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Name: Pteraspis ‭(‬Wing shield‭)‬.
Phonetic: Teh-rass-pis.
Named by: Agassiz - 1835.
Classification: Chordata,‭ ‬Heterostraci,‭ ‬Pteraspidiformes,‭ ‬Pteraspidae.
Species: P. crouchi, P. rostratus, P. stensioei, possibly others.
Diet: Carnivore.
Size: 20‭ ‬centimetres long.
Known locations: Europe, particularly Belgium and Britain.
Time period: Lochkovian to Emsian of the Devonian.
Fossil representation: Many specimens known.

       Pteraspis gets its name from the growths on the sides of its main body‭ '‬shield‭’‬.‭ ‬These served acted as hydrofoils,‭ ‬the job usually done by the pectoral fins which are absent in Pteraspis.‭ ‬The lower lobe of the tail is also larger than the upper which would provide upwards lift.‭ ‬The spine that rose up from the back of the shield would have served the purpose of a dorsal fin,‭ ‬as well as potentially providing some protection from predators.‭ ‬The hard rostrum that projects forward would have provided additional streamlining,‭ ‬but it is uncertain if this was the only purpose for its presence. These adaptations all point to a fish that probably swam upwards into open water rather than cruising around the bottom.‭ ‬The chosen food source of Pteraspis is thought to have been small open water vertebrates like shrimp.

Further reading
- On Cephalaspis and Pteraspis - Quarterly Journal of The Geological Society 01/1858; 14:267-280. - T. H. Huxley - 1858.
- On the occurrence of a fish (Pteraspis) in the lower Ludlow rock - Annals and Magazine of Natural History: Series 3 - vol 4 issue 19 - J.W. Salter F.G.S. - 1859.
- The ostracoderm Pteraspis Kner and the relationships of the Agnathous vertebrate - Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences, Vol. 225 (1935), Issue 527v - Errol I White - 1935.
- The Functional Significance of the Hypocercal Tail in Pteraspis Rostrata. - The Journal of Experimental Biology 20. - K. A. Kermack - 1941.
- Pteraspis leathensis White, a Dittonian zone-fossil - Bulletin of The British Museum (Natural History) Geology vol 1 p69-89 - E. I. White - 1950.
- Notes on Pteraspis mitchelli and its associated fauna. - Transactions of the Edinburgh Geological Society, v. 19:306-322 - E. L. White - 1963.


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