Updated phylogeny of Vestimentifera (Siboglinidae, Polychaeta, Annelida) based on mitochondrial genomes, with a new species.

ABSTRACT

Siboglinid tubeworms are found at chemosynthetic environments worldwide and the Vestimentifera clade is particularly well known for their reliance on chemoautotrophic bacterial symbionts for nutrition. The mitochondrial genomes have been published for nine vestimentiferan species to date. This study provides new complete mitochondrial genomes for ten further Vestimentifera, including the first mitochondrial genomes sequenced for Alaysia spiralis, Arcovestia ivanovi, Lamellibrachia barhami, Lamellibrachia columna, Lamellibrachia donwalshi, and unnamed species of Alaysia and Oasisia. Phylogenetic analyses combining fifteen mitochondrial genes and the nuclear 18S rRNA gene recovered Lamellibrachia as sister to the remaining Vestimentifera and Riftia pachyptila as separate from the other vent-endemic taxa. Implications and auxiliary analyses regarding differing phylogenetic tree topologies, substitution saturation, ancestral state reconstruction, and divergence estimates are also discussed. Additionally, a new species of Alaysia is described from the Manus Basin.