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（Morphology）长期以来被应用于生物的分类与物种鉴定。然而，当前的分类学描述往往仅局限于对体型与形态的定性描述，加之用于描述复杂形态的语言主观性较强，导致物种鉴定难度大幅提升。此外，部分类群仅拥有少量可靠的定性分类性状，且这些性状尚未在系统发育框架下得到客观验证。避日蛛目（Solifugae）便是其中典型案例。该目类群凭借其硕大强健的颚肢（chelicerae），可与其他蛛形纲目级类群相区分。雄性螯肢形态是避日蛛目分类学中首要的鉴定性状系统，也是当前多数避日蛛类群分类的核心依据。与之相对，雌性螯肢据报道具有高度保守性，多数物种鉴定工作依托雌性生殖盖（operculum）形态展开。这类结构在多个分类层级上均存在变异，但相关分类学描述仍常局限于对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（2D）形态学分析，并结合系统发育框架下的传统形态测量分析。本研究借助祖先状态重建（Ancestral State Reconstruction, ASR）与超保守元件（Ultra-Conserved Elements, UCEs）技术，评估了雌性螯肢与生殖盖形态的分类学应用价值，并验证了哪些雄性形态性状能够反映类群共有的衍生祖先特征。针对本研究中常规使用的性状集与新提出的性状展开的调查，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层面的参考依据。