Silba akloa, 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 : 3-5

Silba akloa sp. nov. ( Figures 3–5 )

Description: Holotype male: Head: Eye bare. Frons, sub-shining black, dulled by greyish pollinosity and microsculpture. Ratio of frons width at point just above lunule to eye width 0.4:1 Orbital plate bare apart from the orbital seta, sub-shining black, dulled by microsculpture. Frontal and interfrontal setulae short, at most 0.2x length of orbital seta, longer setulae present just on margin above lunule. Lunule, ground colour black, covered in greyish pollinosity, parafacial slightly grey pollinose as is the face. Antenna; postpedicel black, long, reaching down below mouth margin, length to depth ratio approximately 2.7:1. Arista yellowish basally, width of plumosity at maximum approximately 0.75x depth of postpedicel. Anterior genal setulae in a single row of 5–6 along mouth margin. Palpus black.

Thorax: Mesonotum sub-shining blue-black, with a covering of short setulae, these approximately 0.3x length of the orbital seta. Anepisternum with a vertical row of three posterior and three anterior setae, with a scattering of setulae anteriorly. One seta on proepimeron and one on proepisternum. Katepisternum with two setae near the dorsal margin, the posterior slightly stronger and positioned slightly more dorsal than the anterior, a scattering of short setulae located along the anterior margin of this sclerite otherwise the surface is bare. Scutellum with a covering of greyish pollinosity, on margin with two setulae between apical and lateral setae on each side, one broken setula evident between apical setae. Calypter whitish with a rather dense white fringe of uniform length. Wing slightly fumose with pale brown veins, wing length 3.6mm. Haltere dark. Legs entirely dark.

Male terminalia: In lateral view surstylus extending posteriorly as a large rounded lobe beyond the shell of the epandrium, posterior prensisetae visible at the base of the cerci. Cercus 0.4x the height of the epandrium, bearing long, strong setae along posterior and ventral margins. Epandrium approximately 1.2x higher than wide with long setae along posterior and ventral margins. In ventral view inner surface of surstylus covered in microsculpture, five large peg-like prensisetae located on posterior margin of surstylus, the posterior two located in a transverse alignment on a setulose posterior projection. Ventral margin of surstylus bearing 4–5 very strong setae posteriorly, these becoming weaker anteriorly. Postgonites large and setulose, bifurcate apically. Phallus relatively simple, distiphallus a long slightly curved tube, partly separated from the deeper basiphallus which has a slightly scaled surface.

Female: Unknown.

Diagnosis. This species with the posterior prensisetae situated on a setulose posterior projection of the surstylus is closely related to Silba figurata MacGowan, 2005 . However, in ventral view the posterior prensisetae of S. figurata are in a posterior—anterior row whilst in S. akola they are transversely arranged. In addition, the inner surface of the surstylus of S. akloa is more extensively covered in micro-sculpture and the phallus, with its deeper basiphallus, is only partly separated from the distiphallus and without spicules.

Type material. Holotype: 1♂. TOGO: Région des Plateaux, Akloa, at Domi creek coming from the Cascades d’Akloa. 7.512N 0.610E, 22.4.200 8. 280m, cocoa / avocado plantation, leg. M. von Tschirnhaus. Specimen deposited in SDEI; SDEI-Dip-01000.

Etymology. The specific epithet refers to the town of Akloa near which the holotype was collected.

Figures

FIGURES 3–5. Silba akola sp. nov. 3. Epandrium and associated features, lateral view. 4. Same, ventral view, Prg = pregonite, Pog = postgonite, Ph = phallus, E = epandrium, Sur = surstylus, Pren = prensisetae, Cer = cerci. 5. Phallus, lateral view.