Phylogenomic analyses unravel annelid evolution

  title={Phylogenomic analyses unravel annelid evolution},
  author={Torsten H. Struck and Christiane Paul and Natascha Hill and Stefanie Hartmann and Christoph H{\"o}sel and Michael Kube and Bernhard Lieb and Achim Meyer and Ralph Tiedemann and G{\"u}nter Purschke and Christoph Bleidorn},
Annelida, the ringed worms, is a highly diverse animal phylum that includes more than 15,000 described species and constitutes the dominant benthic macrofauna from the intertidal zone down to the deep sea. A robust annelid phylogeny would shape our understanding of animal body-plan evolution and shed light on the bilaterian ground pattern. Traditionally, Annelida has been split into two major groups: Clitellata (earthworms and leeches) and polychaetes (bristle worms), but recent evidence… 

Illuminating the base of the annelid tree using transcriptomics.

This study based on transcriptomic data comprising 68,750-170,497 amino acid sites from 305 to 622 proteins resolves annelid relationships, including Chaetopteridae, Amphinomidae, Sipuncula, Oweniidae, and Magelonidae in the basal part of the tree.

Phylogeny of Annelida

The phylogeny of Annelida was split into two major clades, one clade adapted to an errant mobile life and the other which includes earthworms and leeches, to a more sessile, sedentary one.

Current status of annelid phylogeny

The new annelids phylogeny highlights the variability and lability of annelid body plans, and many instances of simplifications of body plan as adaptations to new life styles can be found.

Phylogenomics resolves ambiguous relationships within Aciculata (Errantia, Annelida).

Articulating "Archiannelids": Phylogenomics and Annelid Relationships, with Emphasis on Meiofaunal Taxa.

A new Illumina-based data set is generated to address annelid relationships from a fresh perspective, independent from previously generated data and with nearly fully occupied matrices, and largely corroborate the phylogenomic results of Weigert et al. (2014).

The origin of annelids

A novel clade of machaeridians, the Cuniculepadida, is identified, which exhibit a series of adaptations for burrowing, and is identified as a convincing body of molecular evidence that polychaetes form a paraphyletic grade and that clitellates are derived polychaETes.

Recent progress in reconstructing lophotrochozoan (spiralian) phylogeny

New evidence supporting the inclusion of chaetognaths within gnathiferans, the phylogenetic position of Orthonectida and Dicyemida, as well as the general phylogeny of lophotrochozoans is reviewed.


A novel clade of machaeridians is identified, the Cuniculepadida, which exhibit a series of adaptations for burrowing, which is a convincing body of molecular evidence that polychaetes form a paraphyletic grade and that clitellates are derived polychae- tes.

The impact of fossil data on annelid phylogeny inferred from discrete morphological characters

A reinvestigation of the morphology of key fossil taxa is presented and analyses using probabilistic methods and both equal- and implied-weights parsimony recover paraphyletic polychaetes and support the conclusion that echiurans and clitellates are derived polychaETes.

Evolution of mitochondrial gene order in Annelida.




Annelid phylogeny and the status of Sipuncula and Echiura

Using multiple genes and explicit hypothesis testing, it is shown that Echiura, Siboglinidae, and Clitellata are derived annelid with polychaete sister taxa, and that Sipuncula should be included within annelids.

Phylogeny of Annelida (Lophotrochozoa): total-evidence analysis of morphology and six genes

The combined ("total-evidence") phylogenetic analysis provides a modified view of annelid evolution, with several higher-level taxa, i.e. the monophyly of the Aciculata, sister-group relationships between the Eunicida and OPC, between the Cirratuliformia and SSC, and possibly also between the "Clitellatomorpha" and Oweniidae-Pogonophora clades.

Molecular evidence that echiurans and pogonophorans are derived annelids.

  • D. McHugh
  • Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 1997
This result, indicating the derived loss of segmentation in echiurans, has profound implications for the understanding of the evolution of metazoan body plans and challenges the traditional view of the phylum-level diversity and evolutionary relationships of protostome worms.

Phylogenetic position of Sipuncula derived from multi‐gene and phylogenomic data and its implication for the evolution of segmentation

It is revealed that Sipuncula had secondarily lost segmentation, which does not support the hypothesis that the last common ancestor of Annelida, Arthropoda and Chordata was segmented, assuming several losses along the branches leading to them.

On the phylogenetic position of Myzostomida: can 77 genes get it wrong?

It is concluded that reliance of a set of markers belonging to a single class of macromolecular complexes might bias the analysis, and that concatenation of all available data might introduce conflicting signal into phylogenetic analyses.

Mitochondrial genome and nuclear sequence data support myzostomida as part of the annelid radiation.

The molecular data are in agreement with the morphological evidence that myzostomids are part of the annelid radiation and probably evolved from a segmented ancestor and gained a derived anatomy during their long evolutionary history as echinoderm symbionts.

Phylogeny of oligochaetous Clitellata

DNA sequences as well as spermatozoal ultrastructure corroborate that all leech-like taxa constitute a clade derived within ‘Oligochaeta’, closely related to the family Lumbriculidae, and refutes a recent hypothesis proposing that the ancestor of Clitellata was terrestrial.

Phylogenetic position of Nemertea derived from phylogenomic data.

Nemertea and Platyhelminthes have traditionally been grouped together because they possess a so-called acoelomate organization, but lateral vessels and rhynchocoel of nemerteans have been regarded as coelomic cavities, where Nemertea is most likely due to a secondary reduction of the coelom as it is found in certain species of Mollusca and Annelida.

Phylogenomic analyses of lophophorates (brachiopods, phoronids and bryozoans) confirm the Lophotrochozoa concept

These analyses show that the three lophophorate lineages are affiliated with trochozoan rather than deuterostome phyla, and all hypotheses claiming that they are more closely related to Deuterstomia than to Protostomia can be rejected by topology testing.

Molecular systematics of polychaetes (Annelida)

Only by expanding molecular systematic studies of polychaetes to analyses of nuclear coding genes for comprehensive taxon samples will it become clear whether the lack of basal-node resolution observed in analyses of 18S rRNA reflects a rapid radiation of the group, or is a feature associated with the 18SR rRNA gene itself.