摘要
金玉玕等(Jinet al.,2001,2002)终于同意将乐平统的底界放在蓬莱滩剖面6k的底,这与王成源(Wang,1999,2000a,b,2001a-c)提出的点位完全一致,将乐平统底界放在6j或6i upper的观点都不得不放弃。这确实是一个很大的进步。但是,Henderson和Mei(2001)为维护他们提出的以Clarkina postbitteri作为乐平统底界定义的观点,又将Clarkina postbitteri分成两个亚种。Clarkina postbitteri postbitteri Henderson and Mei,2001(Per-mophiles,38:36),不符国际动物命名法规,种名无效。提出的新定义Clarkina postbitteri postbitteriMei and Wardlaw1994,是一典型的地层亚种,它包括了一部分典型的Clarkina dukouensis(Jinet al.,2001,plate1,Figs.4a,b),也不能用作乐平统底界的定义。我们应当保留Clarkina postbitteri和C.dukouensis原来的定义。Wang(2000a,plate2,figs.1-8)图示的标本肯定是Clarkina dukouensis。金玉?等(Jinet al.,2000)改变Clarkinadukouensis的首现点位,有时在7d(Permophile,38:34,fig.1,2001),有时在7e(Jinet al.,Permophile,39:38,2001)。Clarkina dukouensis的首现位置(FAD)就在6k。7b已属Clarkinaleveni带。Clarkina postbitteri可区分出三个不同的形态型而不是两个不同的亚种。Clarkina postbitteri的起源仍然不清。Mesogondolella(=Jinogo-ndolella)granti不是Clarkina postbitteri的先驱种。
Jin et al. （2001,2002） agree to place the basal boundary of the Lopingian at the base of Bed 6k of the Penglaitan section, exactly same point as Wang （1999, 2000a,b, 2001a-c） proposed. This is really a great progress. But Henderson and Mei＇s new subspecies, Clarkina postbitteri postbitteri Henderson and Mei, 2001 （Permophiles, 38 36）, is an invalid name. Subspecies of Clarkina postbitteri postbitteri Mei and Wardlaw 1994 may not be used in the definition of the base of the Lopingian. We should keep the original diagnosis of C. postbitteri and C. dukouensis. The specimens illustrated by Wang （2000a, plate 2, figures 1-8） are definitely Clarkina dukouensis. The FAD of Clarkina dukouensis is at Bed 6k. Clarkina postbitteri could be discriminated by at least three different morphotypes rather than different two subspecies. The origin of Clarkina postbitteri is still unclear. Mesogondolella （=Jinogondolella） granti is not the ancestor of Clarkina postbitteri. Bed 7b belongs to Clarkina leveni Zone.
出处
《微体古生物学报》
CSCD
北大核心
2007年第3期320-329,共10页
Acta Micropalaeontologica Sinica
基金
国家自然科学基金委员会的资助(晚二叠世牙形刺序列与地质年表
编号49272078)
