placoderm
noun
plac·o·derm
ˈpla-kə-ˌdərm 
: any of a class (Placodermi) of extinct chiefly Devonian fishes with an armor of bony plates and primitive jaw structures
Examples of placoderm in a Sentence
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Known as placoderms, these primitive jawed vertebrates came in all shapes and sizes, from small bottom-dwellers to giant filter-feeders.
—
Jack Tamisiea,
New York Times,
30 Jan. 2024
Dunkleosteus, a genus from a class of armored fish called the placoderms, reached greater dimensions and could have easily preyed on early chondrichthyans.
—
Joshua Rapp Learn,
Discover Magazine,
1 Apr. 2023
From one layer to the next one above, no more trilobites or nightmarish placoderms or dimetrodons—entire animal reigns and ecosystems have vanished.
—
Manu Saadia,
Ars Technica,
4 Sep. 2017
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Jack Tamisiea,
New York Times,
30 Jan. 2024
Dunkleosteus, a genus from a class of armored fish called the placoderms, reached greater dimensions and could have easily preyed on early chondrichthyans.
—
Joshua Rapp Learn,
Discover Magazine,
1 Apr. 2023
From one layer to the next one above, no more trilobites or nightmarish placoderms or dimetrodons—entire animal reigns and ecosystems have vanished.
—
Manu Saadia,
Ars Technica,
4 Sep. 2017
Cite this Entry
“Placoderm.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/placoderm. Accessed 5 Jul. 2026.
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