An Early Triassic conodont with periodic growth?
An Early Triassic conodont with periodic growth?
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具有周期性生长的早三叠世牙形刺？
DOI：
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发表时间：
1997
影响因子：
2
通讯作者：
P. Donoghue
中科院分区：
文献类型：
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作者：
Zhang Shunxin;R. Aldridge;P. Donoghue
桂西下三叠统北寺组一个新的三叠纪牙形石属Parapachycladina的元素在隐性基缘显示出特征性的层状边缘。薄片以8-10个为一组，每组之间有很宽的层间空间。如果这种明显的周期性反映了年周期，那么这些标本停止生长时的年龄不超过4岁。
Elements of a new Triassic conodont genus Parapachycladina, from the Lower Triassic Beisi Formation of western Guangxi Province, China, show a characteristic pattern of lamellar edges in the recessive basal margin. The lamellae are grouped in sets of 8–10, with broad interlamellar spaces between each set. If this apparent periodicity reflects annual cycles, the specimens were not more than four years old when they ceased growing.