cephalaspid
/səˈfæləspɪd/
noun
- An extinct jawless fish of the order Cephalaspidiformes, having a bony head shield.
- The cephalaspid lived in shallow seas during the Silurian and Devonian periods.
- Fossils of the cephalaspid show a distinctive shield covering its head.
- Scientists study the cephalaspid to understand early vertebrate evolution.