Geometric Morphometric Analysis of Genus Chaetocnema (Coleoptera: Chrysomelidae: Alticini) with Insights on Its Subgenera Classification and Morphological Diversity

In taxonomy, qualitative methods are commonly used to analyze morphological characters, which can lead dramatic changes in higher taxa. Geometric morphometrics (GM) has proven be useful for discriminating species various taxonomy groups. However, the application of geometric supraspecies classification is relatively scarce. this study, we tested controversial two subgenera Chaetocnema with morphometrics; a total 203 representing 50% all known from around world were selected analysis. We analyzed shape pronotum, elytron, head, aedeagus, and spermatheca. The results showed that traditional distinctly differed each other; therefore, propose using arrangements facilitate understanding (especially Oriental, Palearctic, Nearctic regions). Additionally, diversity abovementioned structures was analyzed, it found highest spermatheca, greater than aedeagus. Our research demonstrated GM could detecting delimitation It also applicable insects as small 2 mm body size.