Macrurohelea monotheca Spinelli & Grogan, 1984

Spinelli, Gustavo R., Ronderos, Maria M. & Grogan, William L., 2022, Five new species in the predaceous midge genus Macrurohelea Ingram & Macfie from Argentina, and descriptions of the previously unknown males of M. kuscheli Wirth and M. monotheca Spinelli & Grogan (Diptera: Ceratopogonidae), Zootaxa 5093 (4), pp. 445-464 : 454-455

Macrurohelea monotheca Spinelli & Grogan

( Figs. 19–21 , 43–44 )

Macrurohelea monotheca Spinelli & Grogan, 1984: 965 (female; Argentina); Spinelli & Grogan 1990: 132 (in key); Spinelli & Wirth 1993: 45 (in list of Ceratopogonidae of Argentina); Borkent & Wirth 1997: 100 (in World catalogue); Spinelli 1998: 325 (in list of Ceratopogonidae of Argentina); Borkent & Spinelli 2000: 49 (in New World catalogue south of the USA); Borkent & Spinelli 2007: 82 (in Neotropical catalogue); Spinelli & Marino 2009: 205 (in list of Ceratopogonidae of Patagonia); Borkent & Dominiak 2020: 164 (in World catalogue).

Diagnosis. Females: the only species with flagellomeres 2–8 short, 9–13 greatly elongated, antennal ratio 1.70; thorax dark brown; wing membrane infuscated, cell r 3 with intercalary fork; second radial cell 3.50x longer than first, halter light brown; one ovoid spermatheca without sclerotized neck. Males: the only species with dark brown thorax; legs with vestiture of short setae; tergite 10 with convex lateral margins; sternite 9 with deep posteromedian excavation; gonostylus moderately curved with two apical points; distal portion of parameres disjunct subapically; aedeagus triangular, with straight lateral margins and stout basal arms with truncate apices, apex slender, with slender heavily sclerotized base and transparent hyaline apical extension.

Male. Head ( Fig. 19 ) dark brown. Eyes separated medially by width of 3 ommatidia, with numerous short interommatidial spicules. Antennal flagellum with flagellomeres distinctly separated, 2–8 globular, 11–13 greatly elongate; antennal ratio 0.59. Palpus dark brown; segment 3 with sensory pit at 2/3 of its length; segment 4 short, segment 5 slightly longer than segment 3; palpal ratio 2.00. Thorax uniformly dark brown; scutum with 5 stout prealar setae, one postalar seta; scutellum with 3 stout, long setae and 5 slender, shorter setae. Legs dark brown; ventral palisade setae on tarsomere 1 of fore, hind legs; tarsomeres 4 cordiform; tarsal claws small, nearly straight with bifid tips. Wing ( Fig. 20 ) membrane slightly infuscated with minute microtrichia, veins brown; second radial cell 2.27x longer than first; cell r 3 with faint intercalary vein; r-m crossvein slightly shorter than petiole of M; mediumsize macrotrichiae on costa; wing length 1.46 mm, width 0.53 mm; costal ratio 0.70. Halter pale brown. Abdomen dark brown. Genitalia ( Figs. 21 , 43–44 ). Tergite 9 extending 0.60 length of gonocoxites, rectangular on proximal 1/3, distal 2/3 tapering to blunt tip. Tergite 10 with convex lateral margins, posterior margin notched; apicolateral processes small, parallel, with short apical seta; cercus short, slender, with apical seta. Sternite 9 1.8x broader than long, with deep, rounded posteromedian excavation. Gonocoxite stout, elongate, 1.85x longer than broad, slightly curved distally; gonostylus 0.69 length of gonocoxite, moderately curved, apex slightly concave with pointed tips. Parameres ( Fig.43 ) broadly separated; basal apodeme broad basally, apex slender, laterally directed at over 90°; distal halves nearly straight, tapered slightly distally, fractured subapically, separated from short, triangular divergent tips. Aedeagus ( Fig. 44 ) slightly triangular, 1.25x longer than basal width; basal arm slender, heavily sclerotized, laterally directed at 45° with blunt tips; basal arch concave, extending 0.22 of total length; lateral margins of distal portion straight, tapering distally to heavily sclerotized, slender subapical, U-shaped process, apex elongate ovoid, lightly sclerotized.

Holotype female, Argentina, Neuquén, San Martín de los Andes , 40°9’39.65”S, 71°21’13.15”W, 23-IV-1982, M. Gentili, light trap ( MLPA, examined).

New record. Argentina, Neuquén, Parque Nacional Lanin, lago Huachulafquen , 39°45’0.70”S, 71°27’21.48”W 28-II-1998, G. Spinelli, aerial net, 1 male ( MLPA) .

Distribution. Argentina, known only from Neuquén.

Discussion. The male described herein exhibits common features with females, such as distal flagellomeres greatly elongated, palpal segment 3 with sensory pit at 2/3 of its length, wing membrane slightly infuscated with minute microtrichia, veins brown, cell r 3 with intercalary vein, r-m crossvein slightly shorter than petiole of M, and halter pale brown.

Males of M. monotheca are similar to males of M. yamana and M. donatoi n. sp. However, M. yamana differs by the shallow, narrow posteromedian excavation of sternite 9, the gonocoxite is as long as the gonostylus, and the parameres are fractured at mid-length. Males of M. donatoi differs from M. monotheca by the apicolateral process of tergite 9 bearing a short inner peg, the posteromedian excavation of sternite 9 is narrow and shallow, and by the aedeagus with convex lateral margins and slender basal arms

Figures

FIGURES 15–21. Macrurohelea kuscheli Wirth, male, 15–18. Macrurohelea monotheca Spinelli & Grogan, male, 19–21. 15, 19 head. 16 thorax. 17, 20 wing. 18-21 genitalia. Scale bars = 0.05 mm.

FIGURES 43–46. Macrurohelea monotheca Spinelli & Grogan, male, 43–44. Macrurohelea morenoi n. sp. Holotype male, 45–46. 43, 45 parameres. 44, 46 aedeagus.