Leptoconops (Leptoconops) brasiliensis (Lutz)

(Figures 1–2)

Tersesthes brasiliensis: Lutz, 1913: 66 (female; Brazil); Gezuelo and Franca-Rodríguez, 1972 (Uruguay record).

Leptoconops brasiliensis: Lane, 1945: 358 (new comb.; type redescr.)

Leptoconops (Leptoconops) brasiliensis Cavalieri & Chiossone, 1966: 56 (in key to American species); Ronderos & Spinelli, 1992: 43 (in key to Neotropical species); Borkent & Spinelli, 2000: 9 (in Catalog; distrib.); Trindade & Gorayeb, 2005: 66 (Pará State — Brazil); Spinelli et al., 2005: 148 (Argentina record); Borkent & Spinelli, 2007: 44 (in Neotropical catalog); Pessoa et al., 2012: 138 (Acre State, Brazil); Farias et al., 2015: 3 (Amazonas State, Brazil); Borkent & Dominiak, 2020: 38 (in World Catalog); Spinelli et al, 2022: 489 (in key to Neotropical species); Santarém & Felippe-Bauer, 2023: 48 (Brazilian biting midges Catalog; distribution); Spinelli et al., 2023: 8 (Argentina record removed).

Diagnosis. The only species of Leptoconops (Leptoconops) on Neotropical region with the following combination of characters: frons with a pair of mesal setae; 3 rd palpal segment slightly longer than 4 th; costa extending to 0.45–0.52 of total wing length, longitudinal veins reaching wing margin; two ovoid spermathecae. Male unknown.

Redescription. Female. Head. Dark brown. Eyes (Fig. 1A) bare, separated by a distance equal to 0.33–0.38 (0.35, n=3) of total head width, separation approximately to diameter of ten ommatidial facets; vertex with long setae, frons with a pair of mesal setae (Fig.1A), clypeus usually bare or with two setae. Antenna (Fig. 1B) with pale scape, pedicel and flagellum dark brown with 12 flagellomeres, lengths of flagellomeres in proportion of 35-20-20- 20-20-20-20-20-20-23-23-75 μm; last flagellomere 2.54–3.77 (3.24, n=4) longer than broad; AR 0.74–0.87 (0.80, n=5). Palpus (Fig. 1C) dark brown, lengths of segments in proportion of 40 (I+II)-53-42 μm; 3 rd segment elongated with broad, shallow, irregular sensory pit extending for most of its length; PR 2.0–3.43 (2.76, n=4). Mandible with 13 small teeth, P/H ratio 0.58–0.62 (0.60, n=2).

Thorax. Dark brown; scutellum not visible in slide mounted specimens. Legs (Fig. 2C) uniformly dark brown; basitarsi and tarsomeres 2 paler (Fig. 2D); hind tibial comb (Fig. 2E) with 4 spines (n=4), the first near the spur smaller, delicate and hyaline; first to fourth from the spur measuring 22.5–27.5 (25, n=2), 30–47.5 (40.5, n=5), 37.5–45 (39.5, n=5), 27.5–37.5 (32, n=5) μm. Tarsi (Fig. 2D) with strong ventral spines; a pair of apical spines on tarsomeres 1–3; tarsomeres 4 can present one apical spine; tarsal claws (Fig. 2F) short, slightly curved, 0.40 (n=3) as long as 5 th tarsomeres, with basal bristly hairs (Fig. 2F). Wing (Figs. 2A–B) membrane infuscated, microtrichia abundant, stigma pale brown; longitudinal veins reaching wing margin; wing length 0.69–0.83 (0.77, n=5) mm, width 0.33–0.40 (0.37, n=5) mm; costa extending to 0.45–0.52 (0.48, n=5) of total wing length. Halter pale.

Abdomen. Brown. Genital lamellae (Fig. 2G) brown, long, narrow, about 5x longer than broad, 3x longer than sternite 9. Sternite 8 (Fig. 2I) with two-three pair of long hairs. Spermathecae (Fig. 2H) two, ovoid, subequal, measuring 30.0–42.5 (36.2, n=4) by 25.0–32.5 (28.7, n=4) μm and 32.5–45 (36.2, n=4) μm by 27.5–30.0 (28.7, n=2) μm; sclerotized necks short with 5 (n=3) μm.

Male. Unknown.

Material examined. Type series, 3 females, slide mounted, labeled “ Tersethes brasiliensis Lutz (1913), Rio Tocantins, Pará, BRASIL, 1912 [Astrogildo Machado col.].” (CCER # T335 /1.3 - T335 /3.3); 1 female, slide mounted, labeled “ Uruaçú, Goiás, BRASIL, 13.III.2000 ” (CCER#3833); 1 female same data except 14.III.2000 (CCER#3834); 1 female same data except 17.IV.2000 (CCER#3835) (NEW RECORD).

Distribution. Brazil (Acre, Amazonas, Pará, Goiás) and Uruguay.

Taxonomic discussion. Leptoconops (L.) brasiliensis is a typical member of the Leptoconops subgenus by the frons with a pair of setae, claws with a basal bristle, tarsi with strong ventral spines and female genital lamellae long. From the seven Neotropical species, it is similar to L. (L.) casali Cavalieri & Chiossone by the antennal flagellomeres shape, the aspect of the palpal sensory pit, the costa reaching 0.40–0.50 from total wing length and the ovoid spermathecae. These species can be easily distinguished from each other by the smaller wing length (1.24 in L. (L.) casali), the palpus with segment 3 only slightly longer than 4 (1.5x longer in L. (L.) casali) and longitudinal veins extending to the wing margin (obsolete in L. (L.) casali). Ronderos & Spinelli (1992) and Spinelli et al. (2022) consider in their key that L. (L.) brasiliensis has bare frons; however, we observe that the specimens present a pair of medial setae in the frons (Fig. 1A). In addition, these authors cited the flagellomere 12 of female antenna 4–5 times longer than broad, but herein we observe this relation much smaller. In this case, we have seen that the antenna position after slide montage and the conservation state of the material is very important and can influence this relation. Considering this, we suggest not using this measurement to separate and define species from this subgenus.

In 2005, Trindade & Gorayeb corrected the record of the type locality for the state of Pará and collected this species in the estuarine coastal zone and on the coast of this same state. Pessoa et al. (2012) found it on the river margin in the state of Acre. Farias et al. (2015) collected in the Amazonas State, near small farms, but there is no data describing if it was collected in upland or lowland environments. Spinelli et al. (2005) have reported L. (L.) brasiliensis from Argentina, but recently Spinelli et al. (2023) recognized the specimen is L. (L.) casali and removed the record. We report this species for the first time in the Brazilian State of Goiás, in Uruaçú municipality, which is in the Cerrado biome.This region includes one of the largest artificial lakes associated with a hydroelectric plant in Brazil. Thus, we can observe that L. (L.) brasiliensis occurs in areas with high humidity, even if they are not coastal areas, as it was previously reported. It is the only species from this subgenus found in Brazil.