Astraspida, or astraspids, are a small group of fossil, armored, fossil jawless vertebrates, which lived in the Middle Ordovician (about 450 million years ago) in North America. They are placed among the Pteraspidomorphi because of the large dorsal and ventral shield of their head armor. They are represented by a single genus, Astraspis, including possibly two species, A. desiderata and A.