Abstract
The atypoid mygalomorphs include spiders from three described families that build a diverse array of entrance web constructs, including funnel-and-sheet webs, purse webs, trapdoors, turrets and silken collars. Molecular phylogenetic analyses have generally supported the monophyly of Atypoidea, but prior studies have not sampled all relevant taxa. Here we generated a dataset of ultraconserved element loci for all described atypoid genera, including taxa (Mecicobothrium and Hexurella) key to understanding familial monophyly, divergence times, and patterns of entrance web evolution. We show that the conserved regions of the arachnid UCE probe set target exons, such that it should be possible to combine UCE and transcriptome datasets in arachnids. We also show that different UCE probes sometimes target the same protein, and under the matching parameters used here show that UCE alignments sometimes include non-orthologs. Using multiple curated phylogenomic matrices we recover a monophyletic Atypoidea, and reveal that the family Mecicobothriidae comprises four separate and divergent lineages. Fossil-calibrated divergence time analyses suggest ancient Triassic (or older) origins for several relictual atypoid lineages, with late Cretaceous/early Tertiary divergences within some genera indicating a high potential for cryptic species diversity. The ancestral entrance web construct for atypoids, and all mygalomorphs, is reconstructed as a funnel-and-sheet web.
Highlights
Phylogenetic evidence overwhelmingly indicates that the mygalomorph spiders, including trapdoor spiders and their kin, are divided into the primary clades AvicularioideaHow to cite this article Hedin M, Derkarabetian S, Alfaro A, Ramírez MJ, Bond JE. 2019
Using an annotated ultraconserved elements (UCEs) locus set with BLAST evidence for gene function and orthology, we demonstrate that Atypoidea is monophyletic, while revealing multiple cases of non-monophyly within described families
We highlight Mecicobothrium— we are confident in the results presented here, future studies with fresh specimens should verify the phylogenetic placement discussed below
Summary
Phylogenetic evidence overwhelmingly indicates that the mygalomorph spiders, including trapdoor spiders and their kin, are divided into the primary clades AvicularioideaHow to cite this article Hedin M, Derkarabetian S, Alfaro A, Ramírez MJ, Bond JE. 2019. Atypoidea was first suggested refuted by morphology, supported by few-gene molecular studies, and is seemingly confirmed by phylogenomic approaches This clade, sometimes referred to as the ‘‘atypical tarantulas’’ (Gertsch, 1949), includes three described families (Antrodiaetidae, Atypidae, Mecicobothriidae) whose members possess dorsal abdominal tergites Adult male atypoids possess a palpus with a conductor, females have bipartite spermathecal organs, and members of both sexes typically possess six spinnerets (Eskov & Zonstein, 1990) This clade is relatively ancient, as multiple fossil genera placed within the three described families are known from the Lower Cretaceous (100–112 MYA) of Mongolia (Eskov & Zonstein, 1990). Dalla Vecchia & Selden (2013) placed the Triassic (210–215 MYA) Friularachne into Atypoidea, but left the family-level placement unspecified
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