Morphometric Methods in the Taxonomy of Hydrophilidae and Helophoridae (Coleoptera): A Review of Current Approaches in Turkey

Abstract

The families Hydrophilidae and Helophoridae are among the most important groups of water beetles, and the species within these families exhibit considerable morphological variation in both body parts and male reproductive organs. This review examined the suitability of traditional and geometric morphometric methods for identifying species in these families. Accordingly, traditional morphometric analyses supplemented by an examination of the hair arrangement (chaetotaxy) of the species at the larval stage as well as an integrated approach incorporating landmark-based geometric morphometry and molecular data at the adult stage is considered the preferred methodology. Although there are numerous studies in Turkey that examine the systematics, ecological preferences, and extent of exposure to pollutants in the families Hydrophilidae and Helophoridae, studies that combine morphometric analyses with molecular methods are relatively rare. A comprehensive review of the literature shows that chaetotaxy assisted traditional morphometry is the most effective approach during the larval stage, while landmark based geometric morphometry is most effective during the adult stage. This review suggests that studies in Turkey employing these methods in conjunction with molecular data are extremely rare, and integrated taxonomic studies should be a priority for future research.