Phylogenetic Study Of Corydioidea (Blattodea) Based On Mitochondrial Genomes And Nuclear Genes (18S RRNA And 28S RRNA)

Corydioidea is one of the three superfamlies(the other two are Blaberoidea and Blattoidea)in Blattodea.Up to the end of 2020,69 genera and 366 species(including the fossil taxa)are reported worldwide;while in China,15 extant genera and 54 extant species are recorded.Due to the reclusive habit,it is very difficult in collecting members of Corydioidea,so both of the taxonomic and phylogenetic studies on Corydioidea is far behind other Blattodea groups.First,more baseline survey on the diversity of the superfamily is still necessary,because lots of taxa are still needed to be discovered,identified,described and recorded.Second,the morphological study on this superfamily is still insufficient.Different taxa of this group vary a lot in morphological characters;also,sexual dimorphism is very common in this superfamily,which bring much challenge in the identification of the group.What’s more,the morphological study on the complex male genitalia of Corydioidea is also insufficient.Third,the relationships among the higher taxa are urgently to be clarified,and the evolutionary history of this superfamily is also urgently to be explored.The lag in the Corydioidea study seriously affected the progress of Blattodea phylogeny.Considering the issues above,this thesis comprehensively focuses on the species delimitation based on morphological and molecular data(DNA barcoding),resolving the phylogenetic problems based on mitogenomes plus 18 S r RNA,28 S r RNA genes,and also inferring the divergence time and evolution of this superfamily.Results are listed as follows:The taxonomic and phylogenetic problems,and also the evolutionary history of this superfamily by using both the morphological method and molecular data(mitogenomes plus18 S,28S r RNA genes),the results are listed as follows:The species delimitation of 110 Corydioidea samples was applied using DNA barcoding method(ABGD and GMYC)combined with the morphological evidence.The result shows that 58 morphological species are well supported by the result of ABGD method(60 MOTUs detected),while the GMYC partly supported the morphological result,but with more MOTUs(73 MOTUs)detected.In combination of morphology and molecular data,54 species are successfully identified.cox1 gene also applies well and plays an important role in the male and female pairing,nymph-adult matching,and verification of the polymorphic species.Twenty-eight Corydioidea mitogenomes were obtained,and their comparative studies were also conducted.Results show that Corydioidea’s mitogenomes are highly conserved,the sizes of which only vary from 15,500-16,000 bp,the order of the genes is the same as the model insect,Drosophila yakuba,both of which are circular double-stranded molecule,which contains a typical set of 37 genes,viz.13 protein-coding genes(PCGs),22 transfer RNA genes(t RNAs),two ribosomal RNA genes(r RNAs)and a large non-coding region.No gene arrangements are detected in the studied samples.Corydioidea has an asymmetric nucleotide composition,which shows AT bias.In the PCGs,the average Ka/Ks ratios show that ATP8 has the highest evolutionary rate,while cox1 has the lowest.Phylogenetic analysis was performed using BI and ML methods on the combined data(mitochondrial genome and nuclear genes(18S r RNA,28 S r RNA).The topology shows that Corydioidea is monophyletic,and the sister group of Corydioidea is Blattoidea.Within Corydioidea,two families are confirmed,viz.Corydiidae and Latindiidae.Corydiinae is placed as sister to Euthyrrhaphinae,both constituting the family Corydiidae.While Nocticolidae,Latindiinae(Beybienkonus,Compsodes)and Ctenoneura are grouped together to form one clade,then constituting Latindiidae.Nocticolidae is embedded in Latindiinae,and Latindiinae was found to be paraphyletic.Besides,Eupolyphaga is found to be paraphyletic and should be split into two genera.The divergence-dating analyses of the mitochondrial genome and nuclear data from Corydioidea was speculated in BEAST using 10 fossils for calibration.The crown Corydioidea possibly originated between the Late Jurassic and the Early Triassic(196.90 Ma),the crown Latindiidae originated earlier than the crown Corydiidae.The crown Corydiinae originated in the Early Cretaceous,and its descendants today with the degeneration of the valved subgenital plate in female,while the descendants today of the rest groups(Euthyrrhaphinae and Latindiidae)all with valved subgenital plate in females.Based on the above results,some changes and suggestion in the Corydioidea classification is proposed,Corydioidea consists of 2 family and 5 subfamilies.Ctenoneurinae subfam.nov.is proposed to accommodate Ctenoneura.New discoveries and knowledges on the genera and species of Chinese Corydioidea are provided after the examining of 415 specimens,which including 1 new genus,7 new species,18 new combinations.The checklist of Corydioidea including fossil and extant species and genera worldwide is also provided.New taxa and new combination are listed as follows:New subfamily: Ctenoneurinae subfam.nov.New genus: Pseudoeupolyphaga gen.nov.New species: Eupolyphaga udenostyla sp.nov.;Eupolyphaga miracidia sp.nov.;Pseudoeupolyphaga simila sp.nov.;Pseudoeupolyphaga reducta sp.nov.;Eucorydia minor sp.nov.;Ctenoneura acicula sp.nov.;Ctenoneura abdomina sp.nov.New combination:Pseudoeupolyphaga daweishana(Qiu,Che & Wang,2018),comb.nov.Pseudoeupolyphaga dongi(Qiu,Che & Wang,2018),comb.nov.Pseudoeupolyphaga densiguttata(Feng & Woo,1988),comb.nov.Pseudoeupolyphaga everestiana(Chopard,1922),comb.nov.Pseudoeupolyphaga everestiana reni(Qiu,Che & Wang,2018),comb.nov.Pseudoeupolyphaga fengi(Qiu,Che & Wang,2018),comb.nov.Pseudoeupolyphaga fengi yongshengensis(Qiu,Che & Wang,2018),comb.nov.Pseudoeupolyphaga fusca(Chopard,1929),comb.nov.Pseudoeupolyphaga hengduana(Woo & Feng,1992),comb.nov.Pseudoeupolyphaga maculata(Qiu,Che & Wang,2018),comb.nov.Pseudoeupolyphaga nigrifera(Qiu,Che & Wang,2018),comb.nov.Pseudoeupolyphaga nigrinotum(Qiu,Che & Wang,2018),comb.nov.Pseudoeupolyphaga pilosa(Qiu,Che & Wang,2018),comb.nov.Pseudoeupolyphaga thibetana(Chopard,1922),comb.nov.Pseudoeupolyphaga wooi(Qiu,Che & Wang,2018),comb.nov.Pseudoeupolyphaga xuorum(Qiu,Che & Wang,2018),comb.nov.Pseudoeupolyphaga yunnanensis(Chopard,1922),comb.nov.