Formal nomenclature and description of cryptic species of the Encyrtus sasakii complex (Hymenoptera: Encyrtidae)

Abstract

With the recent development of molecular approaches to species delimitation, a growing number of cryptic species have been discovered in what had previously been thought to be single morpho-species. Molecular methods, such as DNA barcoding, have greatly enhanced our knowledge of taxonomy, but taxonomy remains incomplete and needs a formal species nomenclature and description to facilitate its use in other scientific fields. A previous study using DNA barcoding, geometric morphometrics and mating tests revealed at least two cryptic species in the Encyrtus sasakii complex. (Hymenoptera: Encyrtidae). To describe these two new species formally ( Encyrtus eulecaniumiae sp. nov. and Encyrtus rhodococcusiae sp. nov.), a detailed morphometric study of Encyrtus spp. was performed in addition to the molecular analysis and evaluation of biological data. Morphometric analyses, a multivariate ratio analysis (MRA) and a geometric morphometric analysis (GMA) revealed a great number of differences between the species, but reliable characteristics were not observed for diagnosing the cryptic species. We thus diagnosed these three Encyrtus species on the basis of the characteristics that resulted from genetic markers (mitochondrial cytochrome c oxidase subunit I and nuclear 28S rRNA) and biological data. A formal nomenclature and description of cryptic species was provided on the basis of an integrated taxonomy.