The internal sac of aedeagus of longhorned beetles (Coleoptera: Cerambycidae): morphology, nomenclature of structures, taxonomic significance

Abstract

Until recently, the internal sac of the aedeagus (endophallus) of the beetle family Cerambycidae remained practically not investigated. To a large degree such situation is connected with the long term absence of techniques for making dry volumetric preparations for the everted internal sac, which would be adapted to the specific needs of the taxonomic investigation of the family. Such technique has been described only recently and is considered in details in this work. Representatives from 8 subfamilies (more than 100 genera) of Cerambycidae and some species of the families Distenidae and Vesperidae have been investigated. On the basis of the investigated material, the general plan of the structure of endophallus of longhorned beetles is established and the respective nomenclature for its main structures is given. The endophallus is divided into three anatomical parts (phallomeres): basal, medial, and apical. Limits of the phallomeres are established based on structures homologous at the majority of representatives of the family, and thus considered as markers. Prominent membranous structures of the endophallus are designated according to their position concerning the main axis of the latter, namely they are designated as ventral, dorsal, and lateral. The following types of convex membranous structures are distinguished: chambers, tubercles, swellings, blades and appendix. Among sclerites the following structures are distinguished: plates, spines, spicules, riffling and flagellum. In addition to the listed structures, membranous structures and sclerites which are less common, i.e. specific to particular smaller group can be encountered. The system of designations of such structures may be also more specific. Morphology of the phallomeres and the most common structures is described. Their distribution across taxa is considered. Special attention is given to BLV sclerites characteristic to the majority of representatives of the family and always (with rare exception) having the same morphological plan. The most typical morphological features of endophallus are provided for the studied subfamilies

Keywords

• Cerambycidae
• endophallus
• terminology
• structure
• taxonomic significance