Fig. 1

Extraordinary mt-gene rearrangements were found in booklice compared to different bilaterian clades. A Linearized mt-genome arrangements across six “well-known” genera. They are Mus and Oreochromis representing Chordata, Mytilus from Mollusca, Taenia from Rotifera, Caenorhabditis from Nematoda, Drosophila from Arthropoda. We also show the divergent mt-genome organisation from our focal genus Liposcelis. B Number of gene boundaries (NGBs) of the six representative genera of bilaterians which incorporates together all sequences from the six representative genera. This panel highlights the observation that booklice (Liposcelis) have many more mt-gene rearrangements (i.e. low level of NGBs). C NGBs of four orders in Insecta. This panel compares the level of mt-gene rearrangements across groups of taxa of similar size and age (~ 10 species and ~200 Mya old, see Additional file 2: Table S1). Each of the four clades includes species from only one Insecta order (indicated by different colours)