Atrichopogon (Atrichopogon) tricuspis Rossi, Marino & Spinelli, 2025

Atrichopogon (Atrichopogon) tricuspis Rossi, Marino & Spinelli , n. sp.

( Figs 1 View FIG ; 2 View FIG ; 8A View FIG ; 9A View FIG )

urn:lsid:zoobank.org:act:0BBB3F1B-54FE-4424-A9DC-9409451B5D92

TYPE MATERIAL. — Holotype. Peru • ♂; Cuzco, Pagoreni; VII.2004, J. Williams; light trap; MLPA.

Allotype. Peru • ♀; same data as for holotype; MLPA.

Paratypes. Peru • 4 ♂, 8 ♀; same data as for holotype; MLPA • 1 ♀; Cuzco, Kirigueti ; VII.2004; J. Williams; light trap; MLPA .

ETYMOLOGY. — The name tricuspis refers to the three points at apex of the dorsal portion of male aedeagal-parameral complex.

DISTRIBUTION. — Atrichopogon (A.) tricuspis Rossi, Marino & Spinelli , n. sp. is known only from two localities in the Cuzco province (Kirigueti, 11°38’13”S, 73°07’07”W, 395 m, and Pagoreni, 11°42’21.9”S, 72°54’21.9”W, 510 m).

DIAGNOSIS. — Only extant species of Atrichopogon in the New World with pigmented wings and without secondary sexual dimorphism, with the scutum lacking a lateral suture and its posterior margin bearing a pair of bunches of 22-24 short setae, each on stout rounded base. Male: antenna similar to female, dorsal portion of aedeagalparamere complex forming a posteriorly-directed trident. Female: spermatheca heavily sclerotized.

DESCRIPTION

Male adult ( Figs 1 View FIG ; 8A View FIG )

Head ( Fig. 1A View FIG ). Dark brown. Ommatidia ( Fig. 1B View FIG ) with interfacet spicules, broadly abutting medially for length of seven ommatidia. Antenna light brown with plume setae not developed; flagellomeres separate, 1-8 vasiform, 9-13 elongated, proportions as shown in Figure 1A View FIG ; flagellomere 13 with apical nipple, not basally constricted; AR 1.02-1.16 (1.07, n=5). Maxillary palpus ( Fig. 1C View FIG ) pale brown; third segment slender, with well developed pit just beyond midlength; segments 4, 5 separate; segment 5 conical; PR 2.00-2.20 (2.10, n=5). Head width/mouthparts length 3.13-3.53 (3.33, n=5).

Thorax. Dark brown except scutellum yellowish brown. Scutum ( Fig. 1D View FIG ) with all setae in dark pits; without lateral suture. Posterior margin of scutum with pair of bunches of 22-24 short setae, each on stout rounded base. Paratergite with one stout seta. Anepisternum narrow, slightly bilobed posteriorly. Legs light brown. Hind tibia expanded only at apex. Hind tibial spur length less than width of hind tibia at midlength; hind tibial comb with 8-11 spines; prothoracic TR 3.33-4.00 (3.66, n=5), mesothoracic TR 3.14-3.67 (3.32, n=5), metathoracic TR 2.66-3.14 (3.01, n=5); claws curved, moderately stout, bifid at tip; empodia present. Wing ( Fig. 1E View FIG ) with two slight dark spots in area of r-m and in r 3 posterior to apex of R 3; with macrotrichiae on membrane in apical portion of r 3, scarce or no macrotrichiae in m 1; both radial cells well formed, second radial cell three × longer than first; wing length 0.90-0.98 (0.94, n=5) mm; width 0.40-0.42 (0.40, n=5) mm; CR 0.69-0.74 (0.70, n=5). Halter pale.

