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Any of various extinct jawed fishes of the group Placodermi of the Silurian and Devonian Periods, having bony plates of armor covering the head and thorax. Placoderms were among the first jawed vertebrates.

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


(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
[C19: from Greek plac-, plax a flat plate + -derm]


(ˈplæk əˌdɜrm)

any of various extinct jawed fishes of the class Placodermi, chiefly of the Devonian Period: many were armored in bony plates.
[1855–60; < New Latin Placodermi name of the class, pl. of placodermus=placo- (< Greek; see placoid, -o-) + -dermus -derm]
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.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
References in periodicals archive ?
Matt Friedman, a paleobiologist at Oxford University, said: "If you look at just the top of the skull and the body, it looks like a placoderm.
Storm origin of bone-bearing beds in the Lower Devonian placoderm sandstone from Podlazie Hill (Holy Cross Mountains, central Poland).
The scientists studied the skull of Romundina, an early armoured fish with jaws, or placoderm, from arctic Canada.
To find out, he says, the researchers first need to confirm that the muscles were present in all types of placoderms, not unique to the one placoderm group studied.
The almost complete skeleton of the placoderm Heterostius ingens Asmuss is found at the same level in the Arukula deposits near Belogorka village (Ivanov et al.
Lead author Min Zhu, of the Chinese Academy of Sciences' Institute of Vertebrate Paleontology and Paleoanthropology, added that entelognathus was "a placoderm, an extinct grade of primitive armored fishes.
It resembles a tiny tooth and I'm wondering if it might be from a placoderm fish.
Later Vasiliauskas (1963) provided the description of the placoderm Phyllolepis tolli and a list of vertebrate taxa from this locality.
The psammosteid and placoderm fish fossils have been used as characteristic or zonal forms in the Baltic area (Gross 1933, 1942; Sorokin 1981) and on the whole of the East European Platform (Rzhonsnitskaya & Kulikova 1990) since the last century.