Species Delimitation Of Anaplectidae And Molecular Phylogeny Of Blattoidea

Anaplecta Burmeister,1838 is a group of small cockroaches distributed worldwide,oviparous,which live under the dead leaves of forest ground and often occurs from April to June.Adults often look for opportunities to mate on the leaves of weeds or shrubs at night..This group was once considered as a transitional group between lower cockroaches and higher cockroaches.In recent years,many studies have shown that Anaplecta should be transferred from Blaberioidea to Blattoidea.At the same time,the relationship between Anaplecta and the other groups in Blattoidea was not clear.Therefore,Anaplecta has become one of the essential key groups to infer the phylogeny of Blattoidea and even Blattodea.In this study,on the one hand,we used classical taxonomic methods to study the morphological classification of Anaplectidae in China,and molecular species delimitation methods to reveal the level of species diversity of Anaplectidae.There are two genera in Anaplectidae:Anaplecta Burmeister,1838 and Maraca Hebard,1926,the latter of which is a monospecies genus and distributed in Brazil,so this study mainly discusses the species delimitation of Anaplecta.At present,there are 94 species in the genus Anaplecta,of which,5 species are from China.Herein we dissected the male genitalia of nearly 500 Anaplecta specimens extensively collected by laboratory staff in recent years and combined two molecular species delimitation methods:ABGD and GMYC to delimit species.On the other hand,based on the mitochondrial genome data,the phylogeny of Blattoidea was analyzed to clarify the taxonomic status of Anaplectidae,and to reveal the phylogenetic relationships among the taxa within Blattoidea.With the addition of the molecular data of Blattodea,it has been shown that Anaplecta should be transferred from Ectobiidae(Blaberioidea)to Blattoidea,which is surprising and unbelievable.Until now,there have been six groups in Blattoidea:Blattidae,Lamproblattidae,Tryonicidae,Cryptocercidae,Anaplectidae and Termitoidae.The phylogenetic relationship among them(except that Cryptocercidae and Termitoidae are sister groups)has always been controversial.In this study,the characteristics of mitochondrial genome of Anaplecta spp.were compared and analyzed by means of comparative mitochondrial genomics,which laid a foundation for the further study.Then 89 mitochondrial genome data(20 groups of laboratory self-sequence data)were combined into two data sets(rRNPCG12tRNA and rRNAPCG12);phylogenetic trees were constructed by using maximum likelihood and Bayesian methods to explore the phylogenetic relationship of Blattoidea,and we inferred the divergence time between the main clades calibrated by 11 fossils.The main results of this study are as follows:1)Ten species of Anaplecta,including eight new species,were identified according to morphological characters,which were also aided by two molecular species identification methods via using the gene maker COI.New species:Anaplecta corneola sp.nov.,Anaplecta staminiformis sp.nov.,Anaplecta arcuata sp.nov.,Anaplecta strigata sp.nov.,Anaplecta furcata sp.nov.,Anaplecta cruciata sp.nov.,Anaplecta nigra sp.nov.,Anaplecta bicolor sp.nov.2)First of all,the phylogenetic relationship of the controversial higher taxon in Blattoidea was clarified,and then the taxonomic status of Anaplectidae was demonstrated again.Blattidae and Tryonicidae,Lamproblattidae and Anaplectidae,and Cryptocercidae and Termitoidae were recovered to be sister groups respectively,which all were supported by 100%support values.The sister group of Termitoidae+Cryptocercidae was recovered to be the sister of clade((Blattidae+Tryonicidae)+(Lamproblattidae+Anaplectidae)),which was the first time to get this result.In addition,according to the results of phylogenetic analysis,a new subfamily,Hebardininae subfam.nov.,was established;both Archiblattinae and Blattinae were not monophyletic group;the former branch name of(Lamproblattidae+(Termitoidae+Crytocercidae)),Kittrickea,proposed by Evangelista et al.(2019)was not accepted.3)Divergence time:The results showed that the divergence time between Blattoidea and Blaberioidea+Corydioidea was 202.02Ma(95%CI 175.02-229.87Ma).In addition,the six groups of Blattoidea formed three branches:Termitoidae+Cryptocercidae,Blattidae+Tryonicidae and Lamproblattidae+Anaplectidae.The earliest division of these three branches was that of Termitoidae+Cryptocercidae,with the divergence time of 192.47Ma(95%CI 167.32-219.5Ma);and the divergence time of the other two branches was 186.78Ma(95%CI 162.3-213.88Ma).