Data from: The identification of concerted convergence in insect heads corroborates Palaeoptera

The relationships of the three major clades of winged insects - Ephemeroptera, Odonata and Neoptera - are still unclear. Many morphologists favor a clade Metapterygota (Odonata+Neoptera), but Chiastomyaria (Ephemeroptera+Neoptera) or Palaeoptera (Ephemeroptera+Odonata) have also been supported in some older and more recent studies. A possible explanation for the difficulties in resolving these relationships is concerted convergence - the convergent evolution of entire character complexes under the same or similar selective pressures. In this study we analyse possible instances of this phenomenon in the context of head structures of Ephemeroptera, Odonata and Neoptera. We apply a recently introduced formal approach to detect the occurrence of concerted convergence. We found that characters of the tentorium and mandibles in particular, but also some other head structures, have apparently not evolved independently, and thus can cause artefacts in tree reconstruction. Our subsequent analyses, which exclude character sets that may be affected by concerted convergence, corroborate the Palaeoptera concept. We show that the analysis of homoplasy and its influence on tree inference can be formally improved with important consequences for the identification of incompatibilities between datasets. Our results suggest that modified weighting (or exclusion of characters) in cases of formally identified correlated cliques of characters may improve morphology based tree reconstruction.有翅昆虫三大演化支（clade）——蜉蝣目（Ephemeroptera）、蜻蜓目（Odonata）与新翅下纲（Neoptera）之间的系统发育关系至今仍未明确。尽管多数形态学家支持由蜻蜓目与新翅下纲构成的后翅亚纲（Metapterygota）演化支，但在部分早期及近期研究中，也有学者分别支持Chiastomyaria（蜉蝣目+新翅下纲）或古翅下纲（Palaeoptera，蜉蝣目+蜻蜓目）这两种假说。 目前学界对这类系统发育关系的解析存在难点，一种可行的解释为协同趋同演化（concerted convergence）——即在相同或相似选择压力（selective pressures）下，整套性状复合体（character complexes）发生趋同演化的现象。 本研究以蜉蝣目、蜻蜓目与新翅下纲的头部结构（head structures）为研究对象，分析该现象可能存在的案例，并采用新近提出的形式化方法（formal approach），检测协同趋同演化的发生情况。 研究发现，幕骨（tentorium）与上颚（mandibles）的相关性状尤为显著，此外部分其他头部结构的性状也并非独立演化，因此可能会对系统发育树重建（tree reconstruction）造成人为误差。后续我们排除了可能受协同趋同演化影响的性状集开展分析，结果支持古翅下纲（Palaeoptera）假说。本研究表明，对同塑性（homoplasy）及其对系统发育树推断（tree inference）的影响进行形式化分析，可有效优化分析流程，这对识别数据集间的不相容性具有重要价值。结果还显示，当通过形式化方法鉴定出存在关联的性状簇（cliques of characters）时，对性状进行加权调整（或直接排除受影响性状），可显著优化基于形态学数据的系统发育树重建工作。