Molecular and morphological phylogeny of thistle fruit flies Acanthiophilus Becker 1908 and Tephritomyia Hendel 1927 (Diptera: Tephritidae)

Acanthiophilus and Tephritomyia are medium-sized genera in the family Tephritidae. Both exclusively infest plants of the tribe Cardueae and share several morphological characters. Although both were recently revised based on morphological characters, the phylogenetic relationships between these genera and between them and allied genera in the ‘Tephritis group’ remain unclear because no comprehensive morphological or molecular phylogenetic study has been conducted on the group as a whole. Here, we examine whether the two genera form a monophyletic group as suggested by their morphology and life history attributes, and their position within the Tephritis group. We analysed data from two mitochondrial and one nuclear gene as well as 26 morphological characters using Bayesian inference, Maximum Likelihood, and cladistic methods, and conducted an ancestral state analysis to investigate the evolution of morphological traits in this group. Our results confirm the monophyly of Acanthiophilus and Tephritomyia but contrary to our original hypothesis, these genera do not together form a monophyletic group. Instead, they group with Trupanea, which is not restricted to Cardueae host plants. The ancestral state reconstruction suggests that wing pattern and oviscape length are homoplastic characters in the Trupanea clade and are unreliable characters for phylogenetic inference.