One Step beyond Species Description: Unveiling a Fine-Scale Diversity within the Genus Dzhanokmenia Kostjukov (Hymenoptera: Eulophidae)

TL;DR

This study uses DNA barcoding to reveal hidden diversity within the wasp genus Dzhanokmenia and describes a new species.

Contribution

The study introduces a new species and uses DNA barcoding and phylogenetic analysis to clarify the taxonomy of Dzhanokmenia.

Findings

DNA barcoding revealed underestimated species diversity within Dzhanokmenia.

Dzhanokmenia is closely related to Baryscapus based on phylogenetic analysis.

A new species, D. brevifunis, was described and illustrated.

Abstract

Chalcidoidea (chalcid wasps) are one of the most numerically, structurally, and biologically diverse groups in Hymenoptera. However, the conserved morphology coupled with a high intraspecific variability in certain key characters hinders research on chalcids. In this study, DNA barcoding with the COI gene was used to calibrate intra- and interspecific variation in diagnostic characters within the genus Dzhanokmenia. In addition, the nuclear gene, 28S D2, was used to infer a phylogeny to better understand the definition of Dzhanokmenia and its relationships to potentially close genera associated with Tetrastichus. A DNA barcode library that includes eight species was established for Dzhanokmenia. A new species, D. brevifunis Ganbaatar & Cao sp. nov., was described and illustrated. The results show that Dzhanokmenia is closely related to Baryscapus and suggest that the species diversity of Dzhanokmenia is underestimated. This study lays a foundation for further research on the diversity and classification of Dzhanokmenia.

Although Chalcidoidea is one of the megadiverse superfamilies in Hymenoptera, numerous species are still being discovered and described. However, the difficulties in delimiting intra- and interspecific variation hinder this process. In this study, DNA barcoding methods using the COI gene were employed to investigate the morphological variation within Dzhanokmenia Kostjukov, 1977. The nuclear locus, 28S D2, was used to infer a phylogeny to gain an understanding of the relationship of Dzhanokmenia with other potentially close genera. Through a preliminary DNA barcode library established here, including eight species, we calibrated the intraspecific variation in certain diagnostic characters for the new species described here, D. brevifunis Ganbaatar & Cao sp. nov. Maximum likelihood results show that Dzhanokmenia is clustered with the genera associated with Tetrastichus, such as Chaenotetrastichus Graham, 1987, Baryscapus Förster, 1856, Tetrastichus Haliday, 1844, and Oomyzus Rondani, 1870 involved in this study. Our results indicate that the species diversity of Dzhanokmenia is understudied and tentatively confirm that Dzhanokmenia has a potential close relationship with Baryscapus. Along with the DNA barcode library, the referenced phylogeny datasets improve the understanding of the systematic position of Dzhanokmenia within the subfamily Tetrastichinae and the definition of this genus in terms of morphology, thereby facilitating species delimitation, discovery, and description within Dzhanokmenia.

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