Argentinomyia jalcaensis Thompson & Montoya sp. nov.

Proposed standard English name: Jalca’s long-antennae flower fly.

Tuberculanostoma 08-08 Thompson, unpublished

(Figs 37, 38 and 91C)

Type material. HOLOTYPE. Adult male, pinned, deposited at Natural History Museum of Denmark, Copenhagen. Original label: “PERÚ, Santana, Áncash, 22: 35 km southeast of Huaraz, Cerro Cahuish” / “ -9.383915, -77.651629, 4100 m, Quabrado Pucaudao” / “ 15-18.ii.1987, O. Karsholt ”. “HOLOTYPE / Argentinomyia jalcaensis / Thompson & Montoya 2023”.

Length (n= 1): Body, 6.5 mm; Wings, 5.4 mm.

Diagnosis. Generally metallic bluish-black fly. Face slightly produced; oral opening about 1.5 times as long as wide; antenna black; scutum yellow pilose; halter black; legs except pro- and mesotibiae yellow on apical 1/5 and basal 1/3, yellow pilose. Hypandrium acuted laterally towards the apex; apex of hypandrium (superior lobes) no feline claw shape.

Description. MALE. Head (Fig. 37A): Face only slightly produced anteriorly, about 1/2 as long anteriorly as high dorsally, sparsely white pollinose laterally, shiny on medial 2/3, white pilose laterally; oral opening about 1.5 times as long as wide; gena black, shiny, silvery-white pollinose, yellow pilose; tubercle distinct, only slightly dorsal to oral margin; lunule black; frontal triangle broad, sparsely white pollinose laterally, shiny anteromedially, black pilose; occiput silvery-white pollinose and yellow pilose and pollinosity, sparser on dorsal 1/4, with some longer black cilia on dorsal 1/4. Antenna black, short, about half as long as face, ratio 1.0:1.0:1.6; basoflagellomere oval, slightly longer than broad; arista about 1.2 times as long as basoflagellomere. Thorax (Figs 37B–C): Postpronotum sparsely white pollinose; scutum shiny, long yellow pilose; scutellum shiny, yellow pilose; pleuron sparsely white pollinose, yellow pilose. Wing (Fig. 37C): Hyaline, stigma brownish yellow, microtrichose; calypter white; plumule white; halter black, capitulum white. Legs (Fig. 37C): Black, except pro- and mesotibiae yellow on apical 1/5 and basal 1/3, yellow pilose; coxae and trochanters silvery-white pollinose, white pilose; profemur without bristles; metatarsus with apical tarsomeres black pilose. Abdomen (Fig. 37B): Subshiny, dull black laterally in form of large elongate areas on lateral 1/4 reaching to apical 1/4, dull black pollinose medially and apically, long yellow pilose except shorter medially; sterna shiny, yellow; male genitalia: Black, small, yellow pilose, surstylus in lateral view (Fig. 38A) shorter; hypandrium in ventral view (Fig. 38C) acuted laterally towards the apex; apex of hypandrium (superior lobes) no feline claw shape, with a lateral rounded extension (Fig. 38C); aedeagal lobe in ventral view (Fig. 38C) circular, apex rounded.

FEMALE. Unknown.

Etymology. The specific epithet “ jalcaensis ” is derived from the ecoregion name where the species was found in the Peruvian Andes and the Latin suffix - ensis denoting place, locality, country, or belonging to, pertaining to (Brown 1956: 45, 303). The “ Jalca ” is defined in its broadest sense as the shrubby or prairie, humid or sub-humid mountain range, located between 4,800 to 6,768 meters above sea level (Height of Huascarán) (Sonter et al. 2018).

Taxonomic notes. Argentinomyia jalcaensis sp. nov. is similar in appearance to A. opaca, from which it differs in having the following combination of characters: Generally metallic bluish-black. Face slightly produced; oral opening about 1.5 times as long as wide; antenna black (Figs 37A, C, D-F); scutum yellow pilose; halter black (Figs 37 B-C, E-F); legs except pro- and mesotibiae yellow on apical 1/5 and basal 1/3, yellow pilose (Figs 37A, C, DF). Argentinomyia opaca is characterized by the face perpendicular with a well-rounded tubercle, deeply concave dorsally (Figs 59A, C, D-F); scutum black pilose; halter white (Figs 59 B-C, E-F); legs black, black pilose (Figs 59A, C, D-F). Based on males, A. jalcaensis sp. nov. differs from A. opaca in having the hypandrium in ventral view (Fig. 38C) acuted laterally towards the apex [versus hypandrium narrowed laterally towards the apex in A. opaca (Fig. 60C)]; apex of hypandrium (superior lobes) no feline claw shape, with a lateral rounded extension (Fig. 38C) [versus apex of hypandrium feline claw shape in A. opaca (Fig. 60C)] (see “differential diagnosis” under each species or key).

Distribution. Argentinomyia jalcaensis sp. nov. (n= 1) is exclusively distributed in the highlands (4100 m) of the Cordillera Occidental and Central Sur in Perú, which corresponds to the Central Andes domain, Puna province (Fig. 91C). The species is restricted to high-elevation Jalca grassland of Cerro Cahuish in Perú, which raises the need for further expeditions to neighboring areas of the type locality, in order to discover and describe the female specimens as well as to know its population dynamic and conservation status.

Conservation status. Unfortunately, the region where A. jalcaensis sp. nov. inhabits is near the Pierina gold and silver open-pit mine, located in the Callejón de Huaylas in the Peruvian Andes (Cordillera Negra of northcentral Perú), approximately 10 kilometers directly north of Huaraz at a height of 4100 meters. Since mining has the potential to produce serious and specific threats to biodiversity, with intensive land use that severely fragments and declines the extension and quality of the habitat due to deforestation (see Sonter et al. 2018; Montoya et al. 2021), with the loss of connectivity by the reduction of functional conservation corridors, we consider that populations of A. jalcaensis sp. nov. is probably “Near Threatened”, “Endangered” or “Vulnerable”, since it occupies small range, threatened by several human threats. In this sense, we suggest that this species should be studied and its level of threat evaluated, taking into account the conservation criteria of the International Union for Conservation for Nature—IUCN, considering the restricted distribution to a unique habitat such as the Jalca, where the impact of gold and silver mining could cause its disappearance in the coming years, making the need to encourage conservation efforts as has suggested for species Copestylum enriquei Montoya, Parada-Marín & Ramos-Pastrana, 2022 in the Amazonian region (Montoya et al 2022).