RESUMEN
The genome of the subsocial cockroach Nauphoeta cinerea was partially sequenced in one-twelfth of an Illumina HiSeq lane. The mitochondrial genome was assembled using MIRA software, yielding a circular molecule of 15,923 bp in length and deposited in GenBank under the accession number KY212743. As expected, the mitogenome contained 13 protein-coding genes, 22 transfer tRNAs and 2 ribosomal RNAs. The molecule was assembled using 35,163 sequencing reads of 120 bp each, resulting in â¼286.9× coverage of uniformly distributed reads along the genome. All the 6 complete mitochondrial genomes available for the roaches from the superfamily Blaberoidea were downloaded and compared with the mitogenome of N. cinerea. We also downloaded complete mitochondrial genomes from the superfamily Blattoidea, including 6 mitochondrial genomes of Termitoidae, 2 mitogenomes of Cryptocercoidae and 3 from Blattoidae. A supermatrix dataset presenting the concatenated alignment of all mitochondrial genes was used as input for a maximum likelihood phylogeny. The phylogenomic tree obtained was consistent for most clades, with a relevant exception in the position of the Corydioidea species E. sinensis. Mitochondrial gene information suggests that superfamily Corydioidea should be classified as a clade inside Blattoidea. Nuclear markers and other Corydioidea mitogenomes should be studied to confirm the evolutionary relationships of Blattodea superfamilies.
RESUMEN
Termites (Isoptera) offer an alternative model for the development of eusociality which is not dependent on a high degree of relatedness as found between sisters in hymenopterans (bees, wasps, ants). Recent phylogenetic studies have established that termites belong within the cockroaches as sister to the subsocial Cryptocercidae. Cryptocercidae shares several important traits with termites, thus we need to understand the phylogenetic position of Cryptocercidae+Isoptera to determine how these traits evolved. However, placement of Cryptocercidae+Isoptera is still uncertain. We used both molecular (12S, 16S, COII, 18S, 28S, H3) and morphological characters to reconstruct the phylogeny of Dictyoptera. We included all previously suggested sister groups of Cryptocercidae+Isoptera as well as taxa which might represent additional major cockroach lineages. We used Bayes factors to test different sister groups for Cryptocercidae+Isoptera and assessed character support for the consensus tree based on morphological characters and COII amino acid data. We used the molecular data and fossil calibration to estimate divergence times. We found the most likely sister groups of Cryptocercidae+Isoptera to be Tryonicidae, Anaplecta or Tryonicidae+Anaplecta. Anaplecta has never previously been suggested as sister group or even close to Cryptocercidae+Isoptera, but was formerly placed in Blaberoidea as sister to the remaining taxa. Topological tests firmly supported our new placement of Anaplecta. We discuss the morphological characters (e.g. retractable genitalic hook) that have contributed to the previous placement of Anaplecta in Blaberoidea as well as the factors that might have contributed to a parallel development of genitalic features in Anaplecta and Blaberoidea. Cryptocercidae+Isoptera is placed in a clade with Tryonicidae, Anaplecta and possibly Lamproblattidae. Based on this, we suggest that wood-feeding, and the resultant need to conserve nitrogen, may have been an important factor in the development of termite eusociality. Nocticolidae was placed as sister group to Latindia+Paralatindia (both Corydiidae), this clade was in turn placed as sister group to the remaining Corydiidae. The Nocticolidae+Corydiidae clade is supported by both morphological and COII amino acid changes. Our divergence time estimates placed the split between Mantodea and Blattodea at 273mya (middle Permian) and the splits between the major blattodean lineages no later than 200mya (end of Triassic).