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

发布时间：2019-03-22 06:53

【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。
[Abstract]:A systematic description of the fern fossils found in the Middle Jurassic Yaojie formation in Yaojie, Gansu Province was carried out. By comparing the characteristics of the fern leaves, veins, pinnae, pinnae and small pinnae of similar species, and the shape of the segments, the fossil plant was identified as Coniopteris spectabilis Brick.. The basic characteristics of in situ spores of C.spectabilis were revealed by experimental analysis: the polar view is triangle, circular triangle, the apex angle is obtuse, the trilateral line is straight or slightly convex, the equatorial view is semicircular, ellipsoid, nearly micro-protruding; The diameter of the polar surface is 38 ~ 54 渭 m (average 46 渭 m), and the three-ray is straight or slightly curved, and some of the protuberances are ridge-like. At the same time, it is considered that, Deltoidospora irregularis is the spores of C.spectabilis, and the latter is the parent plant of the former, after comparing the morphology, diameter and three-ray characteristics of dispersed spores similar to those in Yaojie Strata. Based on the temporal and spatial distribution records of 44 species of Dryopteris species found in China, it was found that from early Jurassic to early Cretaceous, the distribution of the genus Dryopteris from early Jurassic to early Cretaceous generally showed a northward trend, and the distribution range gradually decreased. It also reflects that the overall distribution of temperate climates suitable for the growth of Dryopteris conifera has a tendency to move northward accordingly.
【作者单位】：西北师范大学地理与环境科学学院;
【基金】：国家自然基金资助项目(41262001)
【分类号】：Q914

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