Morphological characters for species-level identification of Synopeas Förster (Hymenoptera: Platygastridae: Platygastrinae)

The genus Synopeas Förster (Hymenoptera: Platygastridae: Platygastrinae) has been largely neglected by modern professional systematics, and the absence of a diagnostic framework constitutes a serious taxonomic impediment. Most species descriptions are incomplete, insufficiently illustrated, and based on one or few specimens. This study identifies external morphological characters important to Synopeas species identification, with a focus on differentiating intraspecific from interspecific variation. Material examined included more than 280 specimens representing 56 species. Microphotographic techniques were used to illustrate characters of interest. Important morphological characters included cuticular sculpture, setal arrangement, and ocular-ocellar length. The shape of the mesoscutellar spine exhibited some intraspecific variation. The results call into question previous species descriptions based solely on mesoscutellar spine morphology, and provide a visual reference guide for future work on Synopeas.