Austrohelea spinosa, Ronderos & Spinelli & Grogan, 2017

Ronderos, Maria M., Spinelli, Gustavo R. & Grogan, Willliam L., 2017, The Neotropical species of the predaceous midge genus Austrohelea Wirth & Grogan (Diptera: Ceratopogonidae), Zootaxa 4276 (2), pp. 255-269 : 263-268

Austrohelea spinosa New Species

( Figs. 20 ̄28, 33̄34)

Diagnosis. A large (male wing length 1.50̄ 1.60 mm, female wing length 1.57̄ 1.68 mm), dark brown species. Males with hind tibia with 3 long, stout, black subapical spines; tergite 9 with narrow shallow posterior excavation; gonocoxite short, stout, tapering slightly distally with basomesal tubercle; gonostylus longer than gonocoxite; parameres with very broad basal apodemes that form an obtuse angle between the anterior and posterior arms; and the aedeagus is very large, heavily sclerotized with long basal arms, a U-shaped basal arch and lightly sclerotized apical extension. Females with palpal segment 3 lacking sensory pit, hind femur greatly swollen, and subequal, ovoid spermathecae with moderately long broad necks.

Male. Head ( Fig. 20 ) dark brown. Eyes barely contiguous with fine interommatidial spicules. Antennal pedicel very dark brown; flagellomeres 2̄8 globular, 9̄10 slightly elongate, cylindrical, 11̄13 elongate, 11 longest; plume sparse, well developed, extending beyond apex of flagellomere 11; flagellomere 12 with single subapical sensillum coeloconicum; antennal ratio 0.72̄0.77 (0.75, n = 3). Clypeus with 2̄3 pairs of setae. Palpus slender, extending beyond apex of proboscis; segment 3 without apical pit; palpal ratio 3.64̄4.02 (3.78, n = 3). Thorax. Dark brown; scutellum slightly paler with 9̄11 large, 18̄25 smaller setae. Legs ( Fig. 21 ) dark brown, fore femur slightly paler; fore, mid femora stout, hind femur greatly swollen; hind tibia broader than fore, mid tibiae, hind tibia ( Fig. 22 ) with 3 long, black subapical spines and moderately numerous coarse setae on ventral surface (only insertions remain on most specimens); hind tibial comb with 5 long spines; hind tarsomere 1 with large basal, apical spines; hind tibial ratio 7.90̄8.57 (8.16, n = 3); hind tarsal ratio 1.82̄2.00 (1.89, n = 3); tarsomeres 4 cylindrical; claws short, equal size, without basal inner teeth, apices bifid. Wing ( Fig. 23 ) membrane mostly pale, lightly infuscated on costa, radius and base of medius and on membrane between these veins; veins M1, M2, CuA1, CuA2 and A infuscated; base of M2 obsolete; macrotrichia present on costa, radius and a few along anterior margin of cell r3; wing length 1.50̄1.60 (1.65, n = 3) mm, width 0.50̄0.54 (0.53, n = 3) mm; costal ratio 0.58̄0.62 (0.60, n = 3). Halter pale. Abdomen. Brown. Genitalia ( Figs. 24 , 33 ̄34). Tergite 9 tapering gradually distally, posterior margin straight, apicolateral processes cylindrical, moderately long with a single apical seta, cercus hyaline, slender with 3-4 setae; sternite 9 2.2 x broader than long with narrow shallow, rounded posteromedian excavation. Gonocoxite short, stout, tapering slightly distally, with a small basomesal tubercle; gonostylus 1.3 x longer than gonocoxite, nearly straight, apex broad, spoon-shaped, tip pointed. Parameres ( Fig. 33 ) separate, boomerangshaped; basal apodeme very broad, forming an obtuse angle between anterior and posterior arms; distal portion broadest proximally, curved, tapered distally to mid length, apices recurved, with widely divergent pointed tips. Aedeagus ( Fig. 34 ) triangular, heavily sclerotized; basal arch U-shaped, extending 1/3 of total aedeagus length; basal arm broad, recurved 90˚ near base, distal portion long, tapered apically, apex rounded; distal portion tapering abruptly distally to a narrow sharply pointed tip, with a lightly sclerotized underlying apical process with a bulbous apex and rounded tip.

