峡东区上震旦统陡山沱组发现宏体化石

DISCOVERY OF THE MACROFOSSILS IN THE UPPER SINIAN DOUSHANTUO FORMATION AT MIAOHE, EASTERN YANGTZE GORGES

峡东区上震旦统陡山沱组顶部发现宏体化石,包括高级藻类和蠕虫类,共8属10种,其中有些分类未定的化石。这从形态学上证明了后生藻类植物的分化及第一次为后生动物在陡山沱期的存在提供了可信的证据。这是一次有突破性的发现。

A new biota composed of the macrofossils in the upper Sinian deposits at Miaohe is de-scribed. None of the earlier reports on metazoan fossils from the Doushantuo Formation is compelling. In our finding, all of the metazoan fossils belongs to worm roughly, but the exact affinity is uncertain. Of them, Niuganmafeia obesa Chen, gen. et sp. nov., Jiuqunaoella sim-plicis Chen, gen. et sp. nov and Diaoyapolites longiconoidalis Chen, gen. et sp. nov are recognized. The last one is similar to Cambrorytium major (Walcott) (a Tubicolus Metazoan) from the Middle Cambrian Burgess Shale.The Carbonaceous fossils of metaphyta with mono-yor multi-bifurcation are: Enteromorphi-tes simansis Zhu et Chen, 1984, Miaohephyton bifurcatum Chen, gen. et sp. nov., and Doushan-tuophyton lineare Chen, gen et sp. nov. There some also are problematic, such as? Tawuid-type fossil,? Tyrasoiaenia sp.,? Vendotaema sp., etc. The diversification of metaphyta first became evident in Earth history. Since Archean, the prokaryotic microbial community is gradually supplanted by the primary 'submarine grassland' of the metaphyta which acted as an important factor in Sinian ecosystem, which facilitated the metazoan accelerative evolution through wave-resistance, providing shelter from preying and the nutrient-rich food etc. These algal fossils are more advanced than those reported abroad from the late Riphean or Vendian, but less than those non-calcareous algal fossils from the Middle Cambrian Burgess shale in the thallus size, times of branching, and pattern of (verticillate) branching or spine arrangement. These advanced algal forms are significant, especially as the entity of metaphyta for Vendotaenids is questioned by Vidal (1989). Furthermore, some stonecoal could be formed from the fossil algae.In a word, it is not exaggerated that this discovery is a breakthrough in Precambrian Paleontology.