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词条 Daonella
释义
Daonella
fossil
genus of extinct pelecypods (clams) useful as a guide, or index, fossil in Triassic rocks. The shell is characterized by a wide dorsal region and by fine, radiating, riblike lineations. The shell is circular in outline and may show fine growth lines.
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更新时间:2024/11/11 7:13:55