论埃迪卡拉纪微体球状化石Schizofusa与Leiosphaeridia的关系

埃迪卡拉纪是新元古代最后一个纪,是新元古代雪球地球事件与寒武纪生命大爆发之间地质历史最重要的转折时期,在研究地球早期生命演化方面具有举足轻重的地位。我国华南三峡地区埃迪卡拉系陡山沱组中下部的地层中,发现了大量的以具刺疑源类为主的微体化石,其中有两个形态简单、分布广泛的类型——分别是以光面、球状为特征的Leiosphaeridia和光面囊胞状、具开裂特征的Schizofusa。本文通过对这两种化石材料的细致观察与统计,对两者间的亲缘关系进行了详细探讨,认为Schizofusa开裂之前应为光面球体,即Schizofusa是某些光面球的发展演化后期阶段。

DISCUSSION ON THE RELATIONSHIP BETWEEN THE EDIACARANSCHIZOFUSA AND LEIOSPHAERIDIA(ACRITARCHS)

Ediacaran is the last period in the Neoproterozoic,also a key period between the Neoproterozioc"snowball earth"events and the Cambrian"explosion",having apivotal position in the study about the evolution of early life in earth history.From the lower and middle part of the Doushantuo Formation in the Yangtze Gorges area of South China,a large amount of acritarchs are found.Among them,there are two types of simple acritarch which have a wide range of distribution.One is Leiosphaeridia tenuissima which characterized by sphere with smooth surface;The other is Schizofusa zangwenlongii which characterized by sphere showing split and formation of lips.Based on the detailed observation and statistics of microfossil materials,we propose that the genus Schizofusais the later stage of some Leiosphaeridia.