Silba kakamega, 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 : 7-9

Silba kakamega sp. nov. ( Figures 17–20 )

Description: Holotype male: Head: Eye bare. Frons sub-shining black, dulled by fine microsculpture, frontal and interfrontal setulae short, not more than 0.1x length of orbital seta, longer along margin with lunule. Orbital plate sub-shining blue black, bare apart from orbital seta. Ratio of frons width at narrowest point to eye width 0.5:1. Lunule, ground colour orange brown, when seen from above slightly silver pollinose as are face and parafacial. Antenna entirely black, postpedicel length to depth ratio 2.5:1, reaching down over mouth margin. Arista with long plumes bent forward at apex, ratio of plumosity width at maximum to depth of postpedicel 1.5:1. Anterior genal setulae in a single row of 5–6 along mouth margin, the central setulae of this row long and strong, being the strongest setula on the gena.

Thorax: Scutum sub-shining blue black, with dense black setulae approximately 0.25x length of orbital seta. Anepisternum and katepisternum lightly grey dusted. Anepisternum with a vertical row of two anterior and three posterior setae, remainder of sclerite with a scattering of setulae approximately 0.5x as long as the setae. Katepisternum with two setae located near dorsal margin, the posterior slightly stronger than the anterior, a few setulae lying anterior to the seta and covering the anterior margin of the sclerite. Proepisternum and proepimeron each with a single seta. Scutellum light grey dusted, on margin with three setulae on each side between lateral and apical setae, two between apical setae. Calypter white with a dense white fringe. Wing hyaline, veins yellow-brown, wing length 4.1mm. Legs completely black.

Male terminalia: In lateral view epandrium 2x as high as it is wide, bearing strong setae on posterior and ventral margins. Surstylus extending beyond the shell of the epandrium anteriorly as a rounded lobe, prensisetae visible posteriorly at base of cercus. Cercus approximately 0.3x height of epandrium, bearing long, strong setae along posterior and ventral margins. In ventral view, two isolated prensisetae located on a setulose posterior process of the surstylus, directly anterior to the cercus, in a longitudinal alignment. A further four prensisetae forming a row anteriorly on the posterior part of the ventral margin, two shorter spicules present at the apex of the row. Phallus, a narrow J-shaped tube, bi-segmented, without ornamentation

Diagnosis. This species with the posterior prensisetae situated on a setulose posterior process of the surstylus is a member of the Silba figurata species-group. It is distinguished from other members of the species-group by having the two posterior prensisetae in longitudinal alignment, these isolated from the row of six prensisetae located on inner surface of the surstylus.

Type material. Holotype: 1♂. TOGO: Région des Plateaux: 1 km distance from Adossou, SE of Zogbégan, at Olabè creek . 25.4.200 8, 07°33’29”N 00°41’08”E, 520m, aspirated from fresh human excrement in shade, leg. M. von Tschirnhaus. Specimen deposited in SDEI; SDEI-Dip-01001.

Paratypes: 1♂, TOGO: Région des Plateaux: Cascade de Kpimé W of Huimé. 7.008N 0.6458E, 300m, path to waterfall, road side, 16.4.200 8. Specimen deposited in NMS; NMS- 10021558 . 1♂, Abriwa-Nko, about 5 km N of Badou, at creek Ègnulu-Agbadja , 7.6216N 0.6036E, 310m, plantation (cocoa, avocado), 24.4.200 8, leg. M. von Tschirnhaus. Specimen deposited in NMS; NMS- 10021539 . 5♂, KENYA: Kakamega and Nandi, Kakamega Forest , 8– 9.11.1993, leg. A. Freidberg, Specimen deposited in SMNHTAU .

Additional material: 1♂, CAMEROON: Rt. N 6 Bali Batibo , W of Bamenda, 20.11.198 7, leg. A. Freidberg. 1♂, Rt N9, 20km E of Sangmelima, 7.11.198 7, leg. A. Freidberg. 3♂. Bambalang off Rt. N 11, 35km E of Bameda, 1200m, 18.11.198 7, leg. A. Freidberg & F. Kaplan. All specimens in SMNHTAU.

Etymology. The specific epithet refers to the Kakamega Forest where several paratypes were captured.

Figures

FIGURES 17–20. Silba kakamega sp. nov. 17. Epandrium and associated features, lateral view. 18. Same, ventral view. 19. Inner surface of surstylus. 20. Phallus, lateral view.