A revision of the Encarsia mexicana species-group (=Dirphys Howard) (Hymenoptera: Aphelinidae), gregarious endoparasitoids of whiteflies (Hemiptera: Aleyrodidae) in the Neotropical Region †

SIMPLE SUMMARY: Encarsia (Family Aphelinidae) is a genus of minute parasitoid wasps that target a diversity of agricultural pest insects including whiteflies and armoured scale insects. Since the genus was described in 1878, 450+ species of Encarsia have been described. Historically, it has been difficult to provide a subgeneric classification for the species of Encarsia. As a result, researchers have divided the group into numerous informal species-groups. Our work uses an alignment of ribosomal DNA sequences (sequences that code for ribosomal RNA) to construct a phylogenetic tree that shows that species of the genus Dirphys are correctly placed within Encarsia. With these results, we establish the Encarsia mexicana species-group (for the six species previously placed in Dirphys) and describe 14 new species. We also briefly discuss morphological characters that may correspond to the relationships recovered in the molecular phylogeny. With this information, we can better understand the patterns of evolution which brought about the present diversity within Encarsia and provide a more accurate classification of the genus. ABSTRACT: The genus Dirphys Howard 1914 syn. n. is synonymized with Encarsia Förster, and treated as a species-group of Encarsia, referred to henceforth as the Encarsia mexicana species-group. The monophyly of Encarsia is discussed in relation to Dirphys. The new synonymy is based on phylogenetic analyses of the nuclear ribosomal 28S-D2 gene region (43 taxa, 510 bp). The Encarsia mexicana species-group is recovered as strongly monophyletic within Encarsia. All species of the Encarsia mexicana species-group are revised. The group includes six previously described species, and fourteen newly described species. All species are described (or redescribed) and illustrated. Detailed distributional data, and, where available, plant associate and host records are provided for all species. Encarsia myartsevae Kresslein and Polaszek nom. nov. is here proposed as a replacement name for Encarsia mexicana Myartseva, now preoccupied by Encarsia mexicana (Howard). A dichotomous identification key, supplemented by an online multiple-entry key, is provided for all species.