陕西省宁强县早寒武世宽川铺组具瘤突装饰的Olivooides-like胚胎化石新类型

早寒武世梅树村期小壳化石处于＂寒武纪生命大爆发＂的第一幕,对于揭示后生动物起源至关重要。对陕南宽川铺地区早寒武世早期宽川铺组第一个小壳化石组合带中发现的动物球状胚胎化石进行大量观察,发现了两枚Olivooides-like的新型动物胚胎化石。此类化石的胚胎表面并非Punctatus Emeiensis常见的密集分布的典型或非典型的尖刺状结构,而是呈基端具螺旋状环褶、末端较圆滑的锥状突起。新型动物卵的发现暗示了早寒武世梅树村期动物化石卵的多样性很可能发端于新元古代埃迪卡拉纪。

New Olivooides-like Embryos with Protuberances from the Early Cambrian Kuanchuanpu Formation in Ningqiang County,Shaanxi Province

The Cambrian small shelly fossils,which were diversified from the first episode of Cambrian life＇s explosion（Meishucunian Stage） in South China,were critical for understanding the origin of metazoans.Two specimens,which were the new types of Olivooids-like fossilized animal embryos,were recognized from a large amount of globular fossils at the first assemblage zone of Cambrian small shelly fossils from the Early Cambrian Kuanchuanpu Formation in Kuanchuanpu Region of Ningqiang County,Shaanxi Province.The embryos were characterized by numerous cone-like protuberances with spiral folds at the proximal part and distal smooth top end just beneath the egg shell,and remarkably different from those of typical or non-typical stellate spines of Punctatus Emeiensis.The diversity of eggs and embryos presented at the Meishucunian Stage were most likely rooted in the Neoproterozoic Ediaranian.