The mitochondrial genome of a stick insect Extatosoma tiaratum (Phasmatodea) and the phylogeny of polyneopteran insects

Abstract

Polyneoptera is an assemblage of 11 insect orders consisting of lower neopteran insects. The interordinal relationships within Polyneoptera remain highly controversial and ancient rapid radiations are thought to be responsible. Phasmatodea, whose phylogenetic position among Polyneoptera is quite unstable, has been thought to be a key taxon to resolve the polyneopteran phylogeny. We determined the full-length sequence of the mitochondrial genome of a stick insect, Extatosoma tiaratum, and explored the phylogeny of polyneopteran insects using nucleic acid as well as amino acid sequences from the mitogenome. Our analyses recovered a close relationship between Phasmatodea, Mantophasmatodea and Grylloblattodea. Dictyoptera was placed as a sister to this group. The monophyly of Orthoptera was confirmed and Plecoptera was placed as a sister group of this order. Six clades are recovered within Phasmatodea in this study and most of them challenge the conventional classification system.