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出典:『Wikipedia』 (2011/05/20 18:26 UTC 版)

英語による解説

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The Petalichthyida was an order of small, flattened placoderm fish. They were typified by their splayed fins, and numerous tubercles that decorated all of the plates and scales of their armor. They reached a peak in diversity during the Early Devonian and were found throughout the world, particularly in Europe (especially in Germany), North America, Asia, South America, and Australia. The petalichthids Lunaspis and Wijdeaspis are among the best known. There was an independent diversification event that occurred in what is now Southern China, producing a handful of unique genera that were once placed in their own order, "Quasipetalichthyida," named after the first discovered species there, Quasipetalichthys haikouensis. Soon after the Petalichthids' diversification, they went into a decline, until the last few species were exterminated along with the rest of the placoderms during the Late Devonian extinction event.