The recent expansion of a variety of morphometric tools has brought about a revolution in the comparison of morphology in the context of the size and shape in various fields including entomology. First, an overview of the theoretical issues of geometric morphometrics is presented with a caution about the usage of traditional morphometric measurements. Second, focus is then placed on two broad approaches as tools for geometric morphometrics; that is, the landmark‐based and the outline‐based approaches. A brief outline of the two methodologies is provided with some important cautions. The increasing trend of entomological studies in using the procedures of geometric morphometrics is then summarized. Finally, information is provided on useful toolkits such as computer software as well as codes and packages of the R statistical software that could be used in geometric morphometrics.

Males of Lucanus maculifemoratus Motschulsky are markedly variable in size of body and heads. In this study, we investigated the possible causes that

This paper provides descriptions of two new theridiosomatid species, Theridiosoma nigrivirgatumsp. nov. and Sennin tanikawaigen. nov., sp. nov. from the Ryukyu Islands, southwest Japan, with photographs and illustrations of both sexes. Senningen. nov. is a troglophilic genus composed of two species, S. tanikawaisp. nov. (Iriomote Island, Japan) and S. coddingtoni (Zhu, Zhang & Chen, 2001), comb. nov. (southern China). Zoma dibaiyin Miller, Griswold & Yin, 2009, which recently joined the Japanese fauna, was morphologically reexamined based on specimens from the Ryukyus, and taxonomic features of Zoma males were reassessed. A distributional map of theridiosomatid spiders in the Ryukyus is also provided, including T. dissimulatum Suzuki, Serita & Hiramatsu, 2020, and T. alboannulatum Suzuki, Serita & Hiramatsu, 2020 with their habitat types, web morphology, and web-building behavior in detail.