Abdomen ( Fig. 1F View FIG ).Tergites 1-3 dark brown, 4-7 successively lighter, 8 entirely dark brown. Genitalia ( Figs 1G View FIG ; 8A View FIG ) large, segment 9 about equal in width to segment 8; tergite 9 moderately elongate, extending to about level of apex of gonocoxites; posterior margin rounded. Sternite 9 with posterior margin broadly concave, with row of setae separated medially. Gonocoxite without medial lobe, twice as long as greatest breadth. Gonostylus tapering from base, 0.80 length of gonocoxite, anterolaterally flattened, gently curved, apex pointed with large subapical flange. Aedeagal-parameral complex elongate, broad; dorsal portion forming a posteriorly-directed trident, its mesal point truncate, lateral ones pointed; ventral portion somewhat rounded posteriorly, with lateral arms directed laterally. Cercus slender, elongate, extending beyond margin of tergite 9.

Female adult ( Figs 2 View FIG ; 9A View FIG )

Head. As for male, with following differences: proportions of flagellomeres as shown in Figure 2A View FIG , flagellomeres 1-8 brown, slightly longer than broad, vasiform, flagellomeres 9-13 elongated; AR 1.39-1.51 (1.45, n=9). Maxillary palpus as in Figure 2B View FIG , basal 2/3 of third segment slightly swollen with shallow sensory pit near midlength; segments 4, 5 separate, its combined length longer than third segment; PR 2.18-2.50 (2.29, n=9); head width/mouthparts length 2.70-3.13 (2.86, n=9). Mandible poorly developed, without teeth.

Thorax. Legs with hind tibial comb with 9-11 spines; prothoracic TR 3.43-3.83 (3.68, n=9), mesothoracic TR 3.28-3.71 (3.46, n=9), metathoracic TR 2.70-3.33 (3.05, n=9); claws curved, not bifid at tip. Wing ( Fig. 2C View FIG ) with the same pattern of pigmented membrane, with numerous macrotrichiae in r 3, scarce in m 1; radial cells narrow, second 3.5 × longer than first; wing length 0.98-1.08 (1.02, n=9) mm; width 0.42-0.48 (0.45, n=9) mm; CR 0.69-0.72 (0.70, n=9).

Abdomen ( Fig. 2D View FIG ). Tergites 1-7 brown, segments 8-10 dark brown. Sternite 7 rectangular. Sternite 8 without elongate cuticular extensions, posterior margin boat-shaped. Sternite 9 ( Figs 2E View FIG ; 9A View FIG ) subquadrangular, sclerotized anteriorly. One spermatheca heavily sclerotized, ovoid with short, slender neck, measuring 0.090 -0.110 (0.100, n=5) by 0.064 -0.080 (0.070, n=5) mm. Cercus brown.

REMARKS

Borkent & Picado (2004) pointed out that the lack of a lateral scutal suture, shared by A. asuturus Borkent & Picado, 2004 and A. tirzae Borkent & Picado, 2004 , both from Costa Rica, is a condition apparently unique within at least the Forcipomyiinae Lenz, 1934 , and it is likely a synapomorphy for these two species. Atrichopogon tricuspis Rossi, Marino & Spinelli , n. sp. shares the same condition with the two species mentioned before. The presence of setae arising from dark pits on the scutum is shared with A. asuturus , A. tirzae and A. beccus Borkent & Picado, 2004 and may be a synapomorphy of these four species; however, these pits are less developed, as in A. beccus . Furthermore, this new species shares with A. asuturus and A. tirzae the presence of femalelike antenna (five flagellomeres elongated) and wing, the main differences between these species being in male genitalia. The aedeagal-parameral complex of A. tricuspis Rossi, Marino & Spinelli , n. sp. is elongate with the dorsal portion forming a posteriorly-directed trident, and the gonostylus ends in a pointed tip. The aedeagal-parameral complex of A. tirzae bears a posteriorly-directed prong, while in A. asuturus the dorsal portion tapers somewhat rounded. The apex of the gonostylus of both species is bifid.

During the present study we examined the female holotype of A. nubeculosus Macfie, 1949 a species with pigmented wings known from Mexico. It shares with A. tricuspis Rossi, Marino & Spinelli , n. sp. the pair of bunches of short setae on the posterior margin of the scutum, and this condition is likely a synapomorphy for these two species. However, the spermatheca of A. nubeculosus is very hyaline, nearly imperceptible, contrasting with the heavily sclerotized spermatheca of A. tricuspis Rossi, Marino & Spinelli , n. sp. The male of A. nubeculosus is unknown.