placoderm

pla·co·derm  (plk-dûrm)

n.

Any of various extinct fishes of the Silurian and Devonian periods, characterized by bony plates of armor covering the head and flanks, hinged jaws, and paired fins.

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[New Latin Placoderm, class name : Greek plax, plak-, flat stone, plate; see plk-¹ in Indo-European roots + -derm.]

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placoderm [ˈplækəˌdɜːm]

n

(Earth Sciences / Palaeontology) any extinct bony-plated fishlike vertebrate of the class Placodermi, of Silurian to Permian times: thought to have been the earliest vertebrates with jaws

[from Greek plac-, plax a flat plate + -derm]

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placoderm  (plk-dûrm)

Any of various extinct fishes of the class Placodermi of the Silurian and Devonian Periods, characterized by bony plates of armor covering the head and flanks. The bodies of placoderms were spindle-shaped or flattened, and their skeletons were usually partially bony and included a cranium. Placoderms were the first group of fish to evolve jaws, but are not closely related to the jawed fish of today.

Thesaurus

Noun

1.

placoderm - 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 aquatic vertebrate - animal living wholly or chiefly in or on water class Placodermi, Placodermi - extinct group of bony-plated fishes with primitive jaws