Noun: osteostracan
- Extinct jawless fish of the Devonian with armoured head
"Osteostracans had a distinctive head shield and are thought to be closely related to modern vertebrates";
- cephalaspid
Derived forms: osteostracans
Type of: agnathan, jawless fish, jawless vertebrate
Part of: Cephalaspida, Osteostraci, suborder Cephalaspida, suborder Osteostraci
Encyclopedia: Osteostracan