Annelida is one of three animal groups possessing segmentation and is central in considerations about the evolution of different character traits. It has even been proposed that the bilaterian ancestor resembled an annelid. However, a robust phylogeny of Annelida, especially with respect to the basal relationships, has been lacking. Our study based on transcriptomic data comprising 68,750 – 170,497 amino acid sites from 305 – 622 proteins resolves annelid relationships, including Chaetopteridae, Amphinomidae, Sipuncula, Oweniidae, Magelonidae in the basal part of the tree. Myzostomida, which have been indicated to belong to the basal radiation as well, are now found deeply nested within Annelida as sister group to Errantia in most analyses. Based on our reconstruction of a robust annelid phylogeny, we show that the basal branching taxa include a huge variety of life-styles such as tube-dwelling and deposit-feeding, endobenthic and burrowing, tubicolous and filter-feeding, as well as errant and carnivorous forms. Ancestral character state reconstruction suggests that the ancestral annelid possessed a pair of either sensory or grooved palps, bicellular eyes, biramous parapodia bearing simple chaeta and lacked nuchal organs. Since the oldest fossil of Annelida is reported for Sipuncula (520 Mya), we infer that the early diversification of annelids took place at least in the Lower Cambrian.
Alignment_Dataset_72-2
Alignment of the dataset comprising 72 taxa with MARE α=2 applied
Dataset_72-2.fas
Alignment_Dataset_77-1.5
Alignment of the dataset comprising 77 taxa with MARE α=1.5 applied.
Dataset_77-1.5.fas
Alignment_Dataset_77-1
Alignment of the dataset comprising 77 taxa with MARE α=1 applied.
Dataset_77-1.fas
Alignment_Dataset_77-2
Alignment of the dataset comprising 77 taxa with MARE α=2 applied.
Dataset_77-2.fas
Alignment_Dataset_79-1.5
Alignment of the dataset comprising 79 taxa with MARE α=1.5 applied.
Dataset_79-1.5.fas
Alignment_Dataset_79-1
Alignment of the dataset comprising 79 taxa with MARE α=1 applied.
Dataset_79-1.fas
Alignment_Dataset_79-2
Alignment of the dataset comprising 79 taxa with MARE α=2 applied.
Dataset_79-2.fas
Supplementary File S1_Amphinomida within Errantia
Plot of psL of each constrained analysis in comparison to the best tree
Supplementary File S2_Chaetopteridae and Magelona within Sedentaria
Plot of psL of each constrained analysis in comparison to the best tree
Supplementary File S3_Chaetopteridae within Sedentaria
Plot of psL of each constrained analysis in comparison to the best tree
Supplementary File S4_Magelona and Oweniidae within Sedentaria
Plot of psL of each constrained analysis in comparison to the best tree
Supplementary File S5_Oweniidae and Chaetopteridae within Sedentaria
Plot of psL of each constrained analysis in comparison to the best tree
Supplementary File S6_Magelona within Sedentaria
Plot of psL of each constrained analysis in comparison to the best tree
Supplementary File S7_Oweniidae and Chaetopteridae within Sedentaria
Plot of psL of each constrained analysis in comparison to the best tree
Supplementary File S8_Oweniidae within Sedentaria
Plot of psL of each constrained analysis in comparison to the best tree
Supplementary File S9_Sipuncula outside Annelida
Plot of psL of each constrained analysis in comparison to the best tree
Supplementary Files S10_MorphologicalMatrix_Likelihood
Morphological matrix of the ancestral reconstruction using the likelihood criterion.
Supplementary Files S11_MorphologicalMatrix_Parsimony
Morphological matrix of the ancestral reconstruction using the parsimony criterion.
lophotrochozoa_hmmer3.tar
Core-ortholog set used for orthology prediction with HaMStR. The set was generated using proteomes from seven primer taxa (Helobdella robusta, Capitella teleta, Lottia gigantea, Schistosoma mansoni, Daphnia pulex, Apis mellifera and Caenorhabditis elegans) and comprises 2,33 orthologous genes.