大型爬行动物曾与哺乳动物共生于地球

海量资料下载 免费学习英语 www.englishvip.com/xinlw.htm （申请网址） Some 40 million years before rock singer Jim Morrison's lyrics earned him the moniker（绰号，名字） "the Lizard King," an actual king lizard roamed the hot tropical forests of Southeast Asia, competing with mammals for food and other resources. A team of U.S. paleontologists, led by Jason Head of the University of Nebraska-Lincoln, describes fossils of the giant lizard from Myanmar this week in the scientific journal Proceedings of the Royal Society B. Their analysis shows that it is one of the biggest known lizards ever to have lived on land.   The creature's scientific name is Barbaturex morrisoni -- which means "Lizard King," in honor of the aforementioned（上述的） Doors singer.   At almost six feet long and weighing upwards of 60 pounds, the lizard provides new and important clues on the evolution of plant-eating reptiles and their relationship to global climate and competition with mammals.   In today's world, plant-eating lizards like iguanas（鬃蜥） and agamids are much smaller than large mammal herbivores（食草动物）. The largest lizards, like the giant, carnivorous Komodo dragon, are limited to islands that are light on mammal predators. It is not known, however, if lizards are limited in size by competition with mammals, or by temperatures of modern climates, Head said.   But B. morrisoni lived in an ecosystem with a diversity of both herbivorous and carnivorous mammals during a warm age in Earth's history -- 36 to 40 million years ago -- when there was no ice at the poles and atmospheric carbon dioxide levels were very high. The creature was larger than most of the mammals with which it lived, suggesting that competition or predation by mammals did not restrict its evolution into a giant.   "We think the warm climate during that period of time allowed the evolution of a large body size and the ability of plant-eating lizards to successfully compete in mammal faunas," Head said.   "You can't fully understand the evolution of ecosystems in the modern world without looking at the ones that preceded them. We would've never known this by looking at lizards today. By going back in time using the fossil record, we can find unique information on the origin of modern ecosystems."   Head worked with Patricia Holroyd of University of California, Berkeley, Gregg Gunnell of Duke University, and Russell Ciochon of the University of Iowa on identifying and analyzing B. morrisoni. 大约40亿年前的摇滚歌手吉姆·莫里森的歌词赢得了他的绰号（绰号，名字） “蜥蜴王”，实际王蜥蜴漫游东南亚炎热的热带雨林，与哺乳动物食物和其他资源竞争。由Jason头内布拉斯加-林肯大学，美国古生物学家，带领一队这个星期在科学期刊论文的皇家学会学报B描述了来自缅甸的巨型蜥蜴化石他们的分析明，它是一个已知的最大蜥蜴以往任何时候都生活在陆地上。   生物的的学名是Barbaturex morrisoni -这意味着“蜥蜴王”，在上述（上述的）门歌手的荣誉。   在近六英尺长，重达60磅以上，蜥蜴草食爬行动物和他们的关系，全球气候变化和与哺乳动物的竞争演变提供了新的重要线索。   在今天的世界，厂房吃鬣蜥等蜥蜴（鬃蜥）和agamids的大型哺乳动物食草动物（食草动物）相比要小得多。最大的蜥蜴，像巨人，食肉科莫多龙，是有限的岛屿是光对哺乳动物天敌。然而，它不知道，如果蜥蜴的大小受限制的竞争与哺乳动物，或通过现代气候条件下的温度，总目。   但morrisoni B.食草和食肉哺乳动物的多样性，在一个温暖的年龄 - 36至40万年前在地球的历史上生活在一个生态系统 - 当没有在两极冰和大气中的二氧化碳水平非常高。生物是大于与它居住的大多数哺乳动物，这表明竞争或捕食哺乳动物并没有限制其演变成一个巨大的。   “我们认为，在那段时间让温暖的气候演变的大车身尺寸和植物为食的蜥蜴成功地在哺乳动物动物群竞争的能力，”赫德说。   “你不能完全理解生态系统的演变在现代世界的不看那些他们之前，我们从来不知道今天看着蜥蜴，时光倒流使用化石记录，我们可以发现独特的信息现代化的生态系统的起源。“   主管的工作与帕特里夏·霍洛伊德加州大学伯克利分校，杜克大学的格雷格甘内尔，美国爱荷华大学的罗素乔昆识别和分析B. morrisoni的。 “成千上万人疯狂下载。。。。。。 更多价值连城的绝密英语学习资料， 洛基内部秘密英语，技巧，策略 请在 网上 申请报名” 洛基国际英语 竭诚为您服务