Anaspida

Anaspida; Temporal range: early Silurian - Late Devonian
	Cowielepis
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Infraphylum:	Agnatha
Superclass:	†Anaspidomorphi
Class:	†Anaspida; Traquair, 1899
Type species
	†Birkenia elegans; Traquair 1898
Orders
	Endeiolepidiformes; Birkeniiformes;
Synonyms
	Anaspidi; Birkeniae;

Anaspids are characterized by a large, tri-radiate spine (red) posteriorly to the series of branchial openings. It is assumed that the most primitive anaspids, such as *Pharyngolepis* (top), possessed a long, ribbon-shaped, ventrolateral fin-fold (green). More advanced forms, such as *Rhyncholepis* (bottom), possessed a shorter paired fin-fold (green) and enlarged, spine-shaped, median dorsal scutes. – Philippe Janvier

Anaspida ("shieldless ones") is an extinct group of jawless fish that existed from the early Silurian period to the late Devonian period. They were classically regarded as the ancestors of lampreys, but this is denied in recent phylogenetic analyses, although some analyses show these groups would be at least related. Anaspids were small marine fish that lacked a heavy bony shield and paired fins, but were distinctively hypocercal.