Assis Leandro C S, Rieppel Olivier
Laboratório de Sistemática Vegetal, Departamento de Botânica, Universidade de São Paulo, Rua do Matão 277, São Paulo, SP 05508-090, Brazil.
Department of Geology, The Field Museum, 1400 S. Lake Shore Drive, Chicago, IL 60605-2496, USA.
Cladistics. 2011 Feb;27(1):94-102. doi: 10.1111/j.1096-0031.2010.00317.x.
Species are groups of organisms, marked out by reproductive (replicative) properties. Monophyletic taxa are groups of species, marked out by synapomorphies. In Nelson's analysis, monophyly and synapomorphy are identical relations. Monophyly and synapomorphy, however, are not equivalent relations. Monophyly is epistemically not accessible, whereas synapomorphy is epistemically accessible through character analysis. Monophyly originates with speciation, the two sister-species that come into being through the splitting of the ancestral species lineage forming a monophyletic taxon at the lowest level of inclusiveness. Synapomorphy provides the empirical evidence for monophyly, inferred from character analysis in the context of a three-taxon statement. If synapomorphy and monophyly were equivalent, phylogenetic systematists should find a single tree, instead of multiple equally parsimonious trees. Understanding synapomorphy as the relevant evidence for phylogenetic inference reveals a category mistake in contemporary phylogenetics: the treatment of morphological characters mapped onto molecular trees as synapomorphies and homoplasies. The mapping of morphological characters onto nodes of a molecular tree results in an empirically empty procedure for synapomorphy discovery. Morphological synapomorphies and homoplasies can only be discovered by morphological and combined analyses. The use of morphology in phylogenetic inference in general is defended by examples from Laurales and Squamata in particular. To make empirical evidence scientifically relevant in order to search for concordance, or dis-concordance, of phylogenetic signal, is certainly more fruitful for phylogenetics than the uncritical mapping of morphological traits on a molecular scaffold. © The Willi Hennig Society 2010.
物种是由生殖（复制）特性划分出来的生物群体。单系类群是由共衍征划分出来的物种群体。在纳尔逊的分析中，单系性和共衍征是同一关系。然而，单系性和共衍征并非等同关系。单系性在认知上无法获取，而共衍征可通过性状分析在认知上获取。单系性起源于物种形成，通过祖先物种谱系的分裂而产生的两个姊妹物种在最低包容水平上形成一个单系类群。共衍征为单系性提供了经验证据，它是从三分类单元陈述背景下的性状分析推断出来的。如果共衍征和单系性等同，系统发育系统学家应该找到一棵单一的树，而不是多棵同样简约的树。将共衍征理解为系统发育推断的相关证据揭示了当代系统发育学中的一个范畴错误：将映射到分子树上的形态性状视为共衍征和同形相似。将形态性状映射到分子树的节点上会导致一个在经验上发现共衍征的空洞程序。形态共衍征和同形相似只能通过形态学和综合分析来发现。一般来说，系统发育推断中形态学的运用通过特别是来自樟目和有鳞目动物的例子得到了辩护。为了使经验证据具有科学相关性以便寻找系统发育信号的一致性或不一致性，这对系统发育学来说肯定比在分子框架上不加批判地映射形态性状更有成效。©威利·亨尼希协会2010年。
