| Corydioidea(Insecta,Blattodea)was comprised of 57 genera and 355 species worldwide,of which,16 genera and 58 species are recorded from China.Corydioidea cockroaches could be found in diverse habitats,including soil,decaying wood,caves and insect nests,and species in different habitat usually exhibit distinctions in morphology.The classification of family-group taxa in Corydioidea is mainly based on body size,body pubescence,development of clypeus,wing venation,presence/absence of female wings,and female subgenital plate valvate or not.The delimitation of genus and species relies mainly on the morphology of body and male genitalia,but the delimitation of some species additionally requires female and oothecae characteristics for the accurate identification.With more morphological variations discovered,the species delimitation of some genera(e.g.,Pseudoeupolyphaga and Eucorydia)becomed more challenging.It is urgently needed to explore new characters including morphological and molecular ones.Previous studies found differences in the female genitalia,and suggested their latent taxonomic value.Moreover,the composition and structure of the mitochondrial genome were proven to be species-specific in some insects,which could be used as diagnostic characters;it is worth investigating the taxonomic value in Corydioidea.In addition,the evolution of morphological characters usually reflected the evolution of habitat and habit;however,study about the character evolution in Corydioidea remains lacking.To address these questions and explore the taxonomic significance,the present study investigated the species delimitation in Pseudoeupolyphaga and Eucorydia by combining morphological characters and molecular data using molecular species delimitation methods,and compared the female genitalia,spermathecae and mitochondrial genomes among Corydioidea.This study also reconstructed the phylogenetic relationship based on mitochondrial genome and nuclear genes(18S r RNA and 28 S r RNA),estimated the divergence time with eight fossil calibrations,and performed ancestral state reconstruction based on 14 characters to explore the evolutionary history of Corydioidea.Main findings are as follows:(1)More than 100 specimens of Pseudoeupolyphaga and Eucorydia were observed.Based on external and genital morphology of both sexes,combined with mitochondrial COI gene,25 species of Pseudoeupolyphaga and 9 species of Eucorydia were determined,of which,12 species-group taxa of Pseudoeupolyphaga are new to science:Pseudoeupolyphaga multipunctata sp.nov.,Pseudoeupolyphaga bifurcata sp.nov.,Pseudoeupolyphaga latizona sp.nov.,Pseudoeupolyphaga flava sp.nov.,Pseudoeupolyphaga deficiens sp.nov.,Pseudoeupolyphaga magna sp.nov.,Pseudoeupolyphaga longiseta sp.nov.,Pseudoeupolyphaga baimaensis sp.nov.,Pseudoeupolyphaga yunnanensis tibetensis ssp.nov.,Pseudoeupolyphaga yunnanensis sichuanensis ssp.nov.,Pseudoeupolyphaga fengi cangshana ssp.nov.,Pseudoeupolyphaga dongi tanglishana ssp.nov.In addition,Eupolyphaga regilla sp.nov.,Nocticola furcata sp.nov.and Nocticola bispinata sp.nov.were revealed by male morphological and genital characteristics.(2)R2 sclerite of male genitalia had a strong delimitation power among most species of Polyphagini;female genitalia could be used to distinguish most genera of Corydioidea;the spermatheca was useful for higher taxonmy of Corydioidea,and also served as a basis for species delimitation in Eupolyphaga.(3)Phylogenetic reconstructions consistently supported the division of Corydioidea into Corydiidae and Nocticolidae.In Corydiidae,Corydiinae was sister to Euthyrrhaphinae;but in Nocticolidae,the phylogenetic relationship among Nocticolinae,Latindiinae and Ctenoneurinae was not resolved.The phylogenetic position of Arenivaga and Minpolyphaga kept unstable using different data sets and analytical methods,while the phylogenetic position of the remaining genera was always fixed.(4)The crown group of Corydioidea was estimated to originate during early Triassic,the divergence between Corydiidae and Nocticolidae during middle Triassic,and the divergence between Corydiinae and Euthyrrhaphinae as well as between Nocticolinae and the sister group during the late Triassic to the early Jurassic.(5)Ancestral state reconstruction showed that the common ancestor of corydioid cockroaches was likely to be the species of extant Ctenoneurinae and some species of Latindiinae: lignicolous,body surface indistinctly pubescent,elongated body shape,forewings without Sc-swelling,large terminal spines of front tibia fewer than five;females wingless,subgenital plate valvate,pulvilli and arolia absent or undeveloped;males with undeveloped eyes and ocelli,and obvious pulvilli and arolia.Diverse morphological characters of lignicolous,humicolous and cavernicolous taxa in Corydioidea were strongly correlated to their habitats.The humicolous lifestyle in Corydiinae and cavernicolous lifestyle in Nocticolinae might be the result of dramatic environmental changes around the Triassic-Jurassic boundary,indicating the evolution of morphological specialization associated to the habitat. |
