['plækәdә:m]
n.
[古生]盾皮鱼

[ noun ]
fish-like vertebrate with bony plates on head and upper body; dominant in seas and rivers during the Devonian; considered the earliest vertebrate with jaws
<noun.animal>

Placoderm \Plac"o*derm\, n. [Gr. pla`x, plako`s, tablet + de`rma
skin.] (Paleon.)
One of the Placodermi.