Scientists found a prehistoric ancestor of an arrow worm among a group of fossils at two national parks in Canada.
The fossils were found in what is now British Columbia, but was once an ocean.
The sea worm was 10 centimeters long and had 50 spines on its head. The spines could close suddenly to capture smaller sea creatures, like shrimp.
The scientists reported their discovery in the journal Current Biology in early August.
They are calling the creature Capinatator praetermissus. They say it lived 500 million years ago and is very different from anything alive now.
Capinatator means "grasping swimmer."
Derek Briggs is a scientist from Yale University. He led the expedition. He said the creature was larger than today's similar worms. The arrow worms of today have teeth instead of spines.
Briggs said the worm was probably a good predator because it had so many spines.
The scientists said it is difficult to find evidence of these prehistoric worms because their bodies decayed so quickly. But this discovery was in such good shape, they were able to make a good guess about how the worm looked.
Researchers were able to make a detailed drawing and an animation of how they think the worm moved in the ocean.
Doug Erwin works for the Smithsonian Institution in Washington, D.C. He was not involved in the research. He said the discovery will help scientists better understand the worms and other life from this ancient period.
I'm Dan Friedell.
But how do you find a fossil of a symbolic thought?
Alan grasped the handle and pulled it.
Some residents and experts said the predator may be a bear, a wayward panther or cougar, or even a wolf because 3-inch paw tracks were found at the scene.
decaying organic matter
1.They say it lived 500 million years ago and is very different from anything alive now.
be different from... 与……不同
This is different from just being tired. You actually feel yourself getting drowsy.
Test what occurs when the user "wakes it up," and the environment is different from when they suspended it.
2.The arrow worms of today have teeth instead of spines.
instead of 代替，而不是
Instead of abating, the wind is blowing even harder.
She frittered away her time in going to the cinema instead of studying.
这种生物的学名是Capinatator praetermissus。他们说，这种蠕虫生活在5亿年前，与现在存活下来的虫类非常不同 。
德里克(Derek Briggs)是耶鲁大学的科学家，也是这次研究工作的牵头者。他表示，这种蠕虫比今天类似的虫类体型都要大 。今天的箭虫有牙齿，但是没有脊刺 。
道格(Doug Erwin)是华盛顿史密斯学会的工作人员。他虽然没有参与到这次研究中，但他表示，这次的发现将助力科学家更好地理解这种虫类和其他远古时期的生物 。