High utility of Ultraconserved Elements (UCE) for disentangling the elusive relationships of tarantulas

Although tarantulas are a widespread, highly diversified, and charismatic spider group, our understanding of their evolution remains limited. A recent transcriptome-based approach, including 16% of the nominal tarantula genera (25), provided the first robust phylogenetic hypothesis of deep tarantula relationships. However, transcriptomics has practical downsides, making it less than ideal for phylogenomic analyses. Ultraconserved Elements (UCE) sequencing, a cost-effective alternative, allows for the simultaneous reading of hundreds of loci and utilizing samples with degraded DNA, including museum material, but its utility for resolving deep tarantula relationships remains to be tested. In this study, I recovered up to similar to 850 unique UCE loci from publicly available individual tarantula transcriptomes. Phylogenetic estimation using these loci resulted in topologies identical to those obtained from the published complete transcriptomic datasets, with limited phylogenetic uncertainty restricted to two branches in the tarantula tree of life. I conclude that UCE information has great potential for resolving at least moderate to deep tarantula relationships and that numerous UCE loci can be harvested from tarantula transcriptomic data. Finally, I provide databases of transcripts and UCE loci for the 27 currently available tarantula genera, facilitating their inclusion in future phylogenomic studies with deeper taxon coverage.