Integrative Taxonomy of Polynema (Doriclytus) (Hymenoptera: Mymaridae) from Oriental China: Three New Species and Five New Records Revealed by Morphological and Molecular Analyses

Polynema Haliday, 1833 (Hymenoptera: Chalcidoidea: Mymaridae), one of the most species-rich genera in the family, comprises egg parasitoids with diverse hosts across multiple insect orders, some serving as biological control agents for agricultural and forestry pests. The subgenus Polynema (Doriclytus Foerster, 1847), characterized by pronounced morphological conservatism, has historical taxonomic challenges due to reliance on external morphological characteristics. This study employed an integrative taxonomic approach, combining morphological and molecular analyses, to investigate P. (Doriclytus) diversity in the Oriental region of China. Eight species were identified, including three new species—P. (Doriclytus) acutum Wang & Aishan, sp. nov., P. (Doriclytus) daliense Wang & Aishan, sp. nov., and P. (Doriclytus) longicornia Wang & Aishan, sp. nov.—and five species newly recorded from China: P. (Doriclytus) alalatum Rehmat & Anis, 2016, P. (Doriclytus) bicolorigastra Rehmat & Anis, 2016, P. (Doriclytus) dhenkunde Mani & Saraswat, 1973, P. (Doriclytus) dunense Hayat & Anis, 1999, and P. (Doriclytus) tyakshiense Irfan & Anis, 2023. Comprehensive morphological descriptions and diagnostic illustrations are provided for all new taxa, with key diagnostic features detailed for the newly recorded species. Molecular analysis of COI sequences using both the Assemble Species by Automatic Partitioning (ASAP) and Generalized Mixed Yule Coalescent (GMYC) models yielded congruent species delimitation results, with genetic distances between delimited species showing maximum intraspecific divergence of 1.51% and interspecific divergences of 3–12% within the 470 bp COI barcode region. The deposition of 32 novel COI sequences in GenBank significantly enhances molecular resources for Mymaridae systematics.