新元古代磷酸盐化外包型腔原肠胚化石在瓮安生物群中的发现  

EPIBOLIC GASTRULA EMBRYO FOSSILS FROM THE EDIACARAN WENG’AN BIOTA (GUIZHOU,SOUTHWEST CHINA)

作　　者：殷宗军[1] 朱茂炎[1] 

机构地区：[1]现代古生物学和地层学国家重点实验室,中国科学院南京地质古生物研究所,南京210008

出　　处：《古生物学报》2010年第3期325-335,共11页Acta Palaeontologica Sinica

基　　金：中国科学院资源环境领域知识创新方向性项目(KZCX-YW-Q08-4);国家重点基础研究发展规划项目(2006CB806401);国家自然科学基金(40725005,40930211)联合资助

摘　　要：贵州瓮安埃迪卡拉纪陡山沱组(635—551Ma)上磷矿段保存了丰富的磷酸盐化动物胚胎化石,其中绝大多数为早期卵裂胚胎化石,原肠胚化石相对罕见。文中报道瓮安生物群中新发现的一种类似现代两栖动物胚胎的外包型腔原肠胚化石,并依据新的三维立体胚胎化石标本对瓮安陡山沱组原肠胚期动物化石的多样性及其可能的亲缘关系进行初步探讨,认为:1)"外包型腔原肠胚"和已有轴性分化的"外包型实体原肠胚"的发现为证明瓮安生物群中存在两侧对称动物提供了新的化石证据;2)"单极内陷型腔原肠胚"因胚体存在巨大空腔(囊胚腔和原肠腔)而难以被磷酸盐化精细保存,故在瓮安生物群中的化石记录稀少且亲缘关系不明;3)瓮安生物群中的"单极内移型腔原肠胚"和"分层型腔原肠胚"化石的可靠性尚有待更多的标本提供佐证。瓮安生物群中颇具多样性的原肠胚期动物化石为探索后生动物在晚新元古代的胚胎发育模式开拓了思路。Abundant embryo fossils from the upper Doushantuo Formation at Weng’an phosphate mining area （Guizhou Province,South China） have been considered as the earliest fossil records of multicellular animal life on Earth.However,most of these embryo fossils are at early cleavage stages,post-blastula stage ones are quite rare.Here we report probable epibolic gastrula fossils resembling living amphibian embryos from the Weng’an biota,and make a review on the diversity of the Doushantuo gastrula fossils based on new specimens.The results demonstrate that：1） Fossil gastrulae formed by epiboly and complex stereogastrulae with bilaterian features from the Weng’an biota provide new evidence for the existence of bilateral animals in the late Neoproterozoic;2） Fossil coleogastrulae formed by invagination are rare and poorly preserved;3） Fossil gastrulae formed by unipolar ingression and delamination remain uncertain.Various gastrula fossils from the Weng’an biota shed new light on the study of embryo development of multicellular animals before the Cambrian Explosion.

关 键 词：胚胎化石 瓮安生物群 陡山沱组 埃迪卡拉纪 新元古代 

分 类 号：Q915[天文地球—古生物学与地层学]