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Dryad

Major revisions in pancrustacean phylogeny and evidence of sensitivity to taxon sampling

Bernot, James P1; Owen, Christopher L2; Wolfe, Joanna M3; Meland, Kenneth4; Olesen, Jørgen5; Crandall, Keith A6

Published Nov 17, 2022; Updated Apr 04, 2023 on Dryad. https://doi.org/10.5061/dryad.dr7sqvb2h

Data files

Nov 17, 2022 version files 21.71 MB
Mar 20, 2023 version files 24.99 MB
Apr 05, 2023 version files 223.50 MB
Apr 04, 2023 version files 234.60 MB

Abstract

Abstract The clade Pancrustacea, comprising crustaceans and hexapods, is the most diverse group of animals on earth, containing over 80% of animal species and half of animal biomass. It has been the subject of several recent phylogenomic analyses, yet relationships within Pancrustacea show a notable lack of stability. Here, the phylogeny is estimated with expanded taxon sampling, particularly of malacostracans. We show small changes in taxon sampling have large impacts on phylogenetic estimation. By analyzing identical orthologs between two slightly different taxon sets, we show that the differences in the resulting topologies are due primarily to the effects of taxon sampling on the phylogenetic reconstruction method. We compare trees resulting from our phylogenomic analyses with those from the literature to explore the large tree space of pancrustacean phylogenetic hypotheses and find that statistical topology tests reject the previously published trees in favor of the maximum likelihood trees produced here. Our results reject several clades including Caridoida, Eucarida, Multicrustacea, Vericrustacea, and Syncarida. Notably, we find Copepoda nested within Allotriocarida with high support and recover a novel relationship between decapods, euphausiids, and syncarids that we refer to as the Syneucarida. With denser taxon sampling, we find Stomatopoda sister to this latter clade, which we collectively name Stomatocarida, dividing Malacostraca into three clades: Leptostraca, Peracarida, and Stomatocarida. A new Bayesian divergence time estimation is conducted using 13 vetted fossils. We review our results in the context of other pancrustacean phylogenetic hypotheses and highlight 15 key taxa to sample in future studies.