陕南新元古代末期微体管状疑难化石

末元古纪以Cloudina为代表的管状动物化石是目前世界上公认最早的具矿化骨骼的生物类群,在世界许多地区都有发现,但它并不是当时唯一的矿化生物类型,更多的动物骨骼化化石证据在寒武纪大爆发之前的沉积物中时有发现。作者在处理陕南末元古纪的化石过程中,发现了大量不同形态的微体管状化石(直径大多小于150μm),包括末端封闭的粗短管体,不分枝管体,末端扩展的骨针状构造及具多种分叉样式的分枝管体。这些化石的亲缘关系仍不清楚,但它们为我们提供了动物演化和矿化初始阶段的化石记录。

TERMINAL NEOPROTEROZOIC TUBULAR MICROPROBLEMATICA FROM THE DENGYING FORMATION, SOUTHERN SHAANXI

Cloudina was known as the first animal acquired mineralized skeleton at the terminal Neoproterozoic,but it was not the only exception that could secret minerals. More evidence of diverse skeletal animals came from deposits before the Cambrian"big bang". A relatively diverse tubular microfossil assemblage is described from the Terminal Neoproterozoic Dengying Formation of South Shaanxi, China. All specimens are of small size, mostly less than 150 μm in diameter. In gross morphology, those problematical microfossils consist of stout tubes with closed base, tiny internal mold of elongated tube, parallel clustered unbranching tubes, spicule-like structure with expanded circular base, and branching tubes of various bifurcating styles. Their affinities are still unclear, but they may provide a critical new dimension to the record of the initial phase of animal evolution and biomineralization.