VOA科学技术2023--Sea Reptile Fossils Suggest It Was a Filter-feeder

Sea Reptile¹ Fossils Suggest It Was a Filter-feeder

Baleen² whales, such as the blue whale, are huge sea animals. Baleen describes a filter-feeding system in their mouths through which they can eat huge amounts of very small ocean animals.

But, it appears now that whales were not the first sea animals to filter-feed.

Scientists recently reported their findings from a study of ancient remains³ of a sea reptile called Hupehsuchus nanchangensis. The fossils were unearthed⁴ in China's Hubei area. The study appeared in the publication BMC Ecology and Evolution.

Hupehsuchus lived 248 million years ago, during the Triassic Period. Scientists say its fossil presents evidence of a filter-feed system similar to baleen whales.

The sea reptile lived during a time of intense biological changes following Earth's worst mass extinction⁵. Powerful volcanic⁶ bursts led to severe warming, destroying many kinds of life.

Unlike blue whales, Hupehsuchus was not large. The animal measured about one meter long, fossils show. Its mouth was narrow and toothless. It had a large tail that moved from side to side for swimming forward, and had front and back limbs to help it turn.

Its lower jaw⁷ was only loosely connected to the rest of the head bone. This permitted the animal to open its mouth widely to take in a large amount of water and the animals, zooplankton, it carried.

The baleen structure is made up of keratin, a soft organic material. The baleen traps little sea animals but lets the seawater flow out.

The researchers found evidence along the jaws⁸ suggesting the presence of soft tissues that could have served as baleen.

Paleontologist Mike Benton was a study writer.

"Altogether, this points to a soft pouch⁹ made of skin around the mouth and throat, as in modern baleen whales, and some kind of filtering device hanging from the jaws, like baleen," Benton said.

But, he added, the baleen and skin was not fossilized.

Paleontologist Long Cheng of the Wuhan Center of China Geological is the study's lead writer. He said Hupehsuchus would have continuously filter-fed at slow swimming speeds. He also said the animal would have fed in areas with a dense¹⁰ amount of zooplankton.

Long said Hupehsuchus took in water and the animals together into its mouth, "filtered out the water" and then swallowed the food.

Researchers first described Hupehsuchus fossils in the 1970s but lacked any good remains of the head. The new study involves two new fossils with well-kept head bones, or skulls¹¹.

Many sea creatures use some form of filter-feeding.

Words in This Story

filter – n. a device that is used to remove something unwanted from a liquid or gas that passes through it

extinction – n. the state or situation that results when something (such as a plant or animal species) has died out completely

limb – n. a leg or arm

paleontology – n. the science that deals with the fossils of animals and plants that lived very long ago especially in the time of dinosaurs¹²

pouch – n. a pocket of skin inside the mouths of some animals (such as squirrels and hamsters) that is used to carry food

1 reptile   

n.爬行动物；两栖动物

参考例句：

• The frog is not a true reptile.青蛙并非真正的爬行动物。
• So you should not be surprised to see someone keep a reptile as a pet.所以，你不必惊奇有人养了一只爬行动物作为宠物。

2 baleen   

n.鲸须

参考例句：

• Other baleen whales have splash guards too,but not like this.一些须鲸物种头顶也有护住喷水孔的构造，但并不长成这样。
• Baleen whales often appear in this region. Be careful!这一带经常有须鲸出没，要注意安全啊。

3 remains   

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。

4 unearthed   

出土的（考古）

参考例句：

• Many unearthed cultural relics are set forth in the exhibition hall. 展览馆里陈列着许多出土文物。
• Some utensils were in a state of decay when they were unearthed. 有些器皿在出土时已经残破。

5 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。

6 volcanic   

adj.火山的；象火山的；由火山引起的

参考例句：

• There have been several volcanic eruptions this year.今年火山爆发了好几次。
• Volcanic activity has created thermal springs and boiling mud pools.火山活动产生了温泉和沸腾的泥浆池。

7 jaw   

n.颚，颌，说教，流言蜚语；v.喋喋不休，教训

参考例句：

• He delivered a right hook to his opponent's jaw.他给了对方下巴一记右钩拳。
• A strong square jaw is a sign of firm character.强健的方下巴是刚毅性格的标志。

8 jaws   

n.口部；嘴

参考例句：

• The antelope could not escape the crocodile's gaping jaws. 那只羚羊无法从鱷鱼张开的大口中逃脱。
• The scored jaws of a vise help it bite the work. 台钳上有刻痕的虎钳牙帮助它紧咬住工件。

9 pouch   

n.小袋，小包，囊状袋；vt.装...入袋中，用袋运输；vi.用袋送信件

参考例句：

• He was going to make a tobacco pouch out of them. 他要用它们缝制一个烟草袋。
• The old man is always carrying a tobacco pouch with him.这老汉总是随身带着烟袋。

10 dense   

a.密集的，稠密的，浓密的；密度大的

参考例句：

• The general ambushed his troops in the dense woods. 将军把部队埋伏在浓密的树林里。
• The path was completely covered by the dense foliage. 小路被树叶厚厚地盖了一层。

11 skulls   

颅骨( skull的名词复数 )； 脑袋； 脑子； 脑瓜

参考例句：

• One of the women's skulls found exceeds in capacity that of the average man of today. 现已发现的女性颅骨中，其中有一个的脑容量超过了今天的普通男子。
• We could make a whole plain white with skulls in the moonlight! 我们便能令月光下的平原变白，遍布白色的骷髅！

12 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》