Definition of ostracoderm in English:

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Pronunciation: /ˈästrəkōˌdərm/


An extinct jawless fish of the Cambrian to Devonian periods, having a heavily armored body.
  • Class Agnatha: several orders.
Example sentences
  • By the Middle Devonian the armoured jawless ostracoderms were in decline, and instead the jawed fish were undergoing a great evolutionary radiation in both the sea and in freshwater.
  • With their armored head shield and trunk shield composed of overlapping bony plates, the placoderms appear at first glance extremely similar to the ostracoderms (armoured jawless fish).
  • These were jawless, armored fish informally called ostracoderms, but more correctly placed in the taxon Pteraspidomorphi.


Late 19th century: from modern Latin Ostracodermi (former taxonomic name), from Greek ostrakon 'shell' + derma 'skin'.

For editors and proofreaders

Syllabification: os·tra·co·derm

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