Phylogeny and species reassessment of Hyalopterus (Aphididae, Aphidinae)

The broadly distributed genus Hyalopterus currently comprises three formally recognized species that are highly similar morphologically and hence difficult to be identified with certainty. This group has undergone multiple revisions in the past century, but none of these has assessed species from Asia, which has hampered our understanding of the species diversity within this genus. Based on a comprehensive data set from morphological data and host‐associated data, and by coalescent‐based delimitation approaches, the Hyalopterus species boundaries, distribution and diversity were clarified here to further reveal the composition of the species. Two single‐locus (ML‐GMYC and mPTP) and two multilocus (BPP and STACEY) delimitation methods were conducted based on extensive sampling. Then, the phylogenetic relationships and morphological divergence were assessed. Our data strongly supported that the number of recognized species in Hyalopterus had likely been underestimated. The phylogenetic analyses recovered four major clades, which corresponded to distinct host‐plant preferences. Also, the morphological analyses showed significant differentiation for only one of the newly recognized candidate species uncovered by the delimitation approaches, suggesting the existence of at least two independent evolutionary lineages within Hyalopterus arundiniformis , which showed different patterns of host association. Moreover, based on our data, the taxonomic misidentification of H. arundiniformis in China was corrected here. This study lays the groundwork for the thorough taxonomic revision of Hyalopterus and for future evolutionary studies and underlines the importance of an integrated framework for species determination.