NOUN
- extinct jawless fish with the anterior part of the body covered with bony plates; of the Silurian and Devonian
How To Use heterostracan In A Sentence
- The symmetrical, diphycercal tail, not perfected by gnathostomes until the Cretaceous, was standard equipment on heterostracans in the Silurian.
- Both the endo- and exoskeleton is made up of true bone with cell spaces (the heterostracans have acellular bone).
- The Heterostracan head is covered with several armoured plates, the body with large scales and the tail is most often diphycercal.