Morphological Variation Of Dicerapanorpa Magna(chou) And Phylogeny Of Dicerapanorpa(mecoptera: Panorpidae) Based On Geometric Morphometric Analysis Of Wings

Individual morphological variation is a common and an annoying problem in insect systematics. Dicerapanorpa Zhong & Hua, 2013(Mecoptera: Panorpidae) is an endemic genus to China. So far, eight species, D. diceras(MacLachlan, 1894), D. stotzneri(Esben-Petersen, 1934), D. tjederi(Carpenter, 1938), D. kimminsi(Carpenter, 1948), Dicerapanorpa magna(Chou, 1981), D. triclada(Qian & Zhou, 2001), D. baiyunshana Zhong & Hua, 2013 and D. shennongensis Zhong & Hua, 2013 have been record in this genus. Dicerapanorpa magna(Chou, 1981), the type species of the genus, is widely distributed in the Qin-Ba Mountains and varies in morphology between individuals. Individual morphological variation in sexes of D. magna was studied based on comparative morphology and geometric morphometrics analysis. The main results are as follows:Based on observation of D. magna populations from Qin-Ba Mountains, in combination with light and scanning electron microscopy, the male and female genitalia were studied. The results show that the male and female genitalia vary in morphology between individuals and among populations, especially the epandrium, hypovalve, and paramere of male and genital plate and subgenital plate of female.According to the widespread individual morphological variation of D. magna in male and female genitalia, different populations of D. magna collected from Qin-Ba Mountains were examined using landmark-based geometric morphometrics to quantify wing size and shape variations between sexes and among allopatric populations. The results show that sexual dimorphism exists both in wing size and shape in D. magna: female centroid size is larger than male and an expansion or construction of the posterior and distal part of the wing represents shape variation. Because of the wing sexual dimorphism of D. magna, the analyses of wing morphology were conducted separately on the males and females from four localities, respectively. Significant differences exist in female wing size and shape among D. magna populations, not in male. The results suggest that individual morphological variation of D. magna was intraspecific population variation.The phylogenetic relationship was analyzed with UPGMA based on wing morphology, with Cerapanorpa obtusa as the outgroup. The results show that significant differences of wing size and shape were revealed among Cerapanorpa and Dicerapanorpa. The phylogenetic tree confirms the erection of the genus of Cerapanorpa and Dicerapanorpa. It also shows that the species of Dicerapanorpa are clustered together. Furthermore, D. baiyunshanna and D. shennongensis are clustered close to each other, as well as D. stotzneri, D. diceras, D. tjederi and D. triclada, inconsistent with the morphological result of wing. Additionally, the tree suggests a close relationship between D. magna and D. kimminisi because they are located at the top of the tree.In this paper, variation of D. magna populations was analyzed and presented through comparative morphology and geometric morphometrics. The possible reasons are discussed in combination with the divergence time of D. magna and the tectonic and climate events in the Qin-Ba Mountains during the late Miocene-Pleistocene period. Whether reproductive isolation exists between different populations needs further research. Additionally, the phylogenetic relationship was analyzed with UPGMA based on wing morphology for the first time, laying a basis on the study of phylogeny of Panorpidae.