Sphex gaullei, Berland, 1927

Dörfel, Thorleif H. & Ohl, Michael, 2022, The wasp genus Sphex in Sub-Saharan Africa (Hymenoptera: Sphecidae), European Journal of Taxonomy 796 (1), pp. 1-170 : 122

Species of the gaullei group

The gaullei group contains the following five species: Sphex decipiens , S. gaullei , S. jansei , S. pruinosus and S. schmideggeri sp. nov.

Members of this group can be recognized through a combination of anteriorly-oriented, curved erect propodeal setae and a convex scutellum. The orientation of the setae is best visible near the lateral margins of the propodeal enclosure and separates this group from the umtalicus - and meridionalis groups, where the erect propodeal setae are oriented perpendicularly but slightly curved towards anterior as well. Almost all of the species of the gaullei group can still be distinguished through their silvery or golden propodeal setae, whereas most members of the other two groups have them black. Sphex decipiens is a notable exception and can thus easily be mistaken as belonging to the meridionalis group, since, in accordance with the members of that group, it lacks the very dense and coarse setae on the scutellum that are present in the umtalicus group.

The presence of a convex scutellum can be used to delimit members of the gaullei group from those of the satanas group, which share the presence of anteriorly-oriented erect propodeal setae. The difference between the two is very easily recognizable in females ( Fig. 5–6 ), but less pronounced in males. Most of them can be distinguished through the color of the clypeus and the color and density of its vestiture, as all males of the satanas group have the clypeus black (sometimes with the exception of having the free margin ferruginous) and the appressed and erect setae silvery-white without any conspicuous glabrous spots. In contrast, S. jansei , S. gaullei and S. schmideggeri sp. nov. have approximately the lower clypeal half brightly ferruginous, and the first two of them also sport golden erect facial setae. Sphex decipiens has the clypeus uniformly black, but its erect facial setae are also black in contrast to the silvery-white setae of the males in the satanas group. In addition, all males from the gaullei group have a notable glabrous area on the central and lower part of the clypeus, with one exception. The clypeus of male S. pruinosus resembles that of the satanas group members, so the easiest character for distinguishing this species is its elongated petiole, the length of which is around 3.5× its medial width (see Introduction for measurement details). In comparison, this coefficient is between 1.6 and 2.8 for all other males from both groups.

Figures

Figs 1–6. 1–3. Dorsal view of propodeal setae in different orientation. 4. Lateral view of thoracic dorsum. 5–6. Lateral view of scutellum and metanotum. 1. Sphex pseudopraedator sp. nov., ♀. 2. S. jansei Cameron, 1910, ♂. 3–4. S. umtalicus Strand, 1916, ♀. 5. S. rufoclypeatus sp. nov., ♀. 6. S. gaullei Berland, 1927, ♀.