Cyathaspis

Cyathaspis is the type genus of the heterostracan order Cyathaspidiformes.^[1] Fossils are found in late Silurian strata in the Cunningham Creek Formation, New Brunswick, Canada and Europe, especially in the Downton Castle Sandstone of Great Britain and Gotland, Sweden.^{[citation needed]} The living animal would have looked superficially like a tadpole, albeit covered in bony plates composed of the tissue aspidine, which is unique to heterostracan armor.^{[citation needed]}

Cyathaspis Temporal range: Wenlock to Ludlow
Reconstruction of C. banksii
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Pteraspidomorphi
Order:	Cyathaspidiformes
Family:	Cyathaspidae
Genus:	Cyathaspis Lankester
Type species
Pteraspis banksii Huxley and Salter, 1856
Species
C. acadica (Matthew 1886) C. banksii (Huxley & Salter 1856) C. barroisi (Leriche 1906) C. lindstromi Kiaer & Heintz 1935 C. ludensis C. macculloughi (Woodward 1891)

Cyathaspis ludensis is the earliest British vertebrate fossil.^{[citation needed]} It was found in rocks at Leintwardine in Herefordshire, a noted fossil locality.^{[citation needed]}