Complete mitochondrial genome sequence of Labriocimbex sinicus, a new genus and new species of Cimbicidae (Hymenoptera) from China

Cimbicidae (Hymenoptera, 'Symphyta') in the Paleogene: revision, the new subfamily Cenocimbicinae, and new taxa from the Eocene Okanagan Highlands

We erect the Cenocimbicinae, a new subfamily of Cimbicidae (Hymenoptera, Symphyta), restricted to the Selandian Menat Formation of France, the oldest occurrence of the family, and the Ypresian Okanagan Highlands of far-western North America. We describe new taxa from the Okanagan Highlands: Allenbycimbex morrisae gen. et sp. nov. and Leptostigma n. gen. with seven new species: L. alaemacula n. sp., L. brevilatum n. sp., L. fasciatum n. sp., L. longiclava n. sp., L. longipallidum n. sp., L. longitenebricum n. sp., and L. proxivena n. sp. We revise the Cimbicidae from the Ypresian Green River Formation and the Priabonian Florissant Formation, both in Colorado, USA. The oldest fossil of a modern cimbicid subfamily appears with a single pachylostictine specimen in the Green River Formation, and all Cimbicidae are in modern subfamilies after the Ypresian (we did not examine one larva known from Priabonian Baltic amber). Pseudocimbex clavatus Rohwer 1908 from the Florissant Formation is not a cimbicid; we treat it as Tenthredinoidea incertae sedis. We transfer Cimbex vetusculus Cockerell to Floricimbex n. gen.

The complete mitochondrial genome of the woodwasp Euxiphydria potanini (Hymenoptera, Xiphydrioidea) and phylogenetic implications for symphytans

The long-necked woodwasp superfamily Xiphydrioidea belongs to the suborder Symphyta (Hymenoptera). Here we newly characterize the complete mitochondrial genome of the South Korean Euxiphydria potanini (Xiphydriidae) using next-generation sequencing: 16,500 bp long with 84.27% A + T content and 37 typical mitochondrial genes including those encoding 13 PCGs, 2 rRNAs, 22 tRNAs, and one A + T rich region. We compare the patterns of symphytan mitochondrial gene arrangement with those of an ancestral insect form and found some synapomorphic rearrangements in phylogenetic context. We use a variety of nucleotide and amino acid sequence alignments (thirteen mtPCGs and/or eight nDNAs) alongside step-by-step exclusions of long-branched taxa to elucidate the phylogenetic position of Xiphydrioidea and phylogenetic relationships among the seven symphytan superfamilies, except for Anaxyeloidea of which no mtgenome was available. The monophyly of symphytan superfamilies (with weak support for Pamphilioidea), sister-group relationship of Xiphydrioidea and Cephoidea, and Symphyta being paraphyletic to Apocrita, etc. are consistently supported by maximum likelihood and Bayesian inference trees. We also discuss the problematic phylogenetic positions of Orussoidea and Siricoidea and propose a hypothetical scenario of morphological character transition during hymenopteran evolution based on morphological key characteristics, such as the cenchrus and the wasp-waist.

Phylogenomic Analyses of the Tenthredinoidea Support the Familial Rank of Athaliidae (Insecta, Tenthredinoidea)

The systematic status of the genus Athalia and related genera is a perennial controversy in sawfly taxonomy. Several authors have hypothesized that the placement of Athalia within the Tenthredinidae is artificial, but no studies have focused on this topic. If the hypothesis that Athalia does not belong to Tenthredinidae can be supported, the taxonomic framework of Tenthredinoidea needs revision. We present a comprehensive phylogenomic study of Tenthredinoidae, focusing on the positions of Athalia and related genera by sampling 80 representatives mainly of the Tenthredinoidea, including Heptamelinae and Blasticotomidae. Our phylogenetic reconstructions based on nuclear genes and mitochondrial (mt) sequences support Athalia and related genera as a distinct clade sister to Tenthredinidae + (Cimbicidae + Diprionidae). A comparison of symphytan mitochondrial genomes reveals an innovative gene rearrangement pattern in Athaliidae, in which Dentathalia demonstrates a more ancestral pattern than Athalia and Hypsathalia. The lineage specificity of mt rRNA secondary structures also provides sufficient support to consider Athaliidae as a separate family. In summary, the phylogeny and genomic structural changes unanimously support the taxonomic treatment of Athaliidae as a family and the re-establishment of Dentathalia as a valid genus.

The complete mitochondrial genome of Cimbex luteus (Hymenoptera: Cimbicidae) and phylogenetic analysis

The complete mitochondrial genome of Cimbex luteus was sequenced with 15,127 bp in length. The mitogenome includes 13 protein-coding genes, 22 transfer RNAs, two ribosomal RNAs genes, and an AT-rich region. The nucleotide compositions of C. luteus (43.7% A, 38.0% T, 7.4% G, and 10.9% C) were biased toward A and T. Based on Bayesian inference (BI) and Maximum Likelihood (ML) analyses, C. luteus was identified as one of the basal lineages of family Cimbicidae.

The complete mitochondrial genome of Praia tianmunica (Hymenoptera: Cimbicidae) with related phylogenetic analysis

The complete mitochondrial genome of Praia tianmunica is 15,556 bp long. It contains 37 genes and a control region of 505 bp in length. Gene rearrangement is present in the mitogenome of P. tianmunica. The maximum-likelihood and Bayesian phylogenetic analyses showed that the genus Praia was closely related to genus Labriocimbex.

Nearly complete mitochondrial genome of Trichiosoma vitellina Linné, 1760 (Hymenoptera: Tenthredinidae): sequencing and phylogenetic analysis

The nearly complete mitochondrial genome of Trichiosoma vitellina is 15,245 bp long. It has the A + T content of 81.6% and contains 13 protein-coding genes (PCGs), 22 tRNA genes, and 2 rRNA genes. Gene rearrangement is present in the mitogenome of T. vitellina. All PCGs use standard ATN as start codons, and most PCGs have complete TAN as stop codons. Phylogenetic analysis demonstrates the position of T. vitellina in the Tenthredinoidea. This study provides essential data for the conservation genetics of T. vitellina and advances the understanding of the phylogeny of Cimbicidae.