PHYLOGENETIC AND STRATIGRAPHIC ANALYSIS OF EARLIEST PALEOCENE BISERIAL AND TRISERIAL PLANKTONIC-FORAMINIFERA
PHYLOGENETIC AND STRATIGRAPHIC ANALYSIS OF EARLIEST PALEOCENE BISERIAL AND TRISERIAL PLANKTONIC-FORAMINIFERA
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DOI：
10.2113/gsjfr.21.2.168
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发表时间：
1991-04-01
影响因子：
1.1
通讯作者：
DHONDT, SL
中科院分区：
文献类型：
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作者：
DHONDT, SL
古新世早期的古生有孔虫属Guembelitria、Woodringina和Chiloguembelina有几种不同的系统发育模式。 由于不同的分类学概念，形态收敛的可能性，以及普遍缺乏高分辨率的地层记录，这些类群之间的进化关系一直难以确定，本研究使用形态数据的系统发育分析，以测试最简约的分支图对应于以前建议的这些群体的亲缘关系。 结果表明，这些属构成了一个单系或并系群，与双翅目Woodringina spp。和Chiloguembelina spp.与三系Guembelitria spp.比双螺旋异螺旋属（Heterohelix spp.） 此外，Chiloguembelina spp.与Woodringina spp.比Guembelitria spp. 每个分支图详细的生物地层数据的比较不挑战这种系统发育的解释，因为分析的字符状态的地层记录是一致的所有检查系统发育假说。 最简约的分支图中存在明显的特征状态反转，这可以解释为双列型有孔虫成虫趋同进化的证据。 或者，这种明显的逆转可能表明，无论是一个字符的状态被编码为bisbrachial在本研究的背景下，或其他几个字符的状态被错误地编码，迫使一个不正确的分支图topology.Within这guembelitriid/chiloguembelinid组，起源率和分类丰富度的峰值紧随其后的bisbrachious第三纪边界。 试图对所研究的类群进行分类或对古新世有孔虫多样性进行建模，应明确认识到这一群体最早的古新世物种丰富度，以及chiloguembelinid物种可能来自guembelitriid祖先。
Several different phylogenetic schemes have been proposed for the early Paleocene planktonic foraminiferal genera Guembelitria, Woodringina, and Chiloguembelina. Evolutionary relationships within and between these taxa have been difficult to ascertain because of differing taxonomic concepts, the possibility of morphologic convergence, and a general absence of high resolution stratigraphic records.This study uses phylogenetic analysis of morphologic data in order to test the most parsimonious cladograms corresponding to previously suggested phylogenies for these groups. Results indicate that these genera constitute a monophyletic or paraphyletic group, with biserial Woodringina spp. and Chiloguembelina spp. more closely related to triserial Guembelitria spp. than to biserial Heterohelix spp. In addition, it appears that Chiloguembelina spp. are more closely related to Woodringina spp. than to Guembelitria spp. Comparison of each cladogram to detailed biostratigraphic datums does not challenge this phylogenetic interpretation because the stratigraphic record of the analyzed character states is consistent with all examined phylogenetic hypotheses. The presence of an apparent character state reversal in the most parsimonious cladogram may be interpreted as evidence for convergent evolution of adult biseriality in planktonic foraminifera. Alternatively, this apparent reversal may indicate either that more one character state is coded as biserial within the context of this study or that several other character states are incorrectly coded, forcing an incorrect cladogram topology.Within this guembelitriid/chiloguembelinid group, origination rates and taxonomic richness peak immediately following the Cretaceous-Tertiary boundary. Attempts to classify the examined taxa or to model Paleocene foraminiferal diversity should explicity recognize the earliest Paleocene species richness of this group and the probable derivation of chiloguembelinid species from a guembelitriid ancestor.