- any of several extinct jawless fishes of the Ordovician, Silurian, and Devonian periods, having the body enclosed in an armor of bony plates.
Origin of ostracoderm
1890–95; < New Latin Ostracodermi, plural ofOstracodermus < Greek ostrakódermos with a shell, equivalent to óstrako(n) shell, tile + -dermos -derm
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- any extinct Palaeozoic fishlike jawless vertebrate of the group Ostracodermi, characterized by a heavily armoured body
C19: via New Latin from Greek ostrakon shell + -derm
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
- Any of various extinct primitive jawless fishes of the Ordovician through the Devonian Period. Most ostracoderms had their heads or entire bodies encased in fused bony plates. Some or all ostracoderms are sometimes classified together with the modern cyclostomes (lampreys and hagfish).
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