Micromacrocera stenobasis L. PAPP, 2008

Papp, L, 2008, Micromacrocera Gen. N., The Smallest Macrocerine Fly (Diptera: Keroplatidae, Macrocerinae), Acta Zoologica Academiae Scientiarum Hungaricae 54 (1), pp. 13-21 : 16-19

Micromacrocera stenobasis L. PAPP , sp. n.

( Figs 1–15 )

Holotype male ( HNNM): RSA: Eastern Cape Prov., Bloukrans Pass , in a side valley – Jan 17, 2007, No. 23, GPS16, S33°57’09.6” E23°37’59.4”, 70 m, leg. L. Papp & M. Földvári. [Its body is in a balsam preparation (see above), wings prepared on a slide, genitalia with the 8th segment in a plastic microvial with glycerol.]

Measurements in mm: body length 1.48, wing length 1.92, wing width 0.75.

Body dark brownish grey, microtomentose.

Head as in Figs 1–2 . Length of left flagellomeres: 23, 16.5, 19, 19, 20, 19, 17, 16, 16.5, 13.5 (others lost) (1 unit = 0.011mm), width of 1st flagellomere 0.043 mm, that of the 10th one 0.022 mm. Basal palpomere minute, third palpomere rather large with 7 setae, fourth palpomere with 4 setae.

Pronotum short. Pleural sclerites bare, including laterotergite, no setae cranial or caudal to anterior spiracle. Scutellum only 0.7 mm long, at most with 4 dorsal macrosetae. No acrostichal setae. Dorsocentrals sparse (6–7). Some setae present on the postpronotal and notopleural areas. Metanotum not small, angular in lateral view, mediotergite left free.

Wing ( Fig. 15 ) comparatively large, longish rather than broad, broadest just behind M 1 -M 2 fork. Wing light brownish, veins brown. Costa continued to 25/33 i.e. ca. 3/4 section between apices of R 5 and M 1. Longitudinal veins (incl. Cu 1) setose dorsally, medial stalk (M 1+2) free of setae. Wing margin sections (base to virtual apex of Sc, Sc-R 1, R 1 -R 5, R 5 -M 1, M 1 -M 2): 45–47–58.5–34–20.5 (1 unit = 0.011mm). R 5 and basal part of M 3 merged/confluent into a thick R-M fusion (0.09 mm long). R4 absent but a small thickening on R 5 represents base of R 4. M 1 and M 2 not completely reaching wing margin. Base of M 3 not pigmented. Veins Cu 1 and M 3 approaching near R-M fusion, similarly to Macrocera . Cu 2 and A 1 can be traced to the level of R-M only. A 1 slightly thicker than Cu 2. A2 not discernible at all. Longest cilia on hind margin 0.033 mm. Halter dark.

Fore leg ratios: coxa 29, trochanter 8, femur 45.5, tibia 53, basitarsus 21.5, tarsomeres 2–5: 11.5, 10, 8, 9 units. Mid coxa 24, trochanter 10, femur 52.5, mid tibia 68, length of tarsomeres on mid leg: 34.5, 16, 12.5, 9.5, 8.5 units. Length of hind coxa 22, trochanter 10, femur 64, tibia 82, basitarsus 45 units (left mid and hind leg and right hind tarsomeres 2–5 lost) (1 unit = 0.011 mm). Basitarsi long and rather thin ( Fig. 7 ). Mid tibial spurs minute: 0.022 and 0.025 mm. Hind tibia with medium-long dorsal setae from 30/82 to 63/82 (more distal ones are short). Length of anteroventral spur on hind tibia 0.028 mm. Hind tibia with only an anteroventral spur; posteroventral spur missing (see above). The black anterior spine (“paired” with the extant spur, see Fig. 8 ) cannot be regarded as a spur.

Abdomen comparatively long with 8 normal pregenital segments. Both tergites and sternites broad, in each segment tergite and sternite almost meet laterally, i.e. intervening membranous area rather small. Spiracle pairs 1–7 are situated in membrane. Tergite 8 ( Fig. 11 ) not much shortened, 0.9 times as long as tergite 7; tergal setae only 0.02–0.022 mm long. Sternite 8 short, not much more than half as long as tergite (0.57×). Tergite 9 comparatively long, anterior edge broadly emarginated, caudally largely pentagonal ( Fig. 12 ). Cerci with 2 pairs of rather short apical setae.

Male genitalia as Figs 12–14 . Left and right gonocoxites fused but on a short section only. Parameres with long lateral arms joining long gonocoxal apodemes. Sclerite connecting parameres with basiphallus very short compared to that of Macrocera spp. Phallus (distiphallus) membranous, disintegrated when treated with sodium hydroxide. The medial, slightly asymmetrical sclerotized structure ventral to the level of tip of parameres and gonocoxal apodemes must be regarded as ejaculatory apodeme. There are 2 pairs of parameral lateral arms: one dorsal, connected to gonocoxal apodemes; the ventral pair as long as dorsal one, completely overlapping it ( Fig. 13 ), slightly ventrally curved pair of processes may support phallus. Gonocoxal apodemes connected by a lamina, which is distinct though not strongly sclerotized, and which connects gonocoxal apodeme apices with basiphallus (not seen in Macrocera ). Inner wall of gonocoxites almost complete, i.e. ends not far from base of gonostylus with a basal lateral process. Consequently, lateral half of the apex of gonocoxites with a U-shaped emargination, which allow moving the apex of gonostylus laterally.

Female unknown.

Etymology. The specific epithet (Latin ‘stenobasis’ [noun] = narrow base) refers to the reduced (narrow) basal part of the wing.

Figures

Figs 1–4. Micromacrocera stenobasis sp. n., holotype male. 1 = head laterally with scape and pedicel, 2 = mouth-parts in a ventral, sublateral view (stipes and cardo dark); 3 = first flagellomere, 4 = 10th flagellomere. Scale: 0.2 mm for all

Figs 5–10. Micromacrocera stenobasis sp. n., holotype male. 5 = thorax with coxae, lateral view, 6 = apex of right fore tibia, anterior view, 7 = contour of fore basitarsus, anterior view, 8 = apex of left hind tibia, anterior view, 9 = fore tarsomere 5, lateral view, 10 =apex of fore tarsus, dorsal view. Scales: 0.4 mm for Fig. 5, 0.2 mm for Fig. 7, 0.1 mm for Figs 6, 8–10

Figs 11–12. Micromacrocera stenobasis sp. n., holotype male, terminalia.11 = tergite and sternite 8, ventral view (tergal setae omitted), 12 = tergite 9 and proctiger, dorsal view (hypoproct covered). Scale: 0.1 mm

Figs 13–14. Micromacrocera stenobasis sp. n., holotype male, genitalia. 13 = dorsal view, 14 = ventral view. Scale: 0.1 mm

Fig. 15. Micromacrocera stenobasis sp. n., holotype male, photo of the wings dorsally