Silba otandjobo, 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 : 10-11

Silba otandjobo sp. nov. ( Figures 25–27 )

Description: Holotype male: Head: Eye with a scatter of fine, short hairs. Frons black, covered with light grey pollinosity, frontal and interfrontal setulae short, not more than 0.1x length of orbital seta, longer along margin with lunule. Orbital plate lightly pollinose, bare apart from orbital seta. Ratio of frons width at narrowest point to eye width 0.5:1. Lunule covered in dense grey pollinosity, as to a lesser extent are the face and parafacial. Antenna entirely black, reaching down to mouth margin, postpedicel length to depth ratio 2.7:1. Arista orange basally, plumose, ratio of plume width at maximum to depth of postpedicel 0.9:1. Anterior genal setulae in a single row of 2–3 along mouth margin, these the strongest setula on the gena.

Thorax: Scutum sub-shining black, with dense black setulae approximately 0.25x length of orbital seta. Anepisternum with a vertical row of 3 anterior and 3 posterior setae, remainder of sclerite with a scattering of setulae which are 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, covering the anterior part of the sclerite. Proepisternum and proepimeron each with a single seta. Scutellum light grey dusted, on margin with five setulae on each side between lateral and apical setae, two between apical setae, all these setulae rather short, approximately 0.1x length of the marginal setae. Calypter white with a dense white fringe. Wing hyaline, veins light yellow, wing length 3.6mm. Legs completely black.

Male terminalia: In lateral view epandrium wider than it is high, bearing strong setae on ventral margin, the most posterior of these the strongest and longest, reaching slightly further than the height of the cercus. Surstylus extending slightly beyond the shell of the epandrium ventrally, extending anteriorly as a rounded lobe, serrate on ventral surface. Cercus approximately 0.3x height of epandrium, bearing long, strong setae along posterior and ventral margins. In ventral view, inner margin of surstylus distinctly emarginated on anterior half where the surface is covered with numerous small spinules, ventral margin with a row of setae, the posterior 4–5 of these long and strong. Inner posterior margin of surstylus with a row of seven peg-like black prensisetae, these becoming increasingly smaller anteriorly. A single strong, medially directed seta present on each side at the base of each cercus. Phallus; basiphallus and distiphallus forming a tube of almost the same diameter, distiphallus 1.8x longer than the basiphallus, slightly fluted and spiculate apically

Female: Unknown.

Diagnosis.

This species belongs to the Silba adipata McAlpine, 1956 species-group which is characterised by having serrated inner margin to the surstylus. Within this group S. otandjobo is distinguished by the epandrium being wider than high with the surstylus slightly protruding ventrally beyond the shell of the epandrium. The phallus is also distinct, although a simple bi-segmented tube. the distiphallus is almost as wide and much longer than the basiphallus, and has a spiculate apex.

Type material. Holotype ♂. TOGO: Région des Plateaux, Otandjobo near Zogbégan (SE of Badou), at river Otandjoboli , 7.5783N 0.6936E, 21.4.200 8, 500m, at river in cocoa plantation, leg. M. von Tschirnhaus. Specimen deposited in SDEI; SDEI-Dip-01003.

Paratype: 1♂, TOGO: Région des Plateaux, Zogbégan, village, at Elèbè creek in a V-shaped valley near cocoa-plantation downstream of village, 7.5805N 0.6675E, 20– 25.4.2008, 650m , remains of secondary rainforest, dense bank vegetation, dead wood, leaf litter, mud and sparsely running water near creek spring, leg. M. von Tschirnhaus. Specimen deposited in NMS; NMS- 10022268 .

Etymology. The specific epithet refers to the town of Otandjobo where the holotype was collected.

Figures

FIGURES 25–27. Silba otanjobo sp. nov. 25. Epandrium and associated structures, lateral view (hypopygium removed). 26. Same, ventral view. 27. Phallus, lateral view.