琥珀中的螃蟹揭示了从海洋到陆地的演化

　　琥珀中的螃蟹揭示了从海洋到陆地的演化
　　An ancient creature found in amber may reveal a critical point in the evolutionary history of one of Earth’s most versatile animals: crabs. This 100-million-year-old fossil, discovered in Myanmar, is helping researchers resolve a prehistoric puzzle about when crabs started to move away from the seas.
　　在琥珀中发现的一种古代生物可能揭示了地球上最多才多艺的动物之一螃蟹进化史上的一个关键时刻。这块在缅甸发现的1亿年前的化石，正在帮助研究人员解决一个史前谜题:螃蟹是何时开始离开海洋的
　　Amber:琥珀
　　Versatile: 多种功能的
　　The tiny crab’s preservation is spectacular. Researchers were able to see details of the animal’s jointed legs, claws, compound eyes, and even its gills through the amber.
　　小蟹的保存是惊人的。 研究人员能够通过琥珀看到这种动物的关节腿、爪子、复眼甚至腮的细节。
　　Preservation: 保护
　　Spectacular: 令人惊叹的
　　Scientists are unsure whether the new fossil represents an adult crab or a juvenile, but the crab is so well preserved that people were able to determine that the creature is a new species.
　　科学家们尚不确定这块新化石代表的是成年螃蟹还是幼年螃蟹，但这种螃蟹保存得如此完好，以至于人们能够确定这种生物是一个新物种。
　　Juvenile: 青少年
　　Amber is fossilized tree resin, making it all the more surprising to find a crustacean encased inside. Finding a crab in amber is like finding a needle in a haystack.
　　琥珀是一种树脂化石，所以当人们发现里面有甲壳类动物时，就更加惊讶了。在琥珀里找螃蟹就像大海捞针。
　　Resin: 树脂
　　Haystack: 干草堆
　　The study team proposes that  the crab  could represent the oldest known land crab, holding clues about how crabs made the evolutionary jump from the sea to inland environments.
　　研究小组提出，这种蟹可能是已知的最古老的陆地蟹，并为蟹类如何从海洋进化到内陆环境提供了线索。
　　The condition of the amber and other clues are just as revealing as the little arthropod inside. The crab is intact, rather than an empty shell left over from molting, suggesting the animal truly did live in the habitat where it became preserved. The lack of sand grains in the amber, and the way the sap flowed over the crab, also hint that this fossil came from an environment away from the beach—likely a freshwater environment.
　　琥珀的状况和其他线索就像里面的小节肢动物一样能说明问题。这只蟹是完整的，而不是蜕皮后留下的空壳，这表明这种动物确实生活在它被保存下来的栖息地。琥珀中缺少沙粒，以及汁液流过螃蟹的方式，也暗示了这块化石来自于一个远离海滩的环境——可能是淡水环境。
　　Arthropod: 节肢动物
　　Intact:完好无缺的
　　Grain: 粒状物
　　Sap: 树的流液
　　Moving away from the ocean was a big step for crabs. Becoming adapted to life in fresh water isn’t as simple as throwing a switch. The animals had to change the way they breathed, regulated water, and kept from drying out.
　　离开海洋对螃蟹来说是一大步。要想适应淡水生活，可不是按一下开关那么简单。动物们必须改变呼吸方式，调节水分，避免干燥。
　　The largest barrier has to be how an organism manages water and electrolytes like salt in its body. Nevertheless, crabs have moved inland from the seas over and over again. Modern crabs not only live on the beach, among coral reefs, and in the ocean depths, but can also be found in rivers and lakes.
　　最大的障碍是生物体如何管理体内的水和电解质(如盐)。尽管如此，螃蟹还是一次又一次地从海洋迁移到内陆。现代的螃蟹不仅生活在海滩、珊瑚礁和海洋深处，而且在河流和湖泊中也能找到。
　　Organism: 有机体
　　Electrolyte: 电解质