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Solifugae, an order of Arachnida, comprises over 1,100 species distributed in arid and semi-arid environments across the world. Understandings of solifuge basic biology is still nascent, and systematic hypotheses and subsequent taxonomic structures for groups at the family, genus, and species level are underdeveloped. Eremobatidae, which is distributed in the western United States, is one of the largest families with one of the largest publication records yet remains taxonomically troublesome given conserved morphology and extensive homoplasy. Here, I leveraged newly generated ultraconserved elements (UCEs) generated from 203 fresh collected and historical museum samples to provide representation for the majority Eremobates and Eremocosta, most of Eremorhax, and all of Eremothera, as well as outgroup members of Ammotrechidae. These, combined with the UCE libraries previously generated for Chanbria, Eremochelis, Hemerotrecha, and Horribates by Dr. Erika Garcia, are used to generate a family-level phylogenomic hypothesis for Eremobatidae, and explore their biogeographic history in the context of this hypothesis. We also take the opportunity to explore the impact of specimen quality on phylogenetic inference, explore sources of topological instability, and propose solutions for dataset with large amounts of missing data. Phylogenetic analyses produce topologies that are largely consistent with the previous work of Dr. Garcia in regards to Chanbria, Eremochelis, Hemerotrecha, and Horribates, though the topology of the earliest diverging lineages remains troublesome. Taxonomically, Eremobates is paraphyletic with respect to the placements of Eremorhax and Eremothera but is topologically consistent with the exception of a clade of E. palpisetulosus species group taxa distributed in the Chihuahuan Desert. Ancestral range estimation of the family indicates that the age of Eremobatidae predates the formation of modern-day deserts and grasslands, but cladogenesis appears to have co-occurred with the aridification of western North America, with some of the most recently diverged clades having recently expanded into cold deserts and the eastern Prairies.
As part of rectifying the paraphyly of Eremobates, I revive the genus Eremospina Roewer to accommodate a clade of México-distributed solifuges using a combination of morphometrics and UCE analyses. Within Eremospina, I place E. acuitlapanensis, E. azteca, E. fusca, E. minamoritaana, and resurrect E. tolteca from nomen dubium to take senior synonym to Eremobates durangonus, Eremorhax montezuma and Eremobates hystrix. I employed mitochondrial DNA, siphoned from UCE by-catch, to find a putative new representation of the female of E. fusca, which contrasts with the hypothesis proposed by Muma. I also describe three species new to science: Eremospina mixteca, Eremospina ngiwa, and Eremospina tachi. Lastly, I provide a dichotomous key for the identification of male and female Eremospina taxa.