Callistophytalean pteridosperms from Permian aged floras of China
Callistophytalean pteridosperms from Permian aged floras of China
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DOI：
10.1111/j.1475-4983.2010.01025.x
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发表时间：
2011-03
期刊：
影响因子：
2.6
通讯作者：
L. Seyfullah;J. Hilton
中科院分区：
文献类型：
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作者：
L. Seyfullah;J. Hilton
摘要：最近对中国二叠纪植物群的研究强调了广泛存在的calistophytalean蕨类植物，挑战了以前对其时空分布和多样性的理解。在中国，该群跨越二叠纪时期，在许多泥炭形成环境中构成了独特但罕见的成分。在中国北方太原组的化石中，发现了最早的产于Asselian-Sakmarian期的Callistophytalean化石，包括在煤核组合中的Callospermarion undulatum的胚珠，以及在压陷组合中的Norinosperma shanxiensis的排卵复叶和Norinotheca shanxiensis的合缝复叶。化石记录中更丰富的是Roadian-Wordian阶段的adpression遗骸，下石盒子组保存了大量的营养和排卵的Emplectopteris triangularis遗骸，现在被认为是代表了一个callistophytalean。已知最年轻的Callistophytalean来自吴柴坪-长兴阶，中国南部的宣威组含有一个Callistophyton boyssetii的单茎，这为该群体在二叠纪末大灭绝之前提供了无可争议的证据。通过对花粉记录的分析，这些解释得到了补充，这些花粉记录表明，从二叠纪开始，在中国北方和南方，包括上石盒子组，石先锋群，宣威组，以及可能也在中宾夕法尼亚本溪组的孢粉组合中，Calistophytalean花粉属Vesicaspora是广泛分布的。尽管这些化石在包含它们的组合中并不常见，但它们证明了中国北方二叠纪的彭萨科拉亚期到瓜达卢普早期和中国南方二叠纪的乐平期的calistophytalean蕨类植物的连续性。目前的物种，Callistophyton boyssetii和Callospermarion undulatum都是已知的宾夕法尼亚州最早的二叠纪时代植物群的欧美，而Norinosperma，Norinotheca和Emplectopteris似乎代表特有的华夏元素。结果表明，calistophytalean pteridosperms不能再从后石炭纪植物进化和植物区系的理论排除，似乎在二叠纪和石炭纪的年龄植物群落中发挥了重要作用。在几个尚未确定宏观遗骸的地层中存在Vesicaspora是一个有希望的指示，表明尚未发现更多的calistophytalean pteridosperms。
Abstract: Recent investigations into Permian aged floras from China have highlighted the widespread occurrence of callistophytalean pteridosperms that challenge previous understanding of their spatial and temporal distribution and diversity. In China, the group spans the Permian period and constitutes a distinctive but rare component in many peat‐forming environments. The stratigraphically earliest callistophytalean occurs in the Asselian‐Sakmarian stages with fossils from the Taiyuan Formation of northern China including ovules of Callospermarion undulatum in coal ball assemblages, and ovulate fronds of Norinosperma shanxiensis and synangiate fronds of Norinotheca shanxiensis in adpression assemblages. More abundant in the fossil records are adpression remains from the Roadian‐Wordian stages with the Lower Shihhotse Formation preserving abundant vegetative and ovulate remains of Emplectopteris triangularis that is now considered to represent a callistophytalean. The youngest callistophytalean recognised is from the Wuchaipingian‐Changhsingian stages with the Xuanwei Formation of southern China containing a single stem of Callistophyton boyssetii that provides indisputable evidence of the group in the lead up to the end‐Permian mass extinction. These accounts are augmented by analysis of pollen records that demonstrate the callistophytalean pollen genus Vesicaspora to be widespread through palynological assemblages from the Permian period in both North and South China, including the Upper Shihhotse Formation, Shihchienfeng Group, Xuanwei Formation, and possibly also in the mid‐Pennsylvanian Benxi Formation. Although macrofossil specimens are uncommon elements in the assemblages that contain them, they demonstrate the continuity of callistophytalean pteridosperms from the Pennsylvanian sub‐period into the early Guadalupian epoch of the Permian in North China and into the Lopingian epoch of the Permian in South China. Of the species present, both Callistophyton boyssetii and Callospermarion undulatum are known from the Pennsylvanian–earliest Permian age floras of Euramerica, whereas Norinosperma, Norinotheca and Emplectopteris appear to represent endemic Cathaysian elements. Results imply that callistophytalean pteridosperms can no longer be excluded from theories of post‐Carboniferous plant evolution and floristics, appearing to have played an important role in both Permian and Carboniferous aged plant communities. The presence of Vesicaspora in several formations from which macro‐remains have not been identified is a hopeful indicator that further callistophytalean pteridosperms are yet to be found.