Zygomyia acrotricha Kurina & Õunap 2023, sp. nov.

(Figs 1D, 3A–E, 19A)

urn:lsid:zoobank.org:act: 3D9C938C-1274-4907-A018-5F565222D362

Type material. HOLOTYPE ♂, ECUADOR, Napo Province, Yanayacu Biological Station, 0.5956S 77.8942W, alt. 2234 m, 29.viii–3.ix.2019, X. Mengual, T. Salden leg., double Malaise trap (mounted from alcohol with terminalia in glycerine, INABIO; specimen code: MECN-EN-DIP-4858; one fore leg used for DNA extraction, GenBank accession number: OP747420). PARATYPE ♂, same as holotype (mounted from alcohol, ZFMK).

Diagnosis. Zygomyia acrotricha is distinguishable by the undulating posteroventral margin of the gonocoxites with medial and lateral convexities, and the gonostylus with both ventral and dorsal branches bearing posteriorly a row of pointed megasetae.

Description. Male (n = 2). Body length 2.5 mm. Wing length 2.2–2.3 mm; ratio of length to width 2.77–2.80.

Head. Dark yellow with numerous dark setae. