Re-evaluating Oriental Metarbelidae (Lepidoptera: Cossoidea): Morphology, Cladistics, and Taxonomic Implications for Psychidarbela and Ratardidae

Metarbelidae are an intriguing group of Cossoid moths that have recently received considerable attention. Although several new genera have been described from the Oriental region in recent years, the morphological diversity of the family remains poorly investigated. In addition, the unusual genus Psychidarbela and the rarely encountered diurnal family Ratardidae share several features overlapping with Metarbelidae. Consequently, Oriental Metarbelidae have remained difficult to delimit, and apomorphic characters are challenging to identify. In this study, we address this gap through an examination of the morphological characters of all Oriental genera. Using a maximum parsimony cladistic analysis based on 39 characters, we find Ratardidae nested within Metarbelidae. Accordingly, we synonymize the two families and recognize Ratardidae, stat. nov., following the ICZN principles of priority. Furthermore, we establish the family-group name Psychidarbelidae Roepke, 1938, stat. nov., for the genus Psychidarbela. Detailed morphological features supporting this arrangement are discussed. This proposal aims to improve diagnostic clarity and stabilize classification; however, it is tentative, and a comprehensive molecular analysis will be required to finalize broader phylogenetic relationships.