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Neuropterida is a super order of Holometabola that consists of the orders Megaloptera (dobsonflies, fishflies, and alderflies), Neuroptera (lacewings) and Raphidioptera (snakeflies). Several proposed higher-level relationships within Neuropterida, such as the relationships between the orders or between the families, have been extensively debated. To further understand the evolutionary history of Neuropterida, we conducted phylogenomic analyses of all 13 published transcriptomes of the neuropterid species, as well as of a new transcriptome of the fishfly species Ctenochauliodes similis of Liu and Yang, 2006 (Megaloptera: Corydalidae: Chauliodinae) that we sequenced. Our phylogenomic data matrix contained 1392 ortholog genes from 22 holometabolan species representing six families from Neuroptera, two families from Raphidioptera, and two families from Megaloptera as the ingroup taxa, and nine orders of Holometabola as outgroups. Phylogenetic reconstruction was performed using both concatenation and coalescent-based approaches under a site-homogeneous model as well as under a site-heterogeneous model. Surprisingly, analyses using the site-homogeneous model strongly supported a paraphyletic Neuroptera, with Coniopterygidae assigned as the sister group of all other Neuropterida. In contrast, analyses using the site-heterogeneous model recovered Neuroptera as monophyletic. The monophyly of Neuroptera was also recovered in concatenation and coalescent-based analyses using genes with stronger phylogenetic signals [i.e., higher average bootstrap support (ABS) values and higher relative tree certainty including all conflicting bipartitions (RTCA) values] under the site-homogeneous model. The present study illustrated how both data selection and model selection influence phylogenomic analyses of large-scale data matrices comprehensively.

Tipulomorpha has long been a problematic taxon in terms of familial composition, phylogenetic relationships among families and position relative to other 'lower' Diptera. Whole-transcriptome shotgun sequencing provides a powerful basis for phylogenetic studies. We performed de novo transcriptome sequencing to produce the first transcriptome datasets representing the families Pediciidae, Limoniidae and Cylindrotomidae using high-throughput sequencing technologies. We assembled cDNA libraries for Pedicia vetusta (Alexander) (Pediciidae), Rhipidia sejuga Zhang, Li and Yang (Limoniidae) and Liogma simplicicornis Alexander (Cylindrotomidae). Using the Illumina RNA-Seq method, we obtained 28,252, 44,152 and 44,281 unigenes, from the three respective species. Based on sequence similarity searches, 12,475 (44.16%), 20,334 (46.05%) and 17,478 (39.47%) genes were identified. Analysis of genes highly conserved at the amino acid sequence level revealed there were 1,709 single-copy orthologs genes across the analyzed species. Phylogenetic trees constructed using maximum likelihood (ML) based on the 1,709 single-copy orthologs genes indicated that the relationship between the four major infraorders of lower Diptera was: Culicomorpha + (Tipulomorpha + (Psychodomorpha + (Bibionomorpha + Brachycera))). Trichoceridae belongs within Tipulomorpha as the sister-group of Tipuloidea. Highly supported relationships within the Tipuloidea are Pediciidae + (Limoniidae + (Cylindrotomidae + Tipulidae)). Four-cluster likelihood mapping was used to study potential incongruent signals supporting other topologies, however, results were congruent with the ML tree.

