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甘肃平凉的平凉组和新疆柯坪大湾沟的萨尔干组中具有大量保存良好的Ningxiagraptus(宁夏笔石属)标本,为其研究提供了极佳的化石材料。本文结合新发现的材料,对Ningxiagraptus的分类位置进行厘定,对其变革历史中存在的若干问题进行讨论,为深入研究笔石的分类提供一个可供参考的案例。在对正笔石目笔石的分类和亲缘关系判别时,以笔石体的始端发育型式和特征为主,辅以笔石枝的结合方式及胞管性质是可行的方法。Ningxiagraptus虽具简单直管状胞管,第2个胞管自胎管口部向上转曲伸出,构成“U”字形始端,但其始端发育型式和始端形态却与Dicellograptus(叉笔石)近似,故将Ningxiagraptus归属有轴亚目的双头笔石超科。
The well-preserved Ningxia graptus (Nymphaeaceae) specimen from the Pingliang Formation in Pingliang, Gansu Province and the Salkan Formation in Dawanggou, Keping, Xinjiang provided excellent fossil materials for its study. Based on the newly discovered materials, this article determines the classification position of Ningxiagraptus and discusses some problems in its history of change. It provides a reference case for further research on the classification of Penoliths. When the classification and kinship of penoliths of Penolith are correct, the main types and characteristics of penoliths are mainly the development of penoliths, and the combination of Pencil branches and the properties of cell tubes are feasible. Ningxiagraptus has a simple straight tubular cell tube. The second cell tube extends upwardly from the mouth of the fetal tube and forms the beginning of the “U” shape. However, its initial development pattern and initial morphology are similar to those of Dicellograptus Approximation, it will Ningxiagraptus attributed to the sub-head axis sub-head stone superfamily.