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Placoderms Division
Subphylum:
Vertebrata The Placodermi were a class of armoured prehistoric fishes, known from fossils, which lived from the late Silurian to the end of the Devonian Period. Their head and thorax were covered by articulated armoured plates and the rest of the body was scaled or naked, depending on the species. Placoderms were among the first jawed fishes; their jaws likely evolved from the first of their gill arches. A 380 million year old fossil of one species represents the oldest-known example of live birth. The first identifiable Placoderms evolved in the late Silurian; they began a dramatic decline during the Late Devonian extinctions, and the class was entirely extinct by the end of the Devonian. The oldest known fossils are found in China. Order:
Antiarchi
Class: Sarcopterygii (class of lobe-finned fishes, consisting of lungfish and coelacanths)
Subclass: Coelacanthimorpha Coelacanth is the common name for an order of fish that includes the oldest living lineage of gnathostomata known to date. The coelacanths, which are related to lungfishes and tetrapods, were believed to have been extinct since the end of the Cretaceous period, until the first Latimeria specimen was found off the east coast of South Africa, off the Chalumna River in 1938.
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