| 论似发珊瑚(Pilophyllia Ge et Yü,1974)的分类位置和演化特征 |
| 点此下载全文 |
| 引用本文：王鸿祯,何心一,陈建强.1986.论似发珊瑚(Pilophyllia Ge et Yü,1974)的分类位置和演化特征[J].地球学报,8(1):95-105. |
| DOI： |
| 摘要点击次数: 4418 |
| 全文下载次数: 4666 |
|
|
| 中文摘要:Pilophyllia Ge et Yü,1974是我国扬子区志留系中常见的属,在陕南宁强组中尤为丰富。该属为单体,隔壁为包珊瑚型,幼年期隔壁几乎全由层状组织组成,青年期以后隔壁核心为羽状组织外覆层状组织,横板大多完整平列或呈束状组合,具较宽的边缘厚结带。可能直接由Amplexoides演化而来。演化趋向主要表现为随层位的变化隔壁的层状组织逐渐被羽状组织所代替。根据隔壁类型和个体形态特征及出现时代先后,Pilophyllia应归入包珊瑚科。它是该科中进化的一支,以发育复羽?为特征。文中描述了三个新种:Pilophyllia simplex Chen,P.alternata Chen,P.densitabulata Chen。 |
| |
| ON THE TAXONOMIC POSITION AND EVOLUTIONARY TREND OF PILOPHYLLIA GE et Yü, 1974 |
|
|
| Abstract:The diagnosis of the genus is supplemented in terms of septal type and minute skeletal structures. The septa of Pilophyllia are clearly amplexoid, and are composed mainly of lamellar sclerenchyme in the proximal part of the corallum, but are characterized by development of trabeculae in the upper part. The outer part of septa in the peripheral stereozone are thick and contiguous, containing stout rhabdacanth trabeculae invested with lamellar tissue. The septa grow suddenly thin beyond the stereozone, but still comprise rhabdacanth trabeculae that are developed upon the successive tabular floors.The clear boundary and evident difference between the juxtaposed and well-preserved lamellar and fibrous tissue as seen within the septa indicate that the idea of secondary origin of the lamellar structure of the skeleton is not tenable.There are altogether 14 species and subspecies of the genus, among which, the three new ones, Pilophyllia simplex Chen, P. alternata Chen and P. densi-tabulata Chen are described here. Only three species occur in the Lower Silurian. A comparison of the various species show that a clear tendency existed for the fibrous structure, i. e. the trabeculae, to develop at the expense of lamellar structures at higher horizons (PⅠ. Ⅱ, Fig. 1-4). Other evolutionary trends include thickening of the septs and increasing width of the stereozone.On the basis of skeletal structures, Pilophyllia is attributed to Family Amplexidae, which is characterized by amplexoid septa and progressive development of fibrous skeletal structures. Two groups may be recognized in the family,a primary group dominated by the lamellar tissue of septa throughout, including Amplexoides, Lindstroemophyllum, probably also Zelophyllum and the Late Ordovician compound form Crenulites, in addition to the Carboniferous Amplexus and Bordenia, and an advanced group with a progressive development of trabeculate septa, including Pilophyllia and Protopilophyllum. The Devonian Si phono phrentis and Heterophrentis with complete septa may not be included in this family. |
| 查看全文 查看/发表评论 下载PDF阅读器 |
|
|
|
|
|
