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A newly discovered frog fossil represents the oldest tadpole ever found, and it looks remarkably like the tadpoles you're probably familiar with except for one thing -- it was a giant.
一个新发现的蛙类化石，是到目前为止所找到的最古老的蝌蚪，而且看起来跟你可能很熟悉的蝌蚪很像，只有一件事例外--它个头超大。
Paleontologist Federico Agnolín and his colleagues discovered the fossil by accident.
古生物学家费德里格·安诺林和同事找到这个化石完全是意外。
The team had been scouring the same quarry at Estancia La Matilde in the Santa Cruz province of Argentina for dinosaurs.
他们的团队已经在阿根廷圣克鲁斯省的拉尔玛蒂达庄园的一个采石场搜寻了许久。
They hoped that the fine sediment and volcanic ash that formed the quarry's Jurassic-period rock may have preserved the imprint of soft tissues never discovered before.
形成这片采石场侏罗纪岩石的是细致的沉积物和火山灰，他们原本希望里面能留下以前从未发现过的软组织印痕。
Yet instead of dinos, they kept finding frogs.
然而，他们发现的不是恐龙，而是青蛙。
The frogs were all adults from the same extinct species, Notobatrachus degiustoi.
这些蛙都是同一个已灭绝蛙类Notobatrachus degiustoi的成蛙。
That led some researchers to speculate that perhaps in those days, frogs didn't have a tadpole stage yet.
这也让某些研究人员开始怀疑，或许那个年代的蛙类是不会经过蝌蚪阶段的。
Yet in January 2020, a team member picked up a rock during a break and found a more than six inches long imprint of a tadpole revealing exquisite details of its gills, eyes, and even some nerves.
但在2020年1月，一名团队成员在休息时段捡起了一块石头，结果发现了一个超过6英寸长的蝌蚪印痕，上面的细节非常细致，包括鳃、双眼，甚至还有一些神经。
The researchers who described the fossil in Nature today estimate it to be between 161 to 168 million years old, beating the previous record holder by around 30 million years.
在10月30日的《自然》期刊上描述了这块化石的研究人员估计，这块化石约有1亿6100万年到1亿6800万年的历史，比之前的纪录保持化石还老了大约3000万年。
The find provides solid evidence frogs have had a tadpole stage for at least that long.
这项发现提供了确凿的证据，证实蛙类有蝌蚪阶段至少已经有那么久了。
"It's a beautiful confirmation of what many experts had suspected," says herpetologist Alexander Haas of the Leibniz Institute in Bonn, Germany.
“这完美地证实了许多专家怀疑的事情。”德国波昂布莱尼兹研究所的爬虫学家亚历山大·哈斯说。
Reconstructing tadpole evolution based on their diversity today, Haas and others previously predicted that tadpoles would have existed this early on.
哈斯目前正根据蝌蚪的多样性重建它们的进化过程，他之前就曾和其他学者预测，在那么早的年代已经有蝌蚪的存在了。
Since he wasn't an expert in frogs himself, Agnolín sought help from biologist Mariana Chuliver, who like him is based at the Fundación Félix de Azara in Buenos Aires, Argentina, and had studied tadpole development in frogs before.
因为本身不是蛙类专家，所以安诺林去寻求生物学家玛丽安娜·楚利维的协助，他们一样都是在阿根廷布宜诺斯艾利斯的菲利克斯·德阿扎拉基金会工作，但楚利维之前就研究过蛙类的蝌蚪发育。
When looking at the fossil under the microscope, she found the cartilage supporting its gills to be surprisingly similar to that of tadpoles alive today.
在显微镜下检视该化石的时候，她发现支撑着鳃的软骨组织跟现存的蝌蚪惊人地相似。
Like its present-day brethren, tadpoles of this extinct species would have sucked in water and then pushed it out across their gills, filtering out food and absorbing oxygen all in one go.
这个已灭物种的蝌蚪，就和现在的同类蝌蚪一样，是把水吸进来之后再经过鳃往外挤出去，过滤食物和吸收氧气同时搞定。
This suggests it probably wasn't feeding on the small shellfish, insects and crustaceans also found as fossils in these rocks, but rather on micro-organisms and organic debris floating in the water, says Chuliver.
楚利维称，这表明它吃的可能不是同样在这些岩石中发现的小型贝类、昆虫和甲壳类，而是微生物和水中漂浮的有机碎屑。
