Cyathaspidida is a taxon of extinct cyathaspidiform heterostracan agnathans whose fossils are found in Silurian to Lower Devonian marine strata of Europe and North America.

The cyathaspidids of Cyathaspidida were tadpole-like animals with drum-shaped, cigar-shaped or wedge-shaped cephalothoraxes, and were anatomically similar to several other heterostracan groups.

In 2013, Lundgren and Blom reassessed several specimens of cyathaspidids, and reorganized them into three families, Cyathaspidae, Ariaspidae and Ctenaspidae.

In addition to the type genus, Cyathaspis, Cyathaspidae contains the following genera: Americaspis, Archegonaspis, Capitaspis, Dikenaspis, Dinaspidella, Homaspidella, Irregulareaspis, Nahanniaspis, Pionaspis, Poraspis, Ptomaspis, Seretaspis, Steinaspis, Torpedaspis, and Vernonaspis.

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