Cyathaspis

{{Short description|Extinct genus of jawless fishes}}{{Italic title}}

{{Taxobox

| name = Cyathaspis

| image = Cyathaspis banksii.jpg

| image_caption = Reconstruction of C. banksii

| fossil_range = Wenlock to Ludlow

| regnum = Animalia

| phylum = Chordata

| classis = Pteraspidomorphi

| ordo = Cyathaspidiformes

| familia = Cyathaspidae

| genus = Cyathaspis

| genus_authority = Lankester

| type_species = Pteraspis banksii

| type_species_authority = Huxley and Salter, 1856

| subdivision_ranks = Species

| subdivision =

• C. acadica {{small|(Matthew 1886)}}
• C. banksii {{small|(Huxley & Salter 1856)}}
• C. barroisi {{small|(Leriche 1906)}}
• C. lindstromi {{small|Kiaer & Heintz 1935}}
• C. ludensis
• C. macculloughi {{small|(Woodward 1891)}}

}}

Cyathaspis is the type genus of the heterostracan order Cyathaspidiformes.{{Cite book |last=Matthew |first=George Frederic |url=https://books.google.com/books?id=PUQsAAAAYAAJ&dq=On+Some+Remarkable+Organisms+of+the+Silunian+and+Devonian+Rocks+in+Southern+New+Brunswick&pg=PA49 |title=On Some Remarkable Organisms of the Silunian and Devonian Rocks in Southern New Brunswick |date=1888 |pages=52–54 |language=en}} 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.{{cn|date=June 2020}} 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.{{cn|date=June 2020}}

Cyathaspis ludensis is the earliest British vertebrate fossil.{{cn|date=June 2020}} It was found in rocks at Leintwardine in Herefordshire, a noted fossil locality.{{cn|date=June 2020}}