A revision of the Philoliche aethiopica species complex (Diptera: Tabanidae)

Abstract

The Philoliche aethiopica (Thunberg) species complex has a history of being taxonomically difficult. This group of pollinating flies is of particular interest to botanists and pollination biologists. This paper reviews its taxonomy and redescribes its species with the aid of new morphological and molecular data. Molecular evidence supports the group's monophyly, with two sister-clades, the "aethiopica" clade (= P. aethiopica) and the "rondani" clade (= P. elegans (Bigot), P. rondani (Bertoloni), P. rubiginosa Dias, and P. umbratipennis (Ricardo) stat. rev.). These clades correspond to two species groups defined by male morphology (" aethiopica" group = P. aethiopica and P. formosa (Austen); "rondani" group = P. elegans, P. rondani, P. rubiginosa, and P. umbratipennis stat. rev.). Molecular evidence also reveals a new character, the index of frons divergence, which is diagnostic for the two clades, and is thus a tool for separating previously indistinguishable females of P. aethiopica from P. rondani. Additionally, I show that some of the longest proboscid specimens, previously confused with P. rondani and P. aethiopica, are actually P. umbratipennis (Ricardo) stat. rev. P. rubiginosa, previously known only from Mozambique, is shown to occur in South Africa, and the male of this species is described for the first time. Furthermore, I show that the distribution of morphotypes within species with differing proboscis lengths is geographically structured, with long-proboscid species occurring only in the Albany Centre of Endemism.