heterostracan

English Thesaurus

1. extinct jawless fish with the anterior part of the body covered with bony plates; of the Silurian and Devonian (noun.animal)

hypernym	:	agnathan, jawless fish, jawless vertebrate,
definition	:	eel-shaped vertebrate without jaws or paired appendages including the cyclostomes and some extinct forms (noun.animal)

member meronym	:	heterostraci, suborder heterostraci,
definition	:	extinct group of armored jawless fishes or fish-like vertebrate; taxonomy is not clear (noun.animal)