Stenobasipteron arnoldi, Bequaert, 1925

Barraclough, David A., 2005, 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, Zootaxa 1094 (1), pp. 41-51 : 46-47

Stenobasipteron arnoldi

( Fig. 1 )

Stenobasipteron arnoldi Bequaert, 1925: 8 .

Holotype ♀: ZIMBABWE: Mt Bambata / Matopos / S. Rhodesia / 23. 3. 1924 / Rhodesia /

Museum; Stenobasipteron / arnoldi / type ♀ J. Beq. / J. Bequaert det; TYPE [rectangular red card]. The holotype (in NMBZ) is in fairly good condition, although the body is extensively greasy.

Discussion: I have examined the female holotype from the Matopos in southwestern Zimbabwe, west of Bulawayo. The habitat was likely to have been dry savanna (Mwabvu, pers. comm.), which is known to be poorly sampled throughout Southern Africa. The female paratype appears to be lost, and is not present in the Museum of Comparative Zoology in Harvard, where Bequaert deposited much of his type material.

Bequaert’s original description is comprehensive and detailed, although his discussion of species affinities is spurious (this so noted in his own hand, in pencil, in the margin of my reprint from the Natal Museum library). Bequaert stated that S. arnoldi was very close to S. gracile , based on material of the latter species available to him (he did not study the type material of S. gracile ). Unfortunately his material of S. gracile belonged to S. difficile , to be placed in Prosoeca (see below). In fact S. arnoldi is distinct from both species. It is readily distinguished from S. gracile (see species key) and is obviously distinct from S. difficile which I have placed in Prosoeca . S. difficile has obvious erect vestiture on abdominal terga 3 and 4, unlike S. arnoldi which has inconspicuous, recumbent vestiture on these tergites, characteristic of other Stenobasipteron species. The two species differ in several other characters, the most important being that of mesonotal and scutellar vestiture. The scutellar disc and much of the posterior two­thirds of the mesonotum are bare in S. arnoldi , but have prominent erect vestiture in S. difficile .

Figures

FIGURES 1–4. Wings of Stenobasipteron and Prosoeca. 1–3. Stenobasipteron. 1. S. arnoldi, female holotype. 2. S. gracile, male syntype. 3. S. wiedemanni, male syntype (bulla at base of first longitudinal vein arrowed). 4. Prosoeca umbrosa, male syntype.