Macrurohelea sirii, Spinelli & Ronderos & Grogan, 2022

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 : 457-458

Macrurohelea sirii n. sp.

( Figs. 26–32 , 47–48 )

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Diagnosis. Females: the only species with flagellomeres 2–8 short, barrel-shaped, 9–12 vasiform, very slightly elongate, 13 longest; thorax dark brown; wing membrane hyaline, veins brown, cell r 3 with faint intercalary vein; halter pale; posteromedian excavation of sternite 8 heavily sclerotized, dark brown; two round, slightly unequal-size spermathecae with short, slender necks. Males: the only species with tergite 10 with lateral margins convergent, apex truncate; apicolateral process minute with medium-size seta; distal portion of parameres slender, slightly divergent distally, apices tapered with outer pointed tip; aedeagus broadly Y-shaped, with a stout, curved medial basal arch and apices short, slender, with adpressed pointed tips.

Female. Head ( Fig. 26 ) dark brown. Eyes separated medially by width of 2 ommatidia with short interommatidial spicules. Antennal flagellum uniformly light brown; flagellomere 1 massive with pair of apical sensilla coeloconica; flagellomeres 2–8 short, barrel-shaped, 9–12 slightly elongate, vasiform, 13 longest, broader than 2–12; antennal ratio 0.74–0.93 (0.84, n = 4). Palpus elongate, light brown; segment 3 with well developed subapical sensory pit; segment 4 short, segment 5 slightly longer than segment 3; palpal ratio 2.00 (n = 4). Mandible with 8–10 coarse teeth. Thorax ( Fig. 27 ) uniformly dark brown; scutum with 3 stout prealar setae, one postalar seta; scutellum with 3 stout setae. Legs uniformly medium brown; palisade setae on tarsomere 1 of hind leg; hind tarsal ratio 2.12–2.33 (2.21, n = 4); tarsomeres 4 cordiform; tarsomeres 5 with pair of small, slightly curved tarsal claws. Wing ( Fig. 28 ) membrane hyaline with numerous microtrichiae; anterior veins dark brown, posterior veins light brown; costa with long setae; second radial cell 1.80–2.63 (2.20, n = 4)x longer than first; cell r 3 with very faint intercalary vein; r-m crossvein as long as petiole of M; medium-size macrotrichiae on costa; wing length 0.94–1.21 (1.09, n = 4) mm, width 0.42–0.54 (0.49, n = 4) mm; costal ratio 0.72–0.75 (0.73, n = 4). Halter pale. Abdomen ( Fig. 29 ) medium brown. Segments 9–10 elongated, bent forward ventrally; sternite 8 stout with broad, rounded posteromedian excavation with heavily sclerotized borders. Two round, slightly unequal-size spermathecae with short, slender necks, diameters 44–56 (49, n = 3) and 40–52 (45, n = 3) µm, necks approximately 10 µm long.

Male. Coloration similar to female with the usual sexual differences. Head ( Fig. 30 ). Eyes broadly separated medially by width of 3 ommatidia. Antennal flagellum with flagellomeres distinctly separated; antennal ratio 0.51–0.59 (0.56, n =6). Palpus slender, elongate, segment 3 slightly longer than segment 5. Tarsal claws small, nearly straight with bifid tips. Wing ( Fig. 31 ) veins brown; 2 nd radial cell 1.22–1.41 (1.32, n = 7)x longer than 1st; a very faint intercalary vein in cell r 3; wing length 0.86–1.06 (1.00, n = 7) mm, width 0.32–0.42 (0.40, n = 7) mm; costal ratio 0.63–0.70 (0.67, n = 7). Abdomen brown. Genitalia ( Figs. 32 , 47–48 ). Tergite 9 extending 0.55 length of gonocoxite, abruptly tapering at mid-length with rounded apex. Tergite 10 with lateral margins slightly convergent, apex truncate, extending 0.70 length of gonocoxite; apicolateral process minute, with medium-size seta; cercus slender, finger-like, slightly divergent. Sternite 9 2.5x broader than long, posteromedian margin slightly convex. Gonocoxite stout, 1.60x longer than sub-basal width, narrowing gradually distally; gonostylus slender, 0.75 length of gonocoxite, curved distally, tip pointed. Parameres ( Fig. 47 ) separate; basal apodeme very stout, recurved 120°, with short, heavily sclerotized, posteriorly directed basal lobe; distal portions slender, closely approximated anteriorly, divergent at mid-length, each half tapering slightly distally with pointed, outer tip. Aedeagus ( Fig. 48 ) broadly Y-shaped, 1.3x broader than long, with stout, slightly concave basal arch, which extends 1/3 of total length; distal extensions short, slender, tapering slightly distally, tips pointed.

Type material. Holotype male, labeled “ Holotype Macrurohelea sirii Spinelli, Ronderos and Grogan ”, “ Argentina, Neuquén, Parque Nacional Nahuel Huapi, arroyo León, 40º43’49’’S, 71º09’11.6’’W, 762 m, 12-XII- 2007 / 3-I-2008, A. Garré – F. Montes de Oca, Malaise trap ” ( MLPA); allotype female, Argentina, Neuquén, Parque Nacional Nahuel Huapi, río Minero, 40°41’23.5’’S, 71°17’33.2’’W, 832 m, A. Garré – F. Montes de Oca , Malaise trap . Paratypes, 6 males, 3 females, as follows: same data as holotype , 4 males, 3 females; same data as allotype , 2 males.

Derivation of specific epithet. We are pleased to name this new species after Dr. Augusto Siri of the Instituto de Limnología “Dr. Raúl A. Ringuelet” La Plata, Argentina, for his friendship and companionship during several collecting trips to Patagonia.

Distribution. Argentina, in Nothofagus forests of Neuquén province.

Discussion. Females of this new species are very similar to those of M. wirthi Spinelli & Grogan , from which they can be distinguished by the distinctly longer distal flagellomeres in M. wirthi and by the intercalary vein of cell r 3 that is fainter in M. wirthi . Males resemble males of M. similis Spinelli & Grogan , but in that species the posterior margin of sternite 9 is straight, the gonocoxite is curved, and the aedeagus is triangular, and its distal portion tapers to a moderately pointed tip. It is also similar to M. morenoi n. sp., but in that species the base of the aedeagus is broader than the bases of parameres and the distal portion is triangular and divided medially with apices slightly divergent, and the distal portion of parameres is stout, nearly straight and slightly divergent distally with rounded tips.

Figures

FIGURES 26–32. Macrurohelea sirii n. sp. Allotype female, 26–29. Holotype male, 30–32. 26, 30 head. 27 thorax. 28, 31 wing. 29 tip of abdomen. 32 genitalia. Scale bars = 0.05 mm.

FIGURES 47–50. Macrurohelea sirii n. sp. Holotype male, 47–48. Macrurohelea ventanensis n. sp. Holotype male, 49–50. 47, 49 parameres. 48, 50 aedeagus.