ROOTING PHYLOGENIES OF PROBLEMATIC FOSSIL TAXA; A CASE STUDY USING CINCTANS (STEM-GROUP ECHINODERMS)
ROOTING PHYLOGENIES OF PROBLEMATIC FOSSIL TAXA; A CASE STUDY USING CINCTANS (STEM-GROUP ECHINODERMS)
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DOI：
10.1111/j.1475-4983.2009.00880.x
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发表时间：
2009-07-01
期刊：
影响因子：
2.6
通讯作者：
Zamora, Samuel
中科院分区：
文献类型：
--
作者：
Smith, Andrew B.;Zamora, Samuel
已灭绝的分支，其较高层次的关系是有问题的或有争议的构成一个特殊的问题，因为系统发育分析建立一个令人信服的根的困难。棘皮动物是原始前辐射棘皮动物的一个有问题的类群，它们的形态如此独特，以至于很少有特征能与任何其他类群有效地同源。在这里，我们使用一个两阶段的方法，首先构建一个无根网络使用的整体，其中个别板同源的遗传信息字符，然后确定根的位置与一个小得多的一组重铸字符，可以极化外群和/或个体发育的标准。此外，当生根是基于地层标准的相同的两个主要派生分支被确定，虽然基础的关系有些不同。我们认为，使用我们的各种方法获得的结果的一致性提供了信心，我们已经正确地植根于分支图。本文提出了一个新的分类系统。
Extinct clades whose higher-level relationships are problematic or disputed pose a particular problem for phylogenetic analysis because of the difficulty of establishing a convincing root. Cinctans are a problematic group of primitive preradiate echinoderms whose morphology is so distinct that few characters can be usefully homologized with any other group. Here we use a two stage approach, first constructing an unrooted network using the totality of phylogenetically informative characters in which individual plates are homologized, and then determining the root position with a much smaller set of recast characters that can be polarized by outgroup and/or ontogenetic criteria. Furthermore, when rooting is based on stratigraphic criteria the same two major derived clades are identified, although basal relationships are somewhat different. We contend that the congruence of results obtained using our various approaches provides confidence that we have correctly rooted the cladogram. A revised taxonomy for Cincta is presented.