The Upper Cambrian bradoriid ostracod Cyclotron lapworthi is a hesslandonid
The Upper Cambrian bradoriid ostracod Cyclotron lapworthi is a hesslandonid
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DOI：
10.1017/s0263593300003527
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发表时间：
1994
期刊：
影响因子：
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通讯作者：
M. Williams;D. Siveter;A. Rushton;V. Berg-Madsen
中科院分区：
文献类型：
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作者：
M. Williams;D. Siveter;A. Rushton;V. Berg-Madsen
摘要本文重新描述了英国寒武纪中为数不多的几个已获大量标本的缓形介形类之一的Cyclotron laparani（Groom，1902）。它有一个内背，因此表明hesslandonid的亲和力。对C.在个别换羽阶段上，lapalani没有明显的区别，但在节和叶的发育上却有明显的变化。C. laparani的甲壳形状变化很大，这可能表明它的瓣膜很薄，相对柔软。在英国和加拿大C. laponii仅限于上寒武统Olenus带。C. lapsatii也可能同时出现在瑞典的上寒武统。
Abstract Cyclotron lapworthi (Groom, 1902), one of the few British Cambrian bradoriid ostracod species known from a large number of specimens, is redescribed. It has an interdorsum, thus indicating a hesslandonid affinity. The ontogeny of C. lapworthi does not demonstrate a clear distinction of its individual moult stages but does show marked changes in the development of nodes and lobes. C. lapworthi shows wide variation in carapace shape possibly indicating that its valves were thin and relatively flexible. In England and Canada C. lapworthi is restricted to the Upper Cambrian Olenus Zone. C. lapworthi may also occur coevally in the Upper Cambrian of Sweden.