzees）、大猩猩（gorillas）及人類（humans）。
具所有現代類人猿特徵
化石雖然是在西班牙巴塞隆那市附近發現，但帶領研究的古生物學家莫洛索拉相信，牠們也曾在非洲生活﹕「這個新發現的化石重要之處，是首次有化石保留了所有現代大型類人猿的重要特徵。」
被發現的Pierolapithecus可能為雄性，模樣像黑猩猩，重約35公斤，從其牙齒狀?看，牠以水果作食物。牠的肋骨腔、下脊骨及腕關節皆顯示牠具攀爬能力，與現代大型猿人類相似。
此外，其肩胛骨生在背部，與四肢攀爬動物如狗隻及猴子生於肋骨腔旁有所不同。牠的顱骨明顯像大型猿人類，臉部相對短，鼻子上部扁平，不像猴子般雙眼之間鼻骨隆起。
但研究人員對化石是否人類與人猿之間「遺失的聯繫」持審慎態度，指它可能是從小型人猿邁向大型人猿過程中的一環，要過幾百萬年後才進化到人類真正祖先。
德通社/路透社
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