Argentinomyia opaca ( Fluke, 1945 )

Montoya, Augusto L. & Wolff, Marta, 2023, Taxonomic revision of the Neotropical genus Argentinomyia Lynch-Arribálzaga, 1891 (Diptera: Syrphidae), with description of 16 new species, Zootaxa 5234 (1), pp. 1-157 : 102-103

Argentinomyia opaca ( Fluke, 1945)

Proposed standard English name: Opaque long-antennae flower fly.

( Figs 59, 60 and 90D)

Rhysops opaca Fluke, 1945: 10 . Type locality: Ecuador. Chimborazo, Urbina, Cerro Chimborazo, 3650m. HOLOTYPE Male AMNH (Examined). Refs.: Fluke,1945: 26 ( Fig. 15, Head, lateral view, Male); 1957: 279 (Figs 115–116, male genitalia)

Rhysops opaca . Fluke, 1957: 266

Rhysops opacus . Thompson, 1976: 44

Argentinomyia opaca . Montoya, 2016: 461

Argentinomyia opaca . Marín-Armijos et al. 2017: 168

Type material. HOLOTYPE. Adult Male, ECUADOR. Urbina, Cerro Chimborazo, 3650 m, 18.iv.1939, F.M. and H. Brown ( AMNH) . ALLOTYPE. ECUADOR. Label with the same data as Holotype (1♀, AMNH) . PARATYPE. ECUADOR. Label with the same data as Holotype (6♁, 15♀ AMNH; 1♁, 2♀ USNM ENT 00058845 ; 3♁, 2♀, WIRC) .

Length (n= 4): Body, 5.2–6.5 mm; Wings, 5.3–5.7 mm.

Diagnosis. A small, entirely black species. Face perpendicular with a well-rounded tubercle, deeply concave dorsally, with no distinct transversal grooves; antennae are entirely black; scutum brownish-yellow pilose; halter white; legs dark, only bases of the tibia and metafemur reddish; abdomen black with grey metallic maculae, never continuously pale basally. Hypandrium narrowed laterally towards the apex; apex of hypandrium (superior lobes) feline claw shape.

Redescription. MALE. Head ( Fig. 59A): Face shining black. Frontal triangle wide and gena lightly dusted with white pollen; the pile of the face and gena white and of frontal triangle black. Face nearly perpendicular with a large, well-rounded tubercle, deeply concave above the tubercle. Ocellar triangle shining black, with black pile in front and brownish pile near occiput; cilia Black, occipital yellow pilose ventrally. Antennae black, short, ratio 1.6:1.0:1.4, scape longer than pedicel, shorter than basoflagellomere, which is shorter than the scape and pedicel; arista black, pilose. Thorax ( Figs 59B–C): Black; mesonotum shining; with a pair of faint brownish pollinose vittae on anterior half in some lights with thin brownish pollen, pile long and brownish-yellow. Pleura thinly grayishbrown pollinose, yellow pilose. Scutellum shining, pile mixed with short and long yellowish hairs, fringe short and yellow. Wing ( Fig. 59C): Hyaline, stigma yellowish-brown, microtrichose, only partially bare on cell bm; calypter wholly brownish; plumula yellow, halter black, capitulum reddish. Legs ( Fig. 59C): Black, all tibia reddish on basal 1/4 to 1/3, femur reddish apically, but there is no sharp demarcation of colors; pile sparse and pale. Abdomen ( Fig. 59B): Opaque black, shining area along sides somewhat resembling elongate side maculae; pile long and yellow on sides, very short, black and appressed on discs; sterna black shining; male genitalia: back, yellowish pilose, surstylus in lateral view ( Fig. 60A) with dorsal margin slightly concave and ventral margin slightly convex, shorter than broad; hypandrium in ventral view ( Fig. 60C) narrowed laterally towards the apex; aedeagal lobe in ventral view ( Fig. 60C) circular, apex rounded; apex of hypandrium (superior lobes) feline claw shape.

FEMALE ( Figs 59D–F, 60D–E). Similar to male except for usual sexual dimorphism, differing on each side of the ocellar triangle with a shining spot devoid of pollen and pile. Frontal wide with pile black with a few pale hairs in the triangular side dust maculae. Mesonotal pile shorter and paler; in front of scutellum brownish pollen can be observed in certain lights. Two pale setulose hairs on scutellum rim. Legs sometimes somewhat more reddish.

