The complete mitochondrial genome sequence of Southwellina hispida supports monophyly of Palaeacanthocephala (Acanthocephala: Polymorphida).

ABSTRACT

Acanthocephala is a relatively small, but distinct obligate parasitic group that includes 4 classes Archiacanthocephala, Palaeacanthocephala, Polyacanthocephala, and Eoacanthocephala. The phylogenetic relationships of acanthocephalans are mainly based on nuclear ribosomal genes. In this study, we determined the complete mitochondrial genome sequence of Southwellina hispida (Palaeacanthocephala Polymorphida), and used this genome sequence along with other platyzoan species (including syndermatan groups) to assess its phylogenetic position within Acanthocephala. The S. hispida mtDNA is a 14,742 bp circular molecule that contains 36 genes (lacking atp8) encoded in the same direction. Phylogenetic analyses of amino acid sequences for 12 protein-coding genes suggested palaeacanthocephalan species to be monophyletic, and this group to be sister to Eoacanthocephala. These results confirm other morphological and molecular data supporting palaeacanthocephalan monophyly.