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VOA科学技术2024--Researchers Discover World's Oldest Tadpole

时间：2025-01-09 02:07:46

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Scientists in Argentina have discovered the oldest-known remains1 of the tadpole2. The animal belonged to a large frog species that lived alongside dinosaurs4 about 161 million years ago.

The researchers said the 16-centimeter-long tadpole died during the larval period, or stage, of frog development. The discovery is providing new information about the development of frogs and toads5.

The remains suggest tadpoles6 today are largely unchanged from their ancestors in the ancient time called the Jurassic period. The oldest-known frog remains date back even further, though no older tadpole fossils have been found.

The remains are in good condition. In fact, researchers say, the ancient tadpole has some soft tissues rarely seen in fossils. The tadpole's eyes and nerves, for example, appear as dark markings in the fossil.

Fossil hunters found the tadpole in 2020, during a dig for dinosaur3 remains on a ranch7 in the southern province of Santa Cruz. The fossil includes the tadpole's head and most of its body.

Frogs have a two-stage life cycle, with the tadpole larva developing into the adult form. This tadpole was in the late stages of development. Adults of this species are a similar length as the tadpole, the researchers said.

"It's not only the oldest tadpole in the world and amazingly preserved, but it also tells us about the size of one of the few frog species known from that time," said biologist Mariana Chuliver of Fundación Azara-Universidad Maimónides.

Chuliver was the lead writer of the study that appeared recently in the scientific publication Nature.

Chuliver said the soft tissue remains are important because they permit researchers to "know the diet and lifestyle of these organisms."

The remains, Chuliver added, show that the form and structure of tadpoles have "remained almost unchanged over the last 160 million years."

I'm John Russell.

Miguel Lo Bianco reported on this story for Reuters. John Russell adapted it for VOA Learning English.

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Words in This Story

species - n. a class of animals having common attributes and designated by a common name

fossil - n. the remains of an organism of past geologic8 ages that has been preserved in the earth's crust

preserve - v. to keep intact or free from decay


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1 remains 1kMzTy     
n.剩余物，残留物；遗体，遗迹
参考例句：
  • He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
  • The remains of the meal were fed to the dog.残羹剩饭喂狗了。
2 tadpole GIvzw     
n.[动]蝌蚪
参考例句：
  • As a tadpole changes into a frog,its tail is gradually absorbed.蝌蚪变成蛙，它的尾巴就逐渐被吸收掉。
  • It was a tadpole.Now it is a frog.它过去是蝌蚪，现在是一只青蛙。
3 dinosaur xuSxp     
n.恐龙
参考例句：
  • Are you trying to tell me that David was attacked by a dinosaur?你是想要告诉我大卫被一支恐龙所攻击？
  • He stared at the faithful miniature of the dinosaur.他凝视著精确的恐龙缩小模型。
4 dinosaurs 87f9c39b9e3f358174d58a584c2727b4     
n.恐龙( dinosaur的名词复数 )；守旧落伍的人，过时落后的东西
参考例句：
  • The brontosaurus was one of the largest of all dinosaurs. 雷龙是所有恐龙中最大的一种。 来自《简明英汉词典》
  • Dinosaurs have been extinct for millions of years. 恐龙绝种已有几百万年了。 来自《简明英汉词典》
5 toads 848d4ebf1875eac88fe0765c59ce57d1     
n.蟾蜍，癞蛤蟆( toad的名词复数 )
参考例句：
  • All toads blink when they swallow. 所有的癞蛤蟆吞食东西时都会眨眼皮。 来自《简明英汉词典》
  • Toads have shorter legs and are generally more clumsy than frogs. 蟾蜍比青蛙脚短，一般说来没有青蛙灵活。 来自辞典例句
6 tadpoles 1abae2c527b80ebae05cd93670639707     
n.蝌蚪( tadpole的名词复数 )
参考例句：
  • The pond teemed with tadpoles. 池子里有很多蝌蚪。 来自《简明英汉词典》
  • Both fish and tadpoles have gills. 鱼和蝌蚪都有鳃。 来自《现代汉英综合大词典》
7 ranch dAUzk     
n.大牧场，大农场
参考例句：
  • He went to work on a ranch.他去一个大农场干活。
  • The ranch is in the middle of a large plateau.该牧场位于一个辽阔高原的中部。
8 geologic dg3x9     
adj.地质的
参考例句：
  • The Red Sea is a geologic continuation of the valley.红海就是一个峡谷在地质上的继续发展。
  • Delineation of channels is the first step of geologic evaluation.勾划河道的轮廓是地质解译的第一步。

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