Abstract Despite the increasing importance of molecular sequence data, morphology still makes an important contribution to resolving the phylogeny of many groups, and is the only source of data for most fossils. Most systematists sample morphological characters as broadly as possible on the principle of total evidence. However, it is not uncommon for sampling to be focused on particular aspects of anatomy, either because characters therein are believed to be more informative, or because preservation biases restrict what is available. Empirically, the optimal trees from partitions of morphological data sets often represent significantly different hypotheses of relationships. Previous work on hard-part versus soft-part characters across animal phyla revealed significant differences in about a half of sampled studies. Similarly, studies of the craniodental versus postcranial characters of vertebrates revealed significantly different trees in about one-third of cases, with the highest rates observed in non-avian dinosaurs. We test whether this is a generality here with a much larger sample of 81 published data matrices across all major dinosaur groups. Using the incongruence length difference test and two variants of the incongruence relationship difference test, we found significant incongruence in about 50% of cases. Incongruence is not uniformly distributed across major dinosaur clades, being highest (63%) in Theropoda and lowest (25%) in Thyreophora. As in previous studies, our partition tests show some sensitivity to matrix dimensions and the amount and distribution of missing entries. Levels of homoplasy and retained synapomorphy are similar between partitions, such that incongruence must partly reflect differences in patterns of homoplasy between partitions, which may itself be a function of modularity and mosaic evolution. Finally, we implement new tests to determine which partition yields trees most similar to those from the entire matrix. Despite no bias across dinosaurs overall, there are striking differences between major groups. The craniodental characters of Ornithischia and the postcranial characters of Saurischia yield trees most similar to the “total evidence” trees derived from the entire matrix. Trees from these same character partitions also tend to be most stratigraphically congruent: a mutual consilience suggesting that those partitions yield more accurate trees. [Dinosauria; homoplasy; partition homogeneity.]

中文翻译：

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非鸟类恐龙的颅齿和颅后特征通常意味着不同的树


摘要 尽管分子序列数据的重要性日益增加，形态学仍然对解决许多类群的系统发育做出了重要贡献，并且是大多数化石的唯一数据来源。大多数系统学家根据总体证据的原则尽可能广泛地对形态特征进行采样。然而，采样集中于解剖学的特定方面的情况并不少见，要么是因为其中的特征被认为提供了更多信息，要么是因为保存偏差限制了可用的内容。根据经验，形态数据集分区的最佳树通常代表显着不同的关系假设。先前对动物门的硬部分和软部分特征的研究显示，大约一半的抽样研究存在显着差异。同样，对脊椎动物的颅齿和颅后特征的研究表明，在大约三分之一的情况下，树木存在显着差异，其中在非鸟类恐龙中观察到的比例最高。我们使用涵盖所有主要恐龙类群的 81 个已发布数据矩阵的更大样本来测试这是否具有普遍性。使用不一致长度差异测试和不一致关系差异测试的两种变体，我们发现大约 50% 的情况存在显着不一致。不一致在主要恐龙进化枝中分布并不均匀，兽脚亚目中最高（63%），甲龙目中最低（25%）。与之前的研究一样，我们的分区测试显示了对矩阵维度以及缺失条目的数量和分布的一些敏感性。 分区之间的同质性和保留的共源性水平相似，因此不一致必须部分反映分区之间同质性模式的差异，这本身可能是模块化和嵌合进化的函数。最后，我们实施新的测试来确定哪个分区生成的树与整个矩阵中的树最相似。尽管恐龙总体上没有偏见，但主要群体之间存在显着差异。鸟臀目的颅齿特征和蜥臀目的颅后特征产生的树与从整个矩阵衍生的“总证据”树最相似。来自这些相同特征分区的树也往往在地层上最一致：相互的一致性表明这些分区产生更准确的树。 [恐龙；同质性；分区同质性。]