Ostracodermi
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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.
Ostracodermi
the oldest vertebrates. They are known from Silurian and Devonian deposits. The vertebrates measured up to 2 m long. They had an internal cartilaginous skeleton and an external shell made up of separate plates or small scales. Together with the extant Cyclostomata, the Ostracodermi belong to the Agnatha. They are significant in determining the stratigraphy of the Devonian.
REFERENCE
Osnory paleontologii: Bescheliustnye, ryby. Moscow, 1964.The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.