Silba

Macgowan, Iain, 2015, A review of the Silba admirabilis McAlpine species group (Diptera: Lonchaeidae) with descriptions of thirteen new species from the Afrotropical region, Zootaxa 4032 (5), pp. 515-534 : 533-534

Key to males of Silba admirabilis species group

(all Afrotropical unless indicated)

1. Phallus boat-shaped, basal plate fused laterally to phallus, basiphallus spiculate ( Figs. 33–34 )....................................................................................................... chalkei McAlpine ; S.E. Asia.

- Phallus with a distinct ventrally situated basal plate.......................................................... 2

2. Phallus with an additional pair of processes between it and the basal plate ( Figs. 29–30)................................................................................................. admirabilis McAlpine ; India & Sri Lanka.

- Phallus without such additional processes.................................................................. 3

3. Basiphallus with an obvious bulge on inner surface, in anterior view basal plate of phallus simple and lanceolate. (Figs. 35–36)......................................................................... flavitarsis MacGowan ; S.E. Asia.

- Basiphallus without such a bulge or lanceolate basal plate..................................................... 4

4. In ventral view basal plate of phallus diamond shaped ( Figs. 16 & 18)............................................ 5

- In ventral view basal plate of phallus not diamond shaped...................................................... 6

5. Basal plate serrated apically and laterally, apical excavation a narrow V-shape ( Figs. 15–16 )................................................................................................................ lubumbashi sp. nov.

- Basal plate without marginal serrations, apical excavation broader, U-shaped (Figs. 17–18)................ mbuti sp. nov.

6. In ventral view basal plate of phallus with apical margin only slightly concave, without a large V or U-shaped excavation (Figs. 8, 26, 38 &42).................................................................................. 7

- Basal plate of phallus at apex with an obvious V or U-shaped excavation........................................ 10

7. Basal plate long and very narrow, without any marginal serrations or spicules. (Fig. 8)................... bredoi sp. nov.

- Basal plate wider, often with marginal serrations or spicules. ( Figs. 26 , 38 &42).................................. 8

8. Basal plate shorter than phallus, thin and translucent, with serrated margins, basiphallus broad and setulose (Figs. 37 & 38)................................................................................. hilli (Malloch) ; Australasia

- Basal plate as long or longer than phallus. ( Figs. 26 –42)...................................................... 9

9. Apical margin of basal plate strongly serrated ( Fig. 26 ).......................................... upemba sp. nov.

- Apical margin of basal plate almost smooth, with only a few spicules (Fig. 42).................... namibia MacGowan

10. In ventral view basal plate of phallus markedly swollen medially, apex with two diverging processes with between them an open U-shaped excavation (Fig 24)............................................................. tekei sp. nov.

- In ventral view basal plate of phallus not markedly swollen medially........................................... 11

11. Basal plate of phallus bearing spicules across its ventral surface ( Figs 22 & 32 )................................... 12

- Basal plate of phallus without spicules across its ventral surface................................................ 13

12. Basal plate covered in large spicules, apically with a large open V-shaped excavation ( Figs. 31–32 ).... apodesma McAlpine

- Basal plate bearing only small spicules, mostly along margins, apically with a U-shaped excavation ( Figs 21–22)................................................................................................ spiculata sp. nov.

13. In ventral view basal plate of phallus narrow, with a spanner-shaped apex ( Figs. 9–10)................. garamba sp. nov.

- In ventral view basal plate of phallus usually broader, without such a spanner-shaped apex.......................... 14

14. In ventral view basal plate of phallus apically split for almost half of its length ( Figs. 20 & 28)...................... 15

- In ventral view basal plate of phallus without such a deep split............................................... 16

15. Basal plate of phallus with two thin leaf-like parallel, gradually tapering, bluntly pointed apical lobes ( Figs. 27–28)................................................................................................. wittei sp. nov.

- Basal plate of phallus with parallel apical lobes constricted near apex, in lateral view with expanded apex. ( Figs. 19–20)............................................................................................ saegeri sp. nov.

16. In ventral view basal plate of phallus with two square-ended apical processes separated by a V-shaped excavation. ( Figs. 39– 40 ).................................................................. israel MacGowan and Freidberg ; Israel .

- Basal plate of phallus without square ended apical processes.................................................. 17

17. In lateral view basiphallus very broad and rounded ( Fig. 11 ). In ventral view basal plate widening at apex, forming two rather narrow, lateral apical processes separated by a wide apical excavation ( Fig. 12 )....................... hambai sp. nov.

- In lateral view basiphallus not greatly broadened ( Figs. 3 , 5, 13 & 43).......................................... 18

18. In ventral view basal plate widening steadily from base to apex, apical processes almost parallel sided, apical excavation a rel- atively wide U-shape ( Figs. 3–4 )............................................................ bakongo sp. nov.

- In ventral view basal plate broadest before the apex or straight sided (Figs. 6, 14 & 44)............................ 19

19. In ventral view basal plate parallel sided, apex with two pointed processes divided by a U-shaped excavation (Figs. 43–44)................................................................................... pappi Soós ; Afghanistan

- In ventral view basal plate not parallel sided, broadest before the apex (Figs. 6 & 14).............................. 20

20. Basal plate broadened apically, in ventral view widest at apical third, apical processes slightly bulbous at apex, apical excavation a narrow mouthed U-shape, basiphallus not swollen. (Figs. 5–6)................................ boulangi sp. nov.

- Basal plate thin and translucent, in ventral view at apical quarter before narrowing to apex with a V-shaped apical excavation, in ventral view basiphallus slightly swollen (Figs. 13–14)......................................... inimvua sp. nov.

Figures

FIGURES 33 – 34. Silba chalkei McAlpine. 33. Phallus lateral view. 34. Same, ventral view. FIGURES 35 – 36. Silba flavitarsis MacGowan. 35. Phallus lateral view. 36. Same anterior view. FIGURES 37 – 38. Silba hilli (Malloch). 37. Phallus lateral view. 38. Same ventral view.

FIGURES 15 – 16. Silba labumbashi sp. nov. 15. Phallus lateral view. 16. Same ventral view. FIGURES 17 – 18. Silba mbuti sp. nov. 17. Phallus lateral view. 18. Same ventral view.

FIGURES 25 – 26. Silba upemba sp. nov. 25. Phallus lateral view. 26. Same ventral view.

FIGURES 31 – 32. Silba apodesma McAlpine. 31. Phallus lateral view. 32. Same ventral view (after McAlpine, 1956)

FIGURES 39 – 40. Silba israel MacGowan & Freidberg. 39. Phallus lateral view. 40. Same ventral view. FIGURES 41 – 42. Silba namibia MacGowan. 41. Phallus lateral view. 42. Same ventral view. FIGURES 43 – 44. S ilba pappi Soos. 43. Phallus lateral view. 44. Same anterior view.

FIGURES 11 – 12. Silba hambai sp. nov. 11. Phallus lateral view (apex broken off). 12. Same, ventral view. FIGURES 13 – 14. Silba inimvua sp. nov. 13. Phallus lateral view. 14. Same, ventral view.

FIGURES 3 – 4. Silba bakongo sp. nov. 3. Phallus lateral view. 4. Same, ventral view. FIGURES 5 – 6. Silba boulangi sp. nov. 5. Phallus lateral view. 6. Same, ventral view. FIGURES 7 – 8. Silba bredoi sp. nov. 7. Phallus lateral view. 8. Same, anterior view.