Phylogenomic Resolution of Sea Spider Diversification through Integration of Multiple Data Classes

• DOI: 10.1093/molbev/msaa228
• Publication Date: 2020-09-09T19:12:12Z
• Authors: Jesús A Ballesteros; Emily V W Setton; Carlos E Santibáñ...; Claudia P Arango; Georg Brenneis; Saskia Brix; Kevin F Corbett; Esperanza Cano-Sá...; Merai Dandouch; Geoffrey F Dilly; Marc P Eleaume; Guilherme Gainett; Cyril Gallut; Sean McAtee; Lauren McIntyre; Amy L Moran; Randy Moran; Pablo J López-Gon...; Gerhard Scholtz; Clay Williamson; H Arthur Woods; Jakob T Zehms; Ward C Wheeler; Prashant P Sharma
• Keywords: Sister group; Phylogenomics; Echinoderm

Abstract Despite significant advances in invertebrate phylogenomics over the past decade, higher-level phylogeny of Pycnogonida (sea spiders) remains elusive. Due to inaccessibility some small-bodied lineages, few phylogenetic studies have sampled all sea spider families. Previous efforts based on a handful genes yielded unstable tree topologies. Here, we inferred relationships 89 species using targeted capture mitochondrial genome, 56 conserved exons, 101 ultraconserved elements, and 3 nuclear ribosomal genes. We molecular divergence times by integrating morphological data for fossil calibrate 15 nodes arthropod life. This integration classes resolved basal topology spiders with high support. The enigmatic family Austrodecidae was as sister group remaining Rhynchothoracidae robust-bodied Pycnogonidae. Molecular time estimation recovered crown Ordovician. Comparison diversification dynamics other marine taxa that originated Paleozoic suggests crustacean groups exhibit resilience mass extinction episodes, relative mollusk echinoderm lineages.