The complete mitogenome of a peanut worm Phascolosoma pacificum (Sipuncula, Phascolosomatida, Phascolosomatidea).

Sipuncula (peanut worms) is a traditional phylum which consists of unsegmented bilateral symmetric marine worms. Although it is accepted as a phylum, the phylogenetic position of Sipuncula has been questionable. There is lack of molecular record on Sipuncula species while morphological data is not enough to distinguish the closer relationships between Annelida and Sipuncula. In order to add more data to genomic library of sipunculan species, Phascolosoma pacificum (Keferstein, 1866) was collected from seagrass area of Chuuk lagoon/Micronesia and its complete mitochondrial genome sequenced. Furthermore, phylogenetic relationship of the phylum Sipuncula and the other Trochozoan phyla investigate due to mitochondrial protein coding genes. Although there is lack of recorded data, our results support the idea that Sipuncula are nested within Annelida according to phylogenetic analyses of mitochondrial protein coding genes.