Phylogenetic reconstruction of Tuberolachnini and Lachninae (Insecta, Hemiptera): Morphological and molecular analyses revealed a new tribe.

Background: Lachninae (Insecta: Aphididae) represent a fascinating group of aphids that are traditionally divided into five tribes. Among these, members of the tribe Tuberolachnini exhibit remarkable morphological and biological diversity. One genus of this group, Miyalachnus, known from Japan, is characterized by unique features. Our study aimed to re-examine the tribal classification within Lachninae, with a focus on the diverse Tuberolachnini and the previously understudied genera Miyalachnus and Sinolachnus.

Results: We conducted a comprehensive phylogenetic analysis using four genes (COI, COII, CytB, and EF1α), employing both maximum likelihood (ML) and Bayesian inference (BI) methods on a combined dataset. Our findings challenge the monophyly of Tuberolachnini. The analyses revealed that Miyalachnus and Sinolachnus are phylogenetically distinct from the core Tuberolachnini genera (Nippolachnus, Pyrolachnus, and Tuberolachnus), instead showing a closer relationship with Tramini. Specifically, the Miyalachnus clade forms a sister clade to the clade containing Sinolachnus and Tramini.

Conclusions: On the basis of these molecular results, corroborated by morphological evidence, we propose to erect a new tribe within the Lachninae-Miyalachnini trib. nov. with Miyalachnus as the type genus. We also provide updated taxonomic diagnoses for the remaining tribes and discuss their relationships as well as distinguishing features.