Female. Head ( Fig. 25 ) dark brown. Eyes barely contiguous ventrally, with fine interommatidial spicules. Antennal pedicel very dark brown; flagellum dark brown, flagellomeres 2̄8 ( Fig. 26 ) moderately short, barrelshaped, 9̄13 elongate, cylindrical; flagellomeres 8, 12 with single subapical sensillum coeloconicum; antennal ratio 1.36̄1.47 (1.39, n = 5). Clypeus with 2̄4 pairs of setae. Palpus ( Fig. 26 ) dark brown; segment 3 moderately slender with a few capitate sensilla on distal 1/3 of mesal surface; palpal ratio 3.00 (n = 5). Mandible with 8̄11 (9, n = 5) large teeth. Thorax. Scutum dark brown, humeral areas and scutellum paler; scutellum with 6̄7 large, 10̄12 smaller setae. Legs dark brown, hind tibia and femur darkest; fore, mid femora moderately swollen, hind femur greatly swollen; hind tibia without subapical spines, stouter than fore, mid tibiae; hind tibial comb with 5 large spines; hind tibial ratio 5.93̄7.17 (6.42, n = 5); tarsi dark brown, darkest on hind leg; tarsomeres 1 with large basal, apical ventral spines, 2 additional similar spines along ventral surface of mid leg, tarsomeres 2̄3 of fore, mid legs with apical spine; tarsomeres 1̄2 of hind leg with two rows of ventral palisade setae; hind tarsal ratio 1.76̄1.88 (1.83, n = 5); tarsomere 4 of fore, mid legs short, cordiform, tarsomere 4 of hind leg elongate, cylindrical; claws small, equal on fore, mid legs, hind leg with single long claw that is slightly longer than tarsomere 5 with a stout basal tooth about 1/3 as long as claw. Wing ( Fig. 27 ) membrane infuscated, particularly dark along veins and in and around radial cells; two well developed radial cells, 2nd broader, twice as long as1st; macrotrichia fairly numerous on distal ½ of cell r3, apices of m1, m2, a few in cua1 and anal cell; wing length 1.57̄1.68 (1.63, n = 5) mm, width 0.65̄0.68 (0.67, n = 5) mm; costal ratio 0.64̄0.66 (0.65, n = 5). Halter pale. Abdomen ( Fig. 28 ) dark brown. Sternite 8 with moderately deep V-shaped posteromedian excavation; sternite 9 separated, each half tapered distally with hook-like apices; sternite 10 with two pairs of setae. Two ovoid, subequal size spermathecae with moderately long, broad necks, measuring 55̄62 (59, n = 5) µm by 35̄42 (39, n = 5) µm; a small rudimentary third spermatheca present.

Type material. Holotype male, ARGENTINA, Neuquen, Villa La Angostura, 11/ 15-I-2004, G. Spinelli, at light ( MLPA) ; allotype female, Argentina, Río Negro, Parque Nacional Nahuel Huapi, mallín La Cortadera , 41°05'13"S, 71°48'26"W, 769m, 14-XII-2006 / 8-I-2007, A. Garré ̄ F. Montes de Oca, Malaise trap ( MLPA) . Paratypes, 2 males, 4 females, as follows: 1 male with same data as holotype ( MLPA) ; 1 male, 4 females with same data as allotype (1 male, 1 female in MLPA, 1 female in BMNH, 1 female in USNM, 1 female in FSCA) .

Distribution. Known only from Nothofagus forests of Nahuel Huapi National Park in Neuquen and Río Negro provinces, Argentina ( Fig. 35 ).

Derivation of the specific epithet. The specific name of this new species is Latin, in reference to the long, coarse, subapical spine-like setae of the male hind tibia.

Discussion. Males of A. spinosa are most similar to those of A. shannoni as they have similar genitalia, however; this new species differs from this previously described congener by the very long stout, black, subapical spines on the hind tibia of males; the posterior margin of tergite 9 is straight and the apicolateral processes are slender and much longer; the gonostylus is longer than the gonocoxite; the parameres are very broad and their basal apodemes form a shallow obtuse angle between the anterior and posterior arms; and the basal arch of the aedeagus is broader and U-shaped.

Females of this new species can be distinguished from those of A. shannoni by their greatly swollen hind femora and subequal size spermathecae with shorter necks.

Figures

FIGURE 35. Map of Argentine and Chilean Patagonia with distribution records of: Austrohelea shannoni (Wirth & Blanton), green circles. Austrohelea sirii n. sp., yellow triangles. Austrohelea spinosa n. sp., red diamonds.

FIGURES 20 – 24. Austrohelea spinosa n. sp. Male. 20. head. 21. legs. 22. hind tibial comb and tarsomere 1. 23. wing. 24. genitalia.

FIGURES 29 – 34. Austrohelea shannoni (Wirth & Blanton). Male. 29. parameres. 30. aedeagus. Austrohelea sirii n. sp. Male. 31. parameres. 32. aedeagus. Austrohelea spinosa n. sp. Male. 33. parameres. 34. aedeagus.

FIGURES 25 – 28. Austrohelea spinosa n. sp. Female. 25. head. 26. palpi and mouthparts. 27. wing. 28. abdominal segments 7 – 10 and spermathecae.