Mitogenomics and the phylogeny of the American subgenera of Simulium Latreille, 1802 black flies (Diptera: Simuliidae)

Abstract

Simulium Latreille, 1802, includes 1,979 valid species distributed across 42 subgenera (Adler, 2024), using 21 of the 42 subgenera and 11 of the 14 described Neotropical subgenera, a phylogenetic analysis based on mitogenomic data was conducted to investigate the American subgenera of Simulium. Two model-based methods – maximum likelihood (ML) and Bayesian inference (BI) - were applied to two distinct datasets: (1) the NT matrix, which included concatenated nucleotide sequences from 13 protein-coding genes (PCGs) and two ribosomal RNA genes (rRNA), and (2) the AA matrix, composed of concatenated amino acid sequences from the 13 PCGs. In addition, a morphological dataset consisting of 21 characters was analysed using ML, with the analyses conducted on the phylogenetic trees derived from AA datasets. We obtained complete mitogenomes for 39 species, with variation in the size of two genomes, which varied from 15,207 to 17,267 base pairs (bp). According to our results, the monophyly of the genus Simulium is supported and we propose elevating Hellichiella n. rank to genus level. The genus Simulium was found divided into two major divisions including six highly supported clades. The first major division comprised S. (Montisimulium) jisigouense, S. (Nevermannia) gouldingi, S.(Simulium) quinquestriatum, Clade I (subgenera Wilhemia and Edwardsellum) and Clade II (subgenera Eusimulium and Nevermannia). The second major division included S. (Psilozia) vittatum, S. (Psilopelmia) escomeli, Clade III (subgenera “Simulium” and Boopthora), Clade IV (subgenera Aspathia, Hemicnetha, Hearlea, Shewellomyia, and Trichodagmia), Clade V (subgenera Chirostilbia, Inaequalium, Psilopelmia, and Psaroniocompsa), and Clade VI (subgenera Psilopelmia, Eremulium, and Pternaspatha). Neotropical Simulium are all Xi recovered in a clade comprising S. (Psilozia) vittatum + S. (Psilopelmia) escomeli + clades IV + V + VI.