The mitochondrial genome of a giant dipluran species, Heterojapyx souliei (Diplura: Japygoidea: Heterojapygidae) from the Tibet Plateau

Heterojapygidae is a relict and poorly studied family of Diplura that holds significant importance for understanding dipluran evolutionary history. It has the fewest described species among the 10 dipluran families. This study presents the complete mitochondrial genome of Heterojapyx souliei Bouvier, 1905, the largest dipluran species known to date, from the Tibetan Plateau. This represents the first report of a complete mitochondrial genome from Heterojapygidae. The circular mitochondrial genome is 15,146 bp in length and encodes the 37 typical mitochondrial genes, including 13 protein-coding genes (PCGs), 22 tRNA genes, and 2 rRNA genes, arranged in the same order as in other diplurans. The base composition of the majority strand is 35.26% for A, 28.06% for C, 15.76% for G, and 20.92% for T. Phylogenetic trees inferred from 13 PCGs using the maximum-likelihood (ML) methods show that Heterojapygidae is a sister to Japygidae + Evalljapygidae, suggesting that the divergence of Heterojapygidae occurred later than Parajapygidae, but earlier than Japygidae and Evalljapygidae. Our study fills a critical gap and provides new insights into the phylogeny of Diplura.