Meeting Abstract
Deep-sea tubeworms (Annelid, Siboglinidae) have drawn considerable interest in ecology and evolutionary biology. As adults, they lack a digestive tract and rely on endosymbionts for nutrition. Moreover, they are important members of chemosynthetic communities such as hydrothermal vents, cold seeps, muddy sediments and whale bones. Four lineages within Siboglinidae have been recognized: Frenulata, Vestimentifera, Sclerolinum and Osedax. Despite their importance, evolutionary history within this family has been debated due to conflicting results from morphological and molecular phylogenetic studies. In particular, placement of the bone-eating Osedax worms has been unclear mainly due to their distinctive biology, including harboring heterotrophic bacteria as endosymbionts, displaying marked sexual dimorphism and exhibiting a distinct body-plan. Here, we reconstruct siboglinid phylogeny using two phylogenomic datasets: one contained 553 nuclear genes (on average 75% genes were sampled per taxa) while the other possessed 186 nuclear genes (strict dataset, on average 93.3% genes were sampled per taxa). Both datasets strongly supported Osedax being most closely related to the Vestimentifera+Sclerolinum clade, rather than the Frenulata, as previously reported. Additionally, several species-tree approaches were also conducted in order to evaluate the effects of gene incongruence when inferring phylogeny from large concatenated datasets.
