Phylogenomic analyses of Crassiclitellata support major Northern and Southern Hemisphere clades and a Pangaean origin for earthworms

Abstract

BackgroundEarthworms (Crassiclitellata) are a diverse group of annelids of substantial ecological and economic importance. Earthworms are primarily terrestrial infaunal animals, and as such are probably rather poor natural dispersers. Therefore, the near global distribution of earthworms reflects an old and likely complex evolutionary history. Despite a long-standing interest in Crassiclitellata, relationships among and within major clades remain unresolved.MethodsIn this study, we evaluate crassiclitellate phylogenetic relationships using 38 new transcriptomes in combination with publicly available transcriptome data. Our data include representatives of nearly all extant earthworm families and a representative of Moniligastridae, another terrestrial annelid group thought to be closely related to Crassiclitellata. We use a series of differentially filtered data matrices and analyses to examine the effects of data partitioning, missing data, compositional and branch-length heterogeneity, and outgroup inclusion.Results and discussionWe recover a consistent, strongly supported ingroup topology irrespective of differences in methodology. The topology supports two major earthworm clades, each of which consists of a Northern Hemisphere subclade and a Southern Hemisphere subclade. Divergence time analysis results are concordant with the hypothesis that these north-south splits are the result of the breakup of the supercontinent Pangaea.ConclusionsThese results support several recently proposed revisions to the classical understanding of earthworm phylogeny, reveal two major clades that seem to reflect Pangaean distributions, and raise new questions about earthworm evolutionary relationships.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-017-0973-4) contains supplementary material, which is available to authorized users.

Microorganization of ovaries and oogenesis of Haplotaxis sp. (Clitellata: Haplotaxidae)

“…Recent molecular analyses based on transcriptome data have shown that representatives of the Haplotaxidae sensu lato (i.e., Haplotaxis gordioides , Delaya leruthi , and Pelodrilus sp.) comprised the sister group of Metagynophora (Crassiclitellata + Moniligastridae) (Anderson et al, 2017). When more exhaustive taxonomic sampling was considered, Haplotaxidae appeared as non‐monophyletic, Pelodrilus sp.…”

“…More recent molecular analyses confirmed that Haplotaxidae are the closest relatives to Crassiclitellata, although as a paraphyletic assemblage (Anderson et al, 2017;Martinez-Ansemil, Creuzé Des Châtelliers, Martin, & Sambugar, 2012). Finally, a broad phylogenetic assessment based on transcriptomic genetic data (Erséus et al, 2020) showed that haplotaxids are not monophyletic and that some of them cluster either with Crassiclitellata or Moniligastridae (earthworm-sized terrestrial non-crassiclitellates).…”

Na+/K+‐ATPase gene duplications in clitellate annelids are associated with freshwater colonization

“…Number of species are from Sket and Trontelj (), Williams, Gelder, Proctor, and Coltman (), Anderson et al. () or estimated from Reynolds and Wetzel (). Also shown are the species from each lineage used in this study.…”

Erratum to: Phylogenomic analyses of Crassiclitellata support major Northern and Southern hemisphere clades and a Pangaean origin for earthworms

“…After publication of the original article [ 1 ], the authors received the correct museum catalogue number of Avelona ligra , Lumbricidae, which is listed in Table 1 . The museum number currently reads MNHN XXXXXX in the original article, but should read MNHN HEL593.…”