Silba bambesa, Macgowan & Tschirnhaus, 2024

Macgowan, Iain & Tschirnhaus, Michael Von, 2024, Records of Lonchaeidae (Diptera, Cyclorrhapha) from Togo and other African countries, with descriptions of new species, Zootaxa 5514 (1), pp. 1-27 : 5-7

Silba bambesa sp. nov. ( Figures 9–11 )

Description: Holotype male: Head: Eye bare. Frons matt black covered with greyish pollen centrally, with rather short, sparse frontal and interfrontal setulae, these not more than 0.25x length of orbital seta, a few longer setulae present on the anterior margin above the lunule. Orbital plate shining, bare apart from the orbital seta. Lunule with ground colour orange, two setulae present on each side. Parafacial silvered as is the adjoining narrow margin of the face, the remainder of the face lightly silver pollinose. Antenna: postpedicel long and thin, length to depth ratio 2.9:1, reaching down the face to the mouth margin, black apart from an orange area at the extreme medial base. Arista with plumosity at its greatest width equal to the depth of the postpedicel. Anterior genal setae in a single row of four or five, the basal (most posterior) seta the strongest on the genae and much stronger than the other anterior setae, this group separated from the other genal setae by a short distance.

Thorax: Scutum mainly shining blue-black. with light dusting posteriorly in the pre-scutellar area.Anepisternum with a vertical row of two anterior and three posterior setae. Proepisternum and proepimeron each with a single seta. Katepisternum with two strong setae located near dorsal margin, the posterior situated slightly dorsal to the anterior and marginally stronger than it, approximately six scattered setulae on the anterior part of the sclerite. Scutellum, disc with grey-silver dense pollinosity, bare apart from the four marginal setae and one small setula on each side between the lateral and apical setae. Calypter margins and fringes pale yellow, wings slightly fumose anteriorly otherwise hyaline, wing length 3.5mm. Legs, including all tarsomeres, black.

Male terminalia: Epandrium similar to that of S. virescens Macquart, 1851 , that is with the epandrium twice as broad as it is high, cercus relatively large, almost as high as the epandrium and situated at the posterior-dorsal corner of the epandrium. Surstylus, in lateral view, extending from shell of epandrium postero-ventrally as a shark fin shaped process, basal lobe forming a rounded process bearing six to seven strong black teeth. The phallus however is distinctive, in lateral view, with basal section rather boat shaped, with two short equally sized processes projecting ventrally. Apical part linear and angular, attached to basal section by a translucent membrane.

Female: Unknown.

Diagnosis. This species belongs to the Silba virescens species-group which is characterised by features of the male terminalia: an epandrium which is wider than high, a rather triangular posteroventral projection of the surstylus with the prensisetae located on a rounded posterior lobe of the surstylus. The phallus is however clearly distinct and provides the key features used to separate this species from the others in the group.

Type material. Holotype: 1♂. DEMOCRATIC REPUBLIC OF CONGO: Bas Uélé , Bambesa, 3.44N 25.69E, 16.5.193 8, leg. P. Henard. Specimen deposited in RMCA; RMCA ENT 000016323 .

Paratypes: 16 ♂ with the same data as the holotype. Specimens deposited in RMCA .

Additional material: 1♂, CAMEROON: Bamenda Hospital , 5.95N, 10.16W, 4800ft, 7.12.193 7, leg. M. D. W. Jeffrys. Specimen deposited in BMNH .

1♂. TOGO: Région des Plateaux: Otandjobo near Zogbégan (SE of Badou), at river Otandjoboli , 7.5783N 0.693 6W, 21.4.200 8, 500m, at river in cocoa plantation, leg. M. von Tschirnhaus. Specimen deposited in NMS; NMS 10019489 .

Etymology. The specific epithet refers to the locality where the type series was collected.

Figures

FIGURES 9–12. Silba bambesa sp. nov. 9. Epandrium and associated features, lateral view (hypopygium removed). 10. Same, internal view. 11. Phallus, lateral view. Figure 12. Silba virescens Macquart, 1851. Phallus, lateral view.