Phylogenetics of Lepidonotopodini (Macellicephalinae, Polynoidae) and Comparative Mitogenomics of Shallow-Water vs. Deep-Sea Scaleworms (Aphroditiformia)

Within Polynoidae, a diverse aphroditiform family, the subfamily Macellicephalinae is comprised of deep-sea scaleworms. Tribe Lepidonotopodini is a clade inhabiting chemosynthetic-based environments. In this study, newly sequenced genome "skimming" data for 30 deep-sea scaleworms and comparatively shallow-living Eulagisca gigantea was used to bioinformatically assemble mitogenomes. Deep-sea scaleworms exhibited increased gene order rearrangement events and positive selection of mitochondrial genes compared to shallow-water relatives. Furthermore, inclusion of skimming data for already known Lepidonotopodini species allowed for the increased coverage in DNA data and representation of taxa necessary to create a more robust phylogeny using 18 genes, as opposed to the six genes previously used. The results showed that previously recovered non-monophyly in Lepidonotopodium and Branchinotogluma, and newly recovered in Levensteiniella, could be resolved with the erection of five new genera and emended diagnoses for Lepidonotopodium, Levensteiniella, Branchinotogluma, and Branchipolynoe.