Liptobiolites occur only in the primary generation and in the early stage of the middle generation.

残植煤类仅出现在初始世代和中期世代的早期阶段。

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Liptobiolites occur only in the primary generation and in the early stage of the middle generation.

残植煤类仅出现在初始世代和中期世代的早期阶段。

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