Simulium (Trichodagmia) (Diptera, Simuliidae) phylogeny revisited: the Neotropical and Afrotropical connection

Óscar S Molina,Leonardo H Gil-Azevedo

doi:10.5852/ejt.2021.773.1517

Óscar S Molina, Leonardo H Gil-Azevedo

Open Access

https://doi.org/10.5852/ejt.2021.773.1517

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Abstract

Simulium (Trichodagmia) Enderlein, 1934 has an unstable classification system. The broader concept of the subgenus includes five species-groups resulting from an extensive history of synonymisations, often outside of a phylogenetic framework. This concept also ignores relationship hypotheses with the Afrotropical subgenera S. (Anasolen) Enderlein, 1930, S. (Freemanellum) Crosskey, 1969, S. (Xenosimulium) Crosskey, 1969, and the Oviedoi species-group, with several Neotropical species of S. (Trichodagmia). We performed a morphological phylogenetic analysis to test the monophyly of S. (Trichodagmia), its species-groups, and their relationship with the above-mentioned subgenera and Oviedoi species-group. We analysed a data matrix with 69 terminal taxa and 62 characters under parsimony implied weights, with a range of concavities (k1–100), finding three categories of k. Our analysis concludes that S. (Trichodagmia) is not monophyletic, since Oviedoi and the Afrotropical subgenera group with its species-groups Tarsatum and Orbitale. Therefore, we propose a new classification for S. (Trichodagmia) by restricting it to the Orbitale species-group, revalidating S. (Hearlea) Vargas et al., 1946, S. (Hemicnetha) Enderlein, 1934, S. (Obuchovia) Rubtsov, 1947 and S. (Shewellomyia) Peterson, 1975, synonymysing S. (Xenosimulium) with S. (Anasolen), and erecting a new subgenus, S. (Disculter) subgen. nov. for Oviedoi. The geographical distribution of the groups involved is discussed.

Highlights

Simuliidae Newman, 1834 (Diptera), commonly known as black flies, has 2331 recognized species distributed in 31 genera, Simulium Latreille, 1802 being the most diverse with 1905 species, 37 subgenera, MOLINA Ó.S. & GIL-AZEVEDO L.H., Phylogeny revisited of Simulium (Trichodagmia) and 110 species-groups (Adler 2020)
The equal weights (EW) analysis resulted in 16 Most-Parsimonious Trees (MPTs), including the three MPTs found with the implied weights (IW) analysis
Our analysis shows that S. (Trichodagmia), S. (Anasolen), S. (Freemanellum), S. (Xenosimulium), and Oviedoi form a monophyletic group based on three synapomorphies (Fig. 1, Table 2, node 1)

Summary

Introduction

Simuliidae Newman, 1834 (Diptera), commonly known as black flies, has 2331 recognized species distributed in 31 genera, Simulium Latreille, 1802 being the most diverse with 1905 species, 37 subgenera, MOLINA Ó.S. & GIL-AZEVEDO L.H., Phylogeny revisited of Simulium (Trichodagmia) and 110 species-groups (Adler 2020). & GIL-AZEVEDO L.H., Phylogeny revisited of Simulium (Trichodagmia) and 110 species-groups (Adler 2020). The relationships among Simulium supra-specific groups are scarcely studied and the diagnoses of several of its subgenera are unsatisfactory (Gil-Azevedo et al 2012). This is especially noticeable in the Neotropical Simulium, for which several authors have proposed different systematic arrangements in the last decades (e.g., Py-Daniel & Moreira-Sampaio 1994; Coscarón & Coscarón-Arias 2007; Shelley et al 2010). The subgenus Simulium (Trichodagmia) Enderlein, 1934 is a good example of this problem. The splitter’s concept of S. (Trichodagmia) [= S. (Trichodagmia) s. str.] (Coscarón & Coscarón-Arias 2007; Coscarón et al 2008) comprises only seven species from the Neotropical Region, and accepts S. (Hearlea) Vargas, Martínez Palacios & Díaz Nájera, 1946, S. (Hemicnetha) Enderlein, 1934, and S. (Thrysopelma) Enderlein, 1934 as valid subgenera

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