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Placodermi |
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Placodermi [‚pla·kə′dər·mē]
(paleontology) A large and varied class of Paleozoic fishes characterized by a complex bony armor covering the head and the front portion of the trunk. Placodermi a class of extinct fishes that lived during the Devonian. Their length was up to 5–6 m. The head and anterior part of the trunk were covered with an armor of bony plates of cutaneous origin. The plates were nodular and ridged. The head and trunk sections of the armor were articulated, and the jaws consisted of pointed bony plates. There were two subclasses: Arthrodira and Antiarchi (which included the genus Bothriole-pis). REFERENCEDrushits, V. V., and O. P. Obrucheva. Paleontologiia, 2nd ed. [Moscow] 1971.Want to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit the webmaster's page for free fun content. |
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No references found | Long said that the claspers were used by the ancient fish, an extinct class of armoured fish called placoderms, to grip inside the female while they were mating. Vertebrates described in earlier studies include psammosteids (Obruchev & Mark-Kurik 1965; Mark-Kurik 1968, 1995), placoderms (Karatajute-Talimaa 1963), acanthodians (Valiukevicius 1998), and sarcopterygians (Vorobyeva 1977). Dunkleosteus was one of many species of placoderms, a diverse group of armoured fishes that dominated aquatic ecosystems during the Devonian period, from 415 million to 360 million years ago. |
Placoderms |
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