de Bivort Benjamin L, Clouse Ronald M, Giribet Gonzalo
Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA.
Rowland Institute at Harvard, 100 Edwin Land Boulevard, Cambridge, MA 02142, USA.
Cladistics. 2012 Dec;28(6):582-597. doi: 10.1111/j.1096-0031.2012.00407.x. Epub 2012 Jul 20.
Two character sets composed of continuous measurements and shape descriptors for mite harvestmen (Arachnida, Opiliones, Cyphophthalmi) were used to reconstruct the morphology of the cyphophthalmid ancestor and explore different methods for ancestral reconstruction as well as the influence of terminal sets and phylogenetic topologies. Characters common to both data sets were used to evaluate linear parsimony, averaging, maximum likelihood and Bayesian methods on seven different phylogenies found in earlier studies. Two methods-linear parsimony implemented in TNT and nested averaging-generated reconstructions that were (i) not predisposed to comprising simple averages of characters and (ii) in broad agreement with alternative methods commonly used. Of these two methods, linear parsimony yielded significantly similar reconstructions from two independent Cyphophthalmi data sets, and exhibited comparatively low ambiguity in the values of ancestral characters. Therefore complete sets of continuous characters were optimized using linear parsimony on trees found from "total evidence" data sets. The resulting images of the ancestral Cyphophthalmi suggest it was a small animal with robust appendages and a lens-less eye, much like many of today's species, but not what might be expected from hypothetical reconstructions of Paleozoic vegetation debris, where Cyphophthalmi likely originated. © The Willi Hennig Society 2012.
由螨类盲蛛（蛛形纲，盲蛛目，微盲蛛亚目）的连续测量数据和形状描述符组成的两个字符集，被用于重建微盲蛛亚目祖先的形态，并探索祖先重建的不同方法以及终端集和系统发育拓扑结构的影响。这两个数据集共有的特征被用于评估早期研究中发现的七种不同系统发育树上的线性简约法、平均法、最大似然法和贝叶斯法。两种方法——TNT中实现的线性简约法和嵌套平均法——生成的重建结果具有以下特点：（i）不会倾向于包含简单的性状平均值；（ii）与常用的其他方法大致一致。在这两种方法中，线性简约法从两个独立的微盲蛛亚目数据集得出了显著相似的重建结果，并且在祖先性状值方面表现出相对较低的模糊性。因此，使用线性简约法在从“全证据”数据集得出的树上对完整的连续性状集进行了优化。由此得到的微盲蛛亚目祖先的图像表明，它是一种小型动物，附肢粗壮，没有晶状体眼，这与当今的许多物种很相似，但与基于古生代植被残骸的假设重建所预期的情况不同，而微盲蛛亚目很可能起源于古生代植被残骸。© 威利·亨尼格学会2012年。