Muscoidea is a significant dipteran clade that includes house flies (Family Muscidae), latrine flies (F. Fannidae), dung flies (F. Scathophagidae) and root maggot flies (F. Anthomyiidae). It is comprised of approximately 7000 described species. The monophyly of the Muscoidea and the precise relationships of muscoids to the closest superfamily the Oestroidea (blow flies, flesh flies etc) are both unresolved. Until now mitochondrial (mt) genomes were available for only two of the four muscoid families precluding a thorough test of phylogenetic relationships using this data source. Here we present the first two mt genomes for the families Fanniidae (Euryomma sp.) (family Fanniidae) and Anthomyiidae (Delia platura (Meigen, 1826)). We also conducted phylogenetic analyses containing of these newly sequenced mt genomes plus 15 other species representative of dipteran diversity to address the internal relationship of Muscoidea and its systematic position. Both maximum-likelihood and Bayesian analyses suggested that Muscoidea was not a monophyletic group with the relationship: (Fanniidae + Muscidae) + ((Anthomyiidae + Scathophagidae) + (Calliphoridae + Sarcophagidae)), supported by the majority of analysed datasets. This also infers that Oestroidea was paraphyletic in the majority of analyses. Divergence time estimation suggested that the earliest split within the Calyptratae, separating (Tachinidae + Oestridae) from the remaining families, occurred in the Early Eocene. The main divergence within the paraphyletic muscoidea grade was between Fanniidae + Muscidae and the lineage ((Anthomyiidae + Scathophagidae) + (Calliphoridae + Sarcophagidae)) which occurred in the Late Eocene.

Sepsid flies (Diptera: Sepsidae) are important model insects for sexual selection research. In order to develop mitochondrial (mt) genome data for this significant group, we sequenced the first complete mt genome of the sepsid fly Nemopoda mamaevi Ozerov, 1997. The circular 15,878 bp mt genome is typical of Diptera, containing all 37 genes usually present in bilaterian animals. We discovered inaccurate annotations of fly mt genomes previously deposited on GenBank and thus re-annotated all published mt genomes of Cyclorrhapha. These re-annotations were based on comparative analysis of homologous genes, and provide a statistical analysis of start and stop codon positions. We further detected two 18 bp of conserved intergenic sequences from tRNAGlu-tRNAPhe and ND1-tRNASer(UCN) across Cyclorrhapha, which are the mtTERM binding site motifs. Additionally, we compared automated annotation software MITOS with hand annotation method. Phylogenetic trees based on the mt genome data from Cyclorrhapha were inferred by Maximum-likelihood and Bayesian methods, strongly supported a close relationship between Sepsidae and the Tephritoidea.

Culicomorpha is a monophyletic group containing most bloodsucking lower dipterans, including many important vectors of pathogens. However, the higher-level phylogenetic relationships within Culicomorpha are largely unresolved, with multiple competing hypotheses based on molecular sequence data. Here we sequenced four nearly complete mitochondrial (mt) genomes representing four culicomorph families, and combined these new data with published mt genomes to reconstruct the phylogenetic relationships of all eight extant culicomorph families. We estimated phylogenies using four datasets and three methods. We also used four-cluster likelihood mapping to study potential incongruent topologies supported by the different datasets and phylogenetic questions generated by the previous studies. The results showed that a clade containing Ceratopogonidae, Thaumaleidae and Simuliidae was the sister group to all other Culicomorpha; in another clade, the Dixidae was basal to the remaining four families; Chaoboridae, Corethrellidae and Culicidae formed a monophyletic group and the Chironomidae was the sister group to this clade; Culicidae and Corethrellidae were sister groups in all trees. Our study provides novel mt genome data in Culicomorpha for three new family representatives, and the resulting mt phylogenomic analysis helps to resolve the phylogeny and taxonomy of Culicomorpha. [ABSTRACT FROM AUTHOR]

The complete mitochondrial genomes ofMusca domestica(Muscidae) andScathophaga stercoraria(Scathophagidae) are circular molecules of 16,108 bp and 16,223 bp in length, respectively. The first complete mitochondrial genome of Scathophagidae is reported here. Both genomes contain all 37 genes, including 13 protein-coding genes (PCGs), 22 tRNA genes, 2 rRNA genes, and a large control region, with conserved arrangement pattern reported in all cyclorrhaphan flies. All PCGs start with standard ATN codons except for theCO1which starts with TCG in both species. All PCGs terminate with the common stop codons TAA or TAG, except for theCO2andND5in both species andND4inS. stercorariawhich end with a single T. [ABSTRACT FROM AUTHOR]