Anaspid

Anaspids are a group of extinct jawless fish that lived during the Ordovician and Silurian periods, approximately 485 to 419 million years ago. They are characterized by their distinctive, flat, and elongated bodies, which are typically less than 10 centimeters in length. Anaspids are known for their unique feeding mechanism, which involved using their elongated, tooth-like structures to filter food from the water.

The most well-known anaspid is the genus Pteraspidella, which had a distinctive sail-like fin on its back. This fin was likely used for swimming and possibly for communication or courtship displays. Anaspids are believed to have been bottom-dwelling creatures, feeding on organic matter and small invertebrates.

The fossil record of anaspids is extensive, with numerous species described from various locations around the world. They are an important group of fossils for understanding the early evolution of vertebrates, as they represent one of the earliest known groups of jawless fish. Anaspids are also significant in the study of paleoecology, as they provide insights into the diversity and adaptations of early marine ecosystems.