甘肃窑街中侏罗世Coniopteris spectabilis的原位孢子及锥叶蕨属的时空分布  

The in situ spores of Coniopteris spectabilis in the Middle Jurassic from Yaojie Formation,Gansu,and the tempo-spatial distribution of Coniopteris

作　　者：辛存林[1] 王露菡 季健健 张亚梅 

机构地区：[1]西北师范大学地理与环境科学学院,甘肃兰州730070

出　　处：《西北大学学报（自然科学版）》2017年第6期896-906,共11页Journal of Northwest University（Natural Science Edition）

基　　金：国家自然基金资助项目(41262001)

摘　　要：对在甘肃窑街中侏罗统窑街组发现的真蕨类化石进行系统描述,通过与相似种的蕨叶、叶脉、羽片、小羽片分裂的程度及裂片形状等特征的对比,明确该化石植物为Coniopteris spectabilis Brick。通过实验分析揭示出C.spectabilis的原位孢子基本特征:极面观为三角形、圆三角形,顶角钝圆,三边线平直或微凸;赤道面观为半圆形、椭圆形,近极微突出;极面观直径38~54μm,平均46μm;三射线平直或微弯,部分隆起为脊线状。同时,将其与窑街地层中相似分散孢子的形态、直径、三射线等特征对比后认为,Deltoidospora irregularis是C.spectabilis的孢子,后者为前者的母体植物。基于中国已发现的44种锥叶蕨的时空分布记录发现,从早侏罗世到早白垩世,中国锥叶蕨属分布总体呈向北推移的趋势,分布范围逐渐缩小,也反映出适宜锥叶蕨生长的温带气候区的总体分布也相应地有向北推移的趋势。A fossil identified as Coniopteris was collected from the Middle Jurassic Yaojie Formation of Yaojie Basin in Gansu Province,Northwest China. On the basis of the comparison between the characteristics( especially the morphology of pinnules),it was confirmed as Coniopteris spectabilis Brick. In situ spores of C. spectabilis are triangular with rounded apex angles in polar view and half round or oval in equatorial view. Three sides and radius are straight or slightly convex,and parts of radius are raised. The comparison between in situ spores and dispersed spores suggests that Deltoidospora irregularis is the spore of C. spectabilis. And the tempo-spatial distribution of Coniopteris occurred in Mesozoic of China shows that the diversity of this genus has a northward reduced trend during Early Jurassic to Early Cretaceous. Accordingly this change could reflect that the warm-temperate humid climatic region,which is fit for Coniopteris,has a similar changing trend.

关 键 词：Coniopteris spectabilis 原位孢子 中侏罗世 窑街组 锥叶蕨属 时空分布 

分 类 号：Q913[天文地球—古生物学与地层学]