Ancestral State Reconstruction morphological data, pruned phylogeny, and full results of the phylogenetic signal tests.

Morphology has long been used to classify and identify living organisms. However, taxonomic descriptions are often limited to qualitative descriptions of size and shape, making identification difficult due to the subjective language used to describe complex shapes. Additionally, for some taxa, there are few reliable qualitative characters available for delimitation that have yet to be tested objectively in a phylogenetic context. Solifugae is one such example. The order, Solifugae, are recognized from the other arachnid orders by the possession large, powerful jaws or chelicerae. Male cheliceral morphology is the leading diagnostic character system in solifuge systematics and is the basis for much of solifuge current taxonomy. Female chelicerae, on the other hand, are reportedly deeply conserved and much of the species identification is based on female operculum morphology. Such structures can vary across multiple taxonomic levels; however, taxonomic descriptions are often restricted to qualitative descriptions of size and complex shapes. To elucidate patterns of chelicerae and opercula trait evolution within the solifuge family, Eremobatidae, we used a 2-dimenstional (2D) morphological analysis using an Elliptical Fourier (EF) approach for closed outlines, in addition to an analysis of traditionally used measures in a phylogenetic context. Using ancestral state reconstruction (ASR) and ultra-conserved elements (UCEs), we assessed the taxonomic utility of female cheliceral and opercular morphology, and we evaluated which male morphological characters reflect shared, derived ancestry. Investigation into ubiquitously used character sets, in addition to newly proposed characters herein, illustrates the complex evolution of traits with high levels of convergence. Our results, provide taxonomic insight into future, higher level taxonomic revisions of Eremobatidae.

形态学长期以来被广泛应用于生物的分类与物种鉴定。然而，分类学描述往往仅局限于对体型与形态的定性描述，而用于描述复杂形态的语言具有主观性，这使得物种鉴定难度陡增。此外，对于部分类群而言，可用于类群界定的可靠定性性状寥寥无几，且尚未在系统发育框架下开展客观检验。避日蛛目（Solifugae）便是此类类群之一：其区别于其他蛛形纲类群的典型特征为拥有硕大且强劲的颚部或螯肢（chelicerae）。雄性螯肢形态学是避日蛛分类学研究中首要的鉴定性状体系，也是当前绝大多数避日蛛类群分类的核心依据；而雌性螯肢则被认为具有高度保守性，目前多数物种鉴定工作均基于雌性生殖盖（operculum）的形态特征。此类结构在不同分类层级中均存在变异，但分类学描述往往仍仅局限于对其体型与复杂形态的定性描述。为阐明避日蛛科（Eremobatidae）内螯肢与生殖盖的性状演化模式，本研究采用针对闭合轮廓的椭圆傅里叶（Elliptical Fourier, EF）分析方法开展二维形态学分析，并结合系统发育框架对传统形态测量指标进行分析。本研究借助祖先状态重建（Ancestral State Reconstruction, ASR）技术与超保守元件（Ultra-Conserved Elements, UCEs）数据，评估了雌性螯肢与生殖盖形态的分类学应用价值，并筛选出能够反映类群共有衍征的雄性形态性状。通过对当前通用的性状体系及本文新增提出的性状展开分析，本研究揭示了高度趋同演化性状的复杂演化路径。本研究结果可为未来避日蛛科的高阶分类修订提供分类学参考依据。