The Molecular Systematic Study On Cryptocercidae

This research is a thesis of molecular phylogeny of Cryptocercidae which belongs to Blaberoidea, Blattodea, Dictyoptera. There is only one genus Cryptocercus (12species) in the world. They are subsocial insects of biparental family groups which are the smallest group of cockroaches, living in temperate forests of the Nearctic, Oriental and Palaearctic. Because of the transition group between termites and cockroaches, Cryptocercus is increasingly becoming the focus of systematic research in recent years.The fragment sequences of12S rRNA,16S rRNA, COⅡ gene of5Cryptocercus species (17locations) in mitochondrion were sequenced and those of7Cryptocercus species were obtained from GenBank. We used Bayesian (MrBayes3.2), Maximum Likelihood and Parsimony (Paup4.0b10), combining Modeltest3.7, MEGA5.05etc. to construct molecular phylogenetic trees and discuss the phylogenetic relationships of all Qyptocercus species and splitting time between Palearctic and Nearctic, Oriental Cryptocercus according to genetic distance.On the basis of known DNA sequences and type localities of known species, the domestic known species are identified and the wrong identification of Cryptocercus primarius Bey-Bienko,1938by Nalepa et al is corrected. Partial sequences of12S rRNA,16S rRNA, and COⅡ gene of C. primarius and C. hirtus Grandcolas&Belles,2005are provided in this study for the first time. Distribution of C. hirtus and C. primarius is expanded to a great degree. By molecular phylogenetic trees and genetic distance, two specific groups, i.e., Nearctic Cryptocercus species group and Palearctic, Oriental Cryptocercus species group are firstly make certain. It has been found that the interspecific genetic relationships within species group are closer, and those between different species groups are much farther and the minimum genetic distance is above 10%which shows the two species groups will trend to evolve into two Genus. The interspecific genetic relationships among Nearctic Cryptocercus species group are much farther than those of Palearctic and Oriental Cryptocercus species group. In Palearctic and Oriental Cryptocercus, C. kyebangensis and C. meridianus are sister groups, and both of them is the sister group of C. relictus which denys the point of view of Grandcolas (2001b) that C. kyebangensis was the sister group of Nearctic Cryptocercus; and then C. primarius stands as a sister group of all other Palearctic and Oriental Cryptocercus. The new taxa and new synonyms are listed as follows:New species:Cryptocercus arcuatus sp. nov.(Yunnan, Shangri-La), Cryptocercus convexus sp. nov.(Sichuan, Yaan).New synonyms C. parvus Grandcolas&Park,2005, syn. nov.(=C. relictus Bey-Bienko,1935), C. matilei Grandcolas,2000, syn. nov.(=C. primarius Bey-Bienko,1938).And the two new species are sister groups based on molecular phylogenetic trees. Meanwhile the splitting time of Palearctic and Oriental Cryptocercus species group from Nearctic Cryptocercus species group are estimated by Molecular Clock, which can be dated back to the period between late Miocene and Quaternary.The type specimens of the new species are deposited in the College of Plant Protection, Southwest University (SWU).