CAMEL SPIDER TRAIT EVOLUTION DEMONSTRATES REPEATED PATTERNS OF CONVERGENCE OF TAXONOMIC CHARACTERS (ARACHNIDA: SOLIFUGAE: EREMOBATIDAE)
The arachnid order, Solifugae, are recognized from the other arachnid orders by the possession large, powerful jaws or chelicerae. Chelicerae functionally serve both males and females for a variety of shared biological functionalities, however, despite some overlapping utility in both sexes, chelicerae are sexually dimorphic. 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. Limiting shape descriptions to a single qualitative descriptor excludes the consideration for variation that may exist within genera, or between populations of the same species. To elucidate patterns of chelicerae and opercula trait evolution within solifuges (Arachnida: Solifugae: 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 utility of female cheliceral and opercular morphology, and we evaluated which male morphological characters reflect shared, derived ancestry. Our updated phylogenomic hypothesis supports the previous phylogenetic hypothesis such that the most speciose genera, Eremochelis, Hemerotrecha, and Eremobates were recovered as polypheletic, thus a major revision of eremobatid taxa at the generic level should be prioritized. Investigation into ubiquitously used character sets, in addition to newly proposed characters herein, illustrates a complex evolution of traits with high levels of convergence. Our results, nonetheless, provide taxonomic insight into future, higher level taxonomic revisions of Eremobatidae.