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Placodermi
Placodermi Class of archaic, jawed (gnathostome), and heavily armoured fish, which appeared in the Devonian and which were virtually extinct by the end of that period. They were rather diverse in body form. They all possessed a head shield formed by bony plates. Pectoral and pelvic fins appear to have been present. Most of them (e.g. Coccosteus) were bottom-dwelling fish, with a depressed body terminating in a heterocercal tail.
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Cite this article
AILSA ALLABY and MICHAEL ALLABY. "Placodermi." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 30 May. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "Placodermi." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (May 30, 2012). http://www.encyclopedia.com/doc/1O13-Placodermi.html AILSA ALLABY and MICHAEL ALLABY. "Placodermi." A Dictionary of Earth Sciences. 1999. Retrieved May 30, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-Placodermi.html |
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Placodermi
Placodermi A class of archaic, jawed (gnathostome), and heavily armoured fish, which appeared in the Devonian Period and which were virtually extinct by its end. They were rather diverse in body form. They all possessed a head shield formed by bony plates. Pectoral and pelvic fins appear to have been present. Most of them were bottom-dwelling, with a depressed body terminating in a heterocercal tail.
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Cite this article
MICHAEL ALLABY. "Placodermi." A Dictionary of Zoology. 1999. Encyclopedia.com. 30 May. 2012 <http://www.encyclopedia.com>. MICHAEL ALLABY. "Placodermi." A Dictionary of Zoology. 1999. Encyclopedia.com. (May 30, 2012). http://www.encyclopedia.com/doc/1O8-Placodermi.html MICHAEL ALLABY. "Placodermi." A Dictionary of Zoology. 1999. Retrieved May 30, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O8-Placodermi.html |
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