VOA科学技术2024--Creature Offers Clues on Amphibian Evolution

Creature Offers Clues on Amphibian¹ Evolution

　　Scientists recently studied the fossil of a creature that lived in what is now the U.S. state of Texas about 270 million years ago. They named it Kermitops gratus in honor of Kermit the Frog from the children's television program The Muppets.

　　The fossil belongs to a group of animals that are thought to have given rise to modern-day frogs, salamanders, and limbless caecilians. Those animals, called amphibians², are creatures that can live both on land and in water.

　　And the study offers details into the history of how amphibians have evolved.

　　Only the head, or skull³, was discovered. It measured around three centimeters long. Researchers think the amphibian-like creature had a wide body that was around 15-18 centimeters long.

　　Amphibians are one of the four groups of living vertebrates on land. The others are reptiles⁴, birds, and mammals. Special details, or features, on the Kermitops skull are providing researchers with more information about the history of amphibians.

　　Calvin So is a George Washington University doctoral student. And he is the lead writer of the study recently released in the publication Zoological Journal of the Linnean Society.

　　So said Kermitops helps researchers understand the early history of amphibians by showing there is not a clear history "of step by step becoming more like the modern amphibian."

　　The fossil was collected in 1984 near Lake Kemp in Texas. It was kept in the large collection of the Smithsonian Institution's National Museum of Natural History in Washington, D.C. But it was not fully⁵ studied until recently.

　　Kermitops had facial features that were similar to frogs and salamanders. But it had palpebral bones or eyelid⁶ bones, that are not found in modern amphibians.

　　So said, "The length of the skull in front of the eyes is longer than the length of the skull behind the eyes, which differs from the other fossil amphibians living at the same time." He added that it might have enabled Kermitops to close its mouth faster than others to capture insects as food.

　　So added, "We really thought it looked like Kermit the Frog." That led researchers to name it Kermitops, meaning "Kermit face."

　　Kermitops lived about 20 million years before the worst mass die-off, or extinction⁷, in Earth's history. And it appeared about 40 million years before the first dinosaurs⁸. It lived alongside other members that formed the amphibian group.

　　The environment in which Kermitops lived appears to have changed back and forth⁹ between warm and wet seasons and hot and dry seasons.

　　So said, "This environment would be similar to modern-day monsoons¹¹ that take place in the Southwest U.S. and Southeast Asia."

　　The fossil record of early amphibians and their ancestors is not complete. That makes it difficult to understand the beginnings of modern amphibians.

　　Arjan Mann of the National Museum of Natural History helped write the study. He said Kermitops shows the importance "of continuing to add new fossil data to understanding this evolutionary¹² problem."

　　Words in This Story

　　fossil – n. something (such as a leaf, skeleton, or footprint) that is from a plant or animal which lived in ancient times and that you can see in some rocks

　　amphibian – n. an animal (such as a frog or toad) that can live both on land and in water

　　evolution – n. the process by which changes in plants and animals happen over time

　　vertebrate – n. an animal that has a backbone¹³

　　monsoon¹⁰ – n. a wind in the Indian Ocean and southern Asia that brings heavy rains in the summer

1 amphibian   

n.两栖动物；水陆两用飞机和车辆

参考例句：

• The frog is an amphibian,which means it can live on land and in water.青蛙属于两栖动物，也就是说它既能生活在陆地上也能生活在水里。
• Amphibian is an important specie in ecosystem and has profound meaning in the ecotoxicology evaluation.两栖类是生态系统中的重要物种，并且对环境毒理评价有着深远意义。

2 amphibians   

两栖动物( amphibian的名词复数 )； 水陆两用车； 水旱两生植物； 水陆两用飞行器

参考例句：

• The skin of amphibians is permeable to water. 两栖动物的皮肤是透水的。
• Two amphibians ferry them out over the sands. 两辆水陆两用车把他们渡过沙滩。

3 skull   

n.头骨；颅骨

参考例句：

• The skull bones fuse between the ages of fifteen and twenty-five.头骨在15至25岁之间长合。
• He fell out of the window and cracked his skull.他从窗子摔了出去，跌裂了颅骨。

4 reptiles   

n.爬行动物，爬虫( reptile的名词复数 )

参考例句：

• Snakes and crocodiles are both reptiles. 蛇和鳄鱼都是爬行动物。 来自《简明英汉词典》
• Birds, reptiles and insects come from eggs. 鸟类、爬虫及昆虫是卵生的。 来自《现代汉英综合大词典》

5 fully   

adv.完全地，全部地，彻底地；充分地

参考例句：

• The doctor asked me to breathe in,then to breathe out fully.医生让我先吸气，然后全部呼出。
• They soon became fully integrated into the local community.他们很快就完全融入了当地人的圈子。

6 eyelid   

n.眼睑，眼皮

参考例句：

• She lifted one eyelid to see what he was doing.她抬起一只眼皮看看他在做什么。
• My eyelid has been tumid since yesterday.从昨天起，我的眼皮就肿了。

7 extinction   

n.熄灭，消亡，消灭，灭绝，绝种

参考例句：

• The plant is now in danger of extinction.这种植物现在有绝种的危险。
• The island's way of life is doomed to extinction.这个岛上的生活方式注定要消失。

8 dinosaurs   

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》

9 forth   

adv.向前；向外，往外

参考例句：

• The wind moved the trees gently back and forth.风吹得树轻轻地来回摇晃。
• He gave forth a series of works in rapid succession.他很快连续发表了一系列的作品。

10 monsoon   

n.季雨，季风，大雨

参考例句：

• The monsoon rains started early this year.今年季雨降雨开始得早。
• The main climate type in that region is monsoon.那个地区主要以季风气候为主要气候类型。

11 monsoons   

n.（南亚、尤指印度洋的）季风( monsoon的名词复数 )；（与季风相伴的）雨季；（南亚地区的）雨季

参考例句：

• In Ban-gladesh, the monsoons have started. 在孟加拉，雨季已经开始了。 来自辞典例句
• The coastline significantly influences the monsoons in two other respects. 海岸线在另外两个方面大大地影响季风。 来自辞典例句

12 evolutionary   

adj.进化的；演化的，演变的；[生]进化论的

参考例句：

• Life has its own evolutionary process.生命有其自身的进化过程。
• These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。

13 backbone   

n.脊骨，脊柱，骨干；刚毅，骨气

参考例句：

• The Chinese people have backbone.中国人民有骨气。
• The backbone is an articulate structure.脊椎骨是一种关节相连的结构。