anaspida

• 无颌类脊椎动物的一个已灭绝目，生存于志留纪和泥盆纪。

An extinct order of jawless vertebrates, known from the Silurian and Devonian periods.

专有名词

1. Extinct jawless vertebratesC2formalscientific

   An extinct order of jawless vertebrates that lived during the Silurian and Devonian periods, characterized by a scaleless body and a series of gill openings.

   无颌类

   • Fossils of Anaspida have been found in marine sediments from the Silurian period.
   • The Anaspida are considered an early group of vertebrates that lacked jaws.
   • Paleontologists study Anaspida to understand the evolution of early fish.