A review of the type material of the Southern African genus Stenobasipteron Lichtwardt, 1910 (Diptera: Nemestrinidae), with transfer of two species to Prosoeca Schiner, 1867

Abstract

Stenobasipteron is a long-proboscid genus of Nemestrininae endemic to southeast Africa (South Africa, Swaziland, Mozambique, Zimbabwe and Malawi), Swaziland and Mozambique being new country records. There has been recent research interest in Stenobasipteron by pollination biologists, and a pollination guild centred on a species reputed to be S. wiedemanni is now established in the literature. Consequently an urgent need has developed to provide accurate identifications of all described species. A provisional generic diagnosis is provided, and problems with distinguishing Stenobasipteron from Prosoeca Schiner are discussed. In addition to the markedly narrowed wing base (a character state traditionally used to identify the genus), the following combination of character states are included in the revised generic diagnosis of Stenobasipteron: striking body markings absent, ocellar protuberance not prominent in profile, proboscis subequal to or longer than body length, wing usually appearing mostly brown infuscate (infuscation sometimes paler towards posterior margin) and abdominal T3 and T4 with short recumbent vestiture (longer erect hairing nearly always absent). The revised generic concept of Stenobasipteron is now found to include only three named species: S. arnoldi Bequaert, 1925 (Zimbabwe), S. gracile Lichtwardt, 1910 (Zimbabwe) and S. wiedemanni Lichtwardt, 1910 (Eastern Cape and KwaZulu-Natal, South Africa). A notable fauna of undescribed Stenobasipteron species occurs in the Mpumulanga and Limpopo Provinces (northeastern South Africa), Mozambique, Zimbabwe and probably Malawi. Two species are transferred to Prosoeca and the following new combinations are established: P. difficile (Bequaert, 1925) (Zimbabwe) and P. minimum (Bezzi, 1924) (Western Cape, South Africa). An annotated key to the accepted species of Stenobasipteron s.s., largely based on type material, is presented