Definition of ostracoderm in English:

ostracoderm

noun

  • An early jawless fossil fish of the Cambrian to Devonian periods, having a heavily armoured body.

    • ‘If lancelets and the fossil ostracoderms are considered out-groups to living craniates, then the brains of the earliest craniates must have been very small for their body size.’
    • ‘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.’
    • ‘These were jawless, armored fish informally called ostracoderms, but more correctly placed in the taxon Pteraspidomorphi.’
    • ‘Enamel, or enameloid tissue covering tubercles, was clearly described in Ordovician vertebrates such as the ostracoderms.’
    • ‘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).’

Origin

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

Pronunciation

ostracoderm

/ɒˈstrakədəːm/