arthrodire

Noun

 * 1)  Any member of the extinct order, armored jawed fishes that flourished in the Devonian period.
 * 2) * 2009 January 15, Martin D. Brazeau, “The braincase and jaws of a Devonian 'acanthodian' and modern gnathostome origins”, Nature Volume 457 No. 7227, doi:10.1038/nature07436:
 * The basicranial circulation of Ptomacanthus resembles that in arthrodire placoderms.