Heterostraci

== Translingual == === Etymology === From hetero- (“different”, from Ancient Greek ἕτερος (héteros)) +‎ Latin ostracī (“ostracum/ostracon”, genitive noun), literally “of differing ostraca”. === Proper noun === †Heterostraci A taxonomic subclass within the class Pteraspidomorphi – extinct pteraspidomorph jawless vertebrates that lived primarily in marine and estuary environments. === See also === Heterostraci on Wikipedia.Wikipedia Heterostraci on Wikispecies.Wikispecies Category:Heterostraci on Wikimedia Commons.Wikimedia Commons