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ID:55724459
大小:1.63 MB
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时间:2020-06-01
《陕南寒武系底部保存精美的Punctatus胚胎及孵化幼体化石.pdf》由会员上传分享,免费在线阅读,更多相关内容在应用文档-天天文库。
1、微体古生物学报2O12年6月;29(2):161—169ActaMicropalaeontologicaSinica29(2):161—169;June,2012陕南寒武系底部保存精美的Punctatus胚胎及孵化幼体化石*郑亚娟李勇刘云焕郭俊锋(长安大学资源学院,西部地质资源与地质工程教育部重点实验室,西安710054)提要在陕南寒武系底部的宽川铺段不仅保存了大量的小壳化石,而且还有诸多后生动物的卵和胚胎化石。目前,大量的胚胎化石已被报道,但是对古老的后生动物早期的个体发育却鲜有报道,尽管Beng
2、tson和Yue(1977)建立了Olivooides的发育序列,但仍缺少一些重要的中间环节,而且胚胎的早期卵裂阶段还不是很清楚。因此,Olivooides和Punctatus之间的联系很难确立。本文报道了宽川铺生物群中新发现的精美的Punctatus的卵裂期、囊胚期及孵化幼体阶段的胚胎化石标本,这些新发现不仅填补了Punctatus发育序列中的空白,而且揭示了Olivooides和Punctatus之间的联系。这些新收集的Punctatus的卯裂期和孵化期的化石特征及Punctatus的形态学证明
3、了Punctatus不是浮游生物,而是底栖生物。大量的胚胎化石和Punctatus的孵化幼体化石标本为我们研究后生动物早期演化提供了线索。关键词胚胎发育序列刺细胞动物寒武纪陕西EXCEPTIoNALLYPRESERVEDEMBRYoSANDoNToGENYoFPUNCr』T吣FRoMTHELoWERMoSTCAMBRIANoFTHESoUTHERNSHAANXI,CHINAZHENGYajuan,LIYong,LIUYunhuanandGU()Junfeng(CollegeofEarthScienc
4、eandLandResources,KeyLaboratoryofWesternChina’sMineralResourcesandGeologicalEngineering,MinistryofEducation,Chang’anUniversity,Xi’an710054)AbstractInsouthShaanxi,China·thelowermostCambrian—KuanchuanpuFormationcontainsnotonlyabundantsmal1shellyfossilsbu
5、talsometazoaneggsandembryos.Knowledgeofthesefossilembryoshasincreaseddramatical—ly,butrelativelylittleinformationhasbeenreportedconcerningtheearlyontogenyofancientMetazoa.AlthoughthedevelopmentalsequenceofOlivooideshasbeenreconstructedbyBengtsonandYue(
6、1997),somecrucialdevelopmentalstagesarestillobscureandtheembryosofearlycleavagestagesareuncertain.Accordingly,ithasbeendifficulttoreconstructtherelationshipbetweenOlivooidesandPunctatus.HerewereportSOFtienewexquisitelypreservedfossilsofcleaving—stageem
7、bryos,juvenilestageandhatchedindividualsofPunctatusfromtheKuanchuanpufauna.ThesenewfindingsnotonlyfillgapsofPunctatusdevelopmentalsequence,butalsorevealtherelationshipsbetweenOlivooidesandPunctatus.AllthecharacteristicsofnewlycollectedPunctatushatching
8、sandthemorphologyofthehatchedPunctatussuggeststhatitwasnotpelagic,butratherbenthic.Theexceptionallywellpreservedembryosandhatch—lingsofPunctatusprovideimportantcluesabouttheearlyevolutionofmetazoansingenera1.Keywordsembryo,developmental
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