n. tooth form
misc. thread form
牙形石 [古生] conodont ; [古生] Conodonts
月牙形 Crescent ; [科技] lune ; Crescent-shaped
螺纹牙形 thread profile ; form of thread ; thread form ; screw-thread profile
牙形刺 [古生] conodont ; Gondolella ; Conodonts ; Icriodus de formatus
螺纹牙形角 angle of thread
牙形石类 [古生] Conodontophoridia
角牙形石属 Angulodus
变形颚牙形石属 Amorphognathus
牙形虫 Conodont
牙形刺在三叠纪末期灭绝了，这正是恐龙开始演化的时代。
Conodonts went extinct at the end of the Triassic Period, about the time dinosaurs were evolving.
牙形刺最早出现于大约5亿年前，就在恐龙开始登上历史舞台时灭绝了。
Conodonts first emerged around 500 million years ago and died out just as dinosaurs were beginning to take shape.
牙形刺生活在寒武纪的海洋中，可能以某种浮游生物为食，不过没人清楚具体情况。
Conodonts lived in the Cambrian seas, and may have eaten certain types of plankton, but no one knows for sure.
应用推荐