Pteraspididae is an extinct family of heterostracan vertebrates. Poraspis is an extinct genus of heterostracan. Psammmosteida also called as Psammosteoidei is a suborder of pteraspidid heterostracan agnathans. Rhinopteraspis is an extinct genus of pteraspidid heterostracan agnathan. Edaphaspis bystrowi is an extinct amphiaspidid cyathaspidid heterostracan. Ariaspidae is a family of extinct cyathaspidiform heterostracan agnathans in the suborder Cyathaspidida.