Phylogenetic systematics and evolution of the spider infraorder Mygalomorphae using genomic scale data

Abstract

26The Infraorder Mygalomorphae is one of the three main lineages of spiders comprising over 27 3,000 nominal species. This ancient group has a world-wide distribution that includes among its 28 ranks large and charismatic taxa such as tarantulas, trapdoor spiders, and highly venomous 29 funnel web spiders. Based on past molecular studies using Sanger-sequencing approaches, 30 numerous mygalomorph families (e.g., Hexathelidae, Ctenizidae, Cyrtaucheniidae, Dipluridae 31 and Nemesiidae) have been identified as non-monophyletic. However, these data were unable to 32 sufficiently resolve the higher-level (intra-and interfamilial) relationships such that the 33 necessary changes in classification could be made with confidence. Here we present a 34 comprehensive phylogenomic treatment of the spider infraorder Mygalomorphae. We employ 35 472 loci obtained through Anchored Hybrid Enrichment to reconstruct relationships among all 36 the mygalomorph spider families and estimate the timeframe of their diversification. We 37 sampled all currently recognized families, which has allowed us to assess their status, and as a 38 result, propose a new classification scheme. Our generic-level sampling has also provided an 39 evolutionary framework for revisiting questions regarding silk use in mygalomorph spiders. The 40 first such analysis for the group within a strict phylogenetic framework shows that a sheet web is 41 likely the plesiomorphic condition for mygalomorphs, as well as providing hints to the ancestral 42 foraging behavior for all spiders. Our divergence time estimates, concomitant with detailed 43 biogeographic analysis, suggest that both ancient continental-level vicariance and more recent 44 dispersal events have played an important role in shaping modern day distributional patterns. 45Based on our results, we relimit the generic composition of the Ctenizidae, Cyrtaucheniidae, 46Dipluridae and Nemesiidae. We also elevate five subfamilies to family rank: Anamidae (NEW 47 PHYLOGENY OF MYGALOMORPH SPIDERS 3 RANK), Euagridae (NEW RANK), Ischnothelidae (NEW RANK), Pycnothelidae (NEW 48 RANK), and Bemmeridae (NEW RANK). The three families Entypesidae (NEW FAMILY), 49 Microhexuridae (NEW FAMILY), and Stasimopidae (NEW FAMILY) are newly proposed. 50 Such a major rearrangement in classification, recognizing eight newly established family-level 51 rank taxa, is the largest the group has seen in over three decades since Raven's (1985) taxonomic 52 treatment. 53 54

Phylogenomic analysis and revised classification of atypoid mygalomorph spiders (Araneae, Mygalomorphae), with notes on arachnid ultraconserved element loci

“…For all three calibrations we used a maximum age of 390 MYA, corresponding to the age of fossil Uraraneida, the putative sister group of spiders (Selden, Shear & Sutton, 2008). This approximate age is in accord with maximum dates derived from other molecular clock analyses of spiders (Ayoub et al, 2007; Wood et al, 2012; Starrett et al, 2013; Fernández et al, 2018; Opatova et al, 2019).…”

“…Early-diverging atypoid lineages are often species-poor (approximating monotypic) and use silk to build funnel-and-sheet webs, while more diverse silken constructs have evolved in derived atypoid lineages. Similar patterns of species and web diversification occur in parallel in the avicularioids (Opatova et al, 2019).…”

“…Only Mecicobothrium, Calommata and Atypus were represented by single specimens (Table S1). To confirm atypoid monophyly we sampled a handful of representative avicularioid taxa, including genera representing multiple early-diverging avicularioid lineages (Bond et al, 2012; Hedin et al, 2018a; Opatova et al, 2019). Mygalomorphs are sisters to araneomorph spiders—we used an early-diverging araneomorph lineage ( Hypochilus ) to root trees.…”

“…Phylogenetic evidence now overwhelmingly indicates that the mygalomorph spiders, including trapdoor spiders and their kin, are divided into the primary clades Avicularioidea and Atypoidea (Hedin & Bond, 2006; Bond et al, 2012; Hamilton et al, 2016; Garrison et al, 2016; Wheeler et al, 2017; Hedin et al, 2018a; Fernández et al, 2018; Opatova et al, 2019). Avicularioidea includes the most familiar mygalomorphs (e.g., tarantulas), and the bulk of known taxonomic diversity (World Spider Catalog, 2019).…”

“…Avicularioidea includes the most familiar mygalomorphs (e.g., tarantulas), and the bulk of known taxonomic diversity (World Spider Catalog, 2019). Phylogenomic analyses based on sequence-capture data have now dramatically changed our understanding of family-level diversity and interrelationships within the avicularioids (Hamilton et al, 2016; Hedin et al, 2018a; Opatova et al, 2019), with many families previously suspected of non-monophyly now known to constitute multiple independent lineages (Hedin et al, 2018a; Opatova et al, 2019).…”