Taxonomic notes. Argentinomyia opaca is similar in appearance to A. jalcaensis sp. nov., but differs from them by having the face slightly produced; oral opening about 1.5 times as long as wide ( Figs 59A, C, D, F); scutum yellow pilose; halter black ( Figs 59 B-C, E-F). Based on males A. opaca differs from A. jalcaensis sp. nov. in having the hypandrium in ventral view ( Fig. 60C) narrowed laterally towards the apex [versus hypandrium acute laterally towards the apex in A. jalcaensis sp. nov. ( Fig. 38C)]; apex of hypandrium (superior lobes) feline-claw shaped ( Fig. 60C) [versus apex of hypandrium no-feline -law shaped, with a lateral rounded extension in A. jalcaensis sp. nov. ( Fig. 38C)]. Argentinomyia opaca also resembles A. crenulata and A. rugosonasa , but it is distinguished from by the surstylus in lateral view ( Fig. 60A) with dorsal margin slightly concave and ventral margin slightly convex (versus surstylus with dorsal and ventral margins approximately of the same width in the whole length in A. crenulata ( Fig. 27A); surstylus triangular-like in A. rugosonasa ( Fig. 70A)] (see “diagnosis” under each species or key).

Comments. The Holotype specimen of R. opaca is currently in the AMNH. Photos are available on their website AMNH: https://sci-web-001.amnh.org/imulive/iz.html?#details=ecatalogue. 10021710.

Biology. Label data and field observations suggest that A. opaca visits flowers of Bidens pilosa and Diplostephium rosmarinifolium ( Asteraceae ).

Geographical range. Argentinomyia opaca (n= 40) is distributed in both slopes of the Central cordillera in Colombia * (Antioquia, Caldas, Tolima) and Ecuador (El Tambo, Pichincha, Urbina) ( Fig. 90D). The species is endemic to the Northern Andes domain at middle and high altitudes (2810–3650 m) in the provinces: Cauca (2810– 3650 m) and Magdalena (3200 m).

Non-type material examined. COLOMBIA. Antioquia, Belmira, Páramo de Belmira, 6.707065, -75.714136, 3057 m, Net , 5.iii.2009, A.L. Montoya (1♁, CEUA 95295 ) ; Laguna Montañitas, 6,631 925, -75,648436, 3200 m, Van Someren-Rydon (VSR) Fish , 4-10.x.2011, J. D. Castaño; C. Bota (1♁, CEUA 93133 ) ; Belmira, Páramo Santa Inés, Cabaña Cabildo Verde , El Morro-Alto de La Gallina , 6,632 639, -75,645267, 3200 m, Páramo , ex Diplostephium rosmarinifolium, Net , 4-14.xii.2016, A. L. Montoya; J. Torres; J. P. Carmona (1♁, CEUA 95116 ) ; ex Bidens pilosa, Net , 4-14.ii.2017, A. L. Montoya; C. Rodríguez; J. D. Carmona (2♁, CEUA 95281 ) ; Pan trap blue, 4-14.xii.2016, A. L. Montoya; J. Torres; J. P. Carmona (1♁, CEUA 95464 ) ; …, 637851, -75,662949, 2879 m, Grassland, Net , 16-27.ix.2017, A. L. Montoya; Y. Cardona (1♀, CEUA 103254 ) ; San José de la Montaña, Vereda El Congo , Sector La Laguna , 6,768 593, -75,712085, 2995 m, Grassland , Net , 4-14.xii.2016, C. Henao; A. F. Sepúlveda (1♁, CEUA 95202 ) ; …, 6,763 791, -75,701738, 3117 m, Páramo, Malaise canopy, 4-14.ii.2017, C. Henao; A. F. Sepúlveda (1♀, CEUA95203 ) ; …, Net , 4-14.ii.2017, C. Henao; A. F. Sepúlveda (1♀, CEUA95205 ) ; …, Malaise , 21- 30.vi-5.iv.2017, A. L. Montoya; A. F. Sepúlveda (3♀, CEUA 98017 ) ; 6,768 593, -75,712085, 2995 m, Grassland, Net , 4-14.xii.2016, C. Henao; A. F. Sepúlveda (1♁, CEUA 95204 ) ; 21- 30.vi-5.iv.2017, A. L. Montoya; A. F. Sepúlveda (2♀, CEUA 98072 ) ; Caldas, Villamaría, vía al Nevado de Ruiz, 5,002 008, -75,326819, 3600 m, Net , 19.ii.2006, B.J. Thompson and F.C. Thompson (1♁, 1♀, USNM ENT 00035707-08 ) ; Tolima, Laguna Negra, 4,980 333, -75,335167, 3845 m, Net , 19.ii.2006, B.J. Thompson and F.C. Thompson (1♁, USNM ENT 00035692 ) . ECUADOR. El Tambo , Canar, -2.508088, -78.924898, 2800-2990 m, 3.vii.1965, Pena, Det. J.R. Vockeroth (2♁, 1♀, CNC DIPTERA 112211–13 ) ; Pichincha, Quito, Cutuglagua , -0.281226, -78.534496, 2810 m, 7.v.2001, D. Alvarado (1♀, QCAZ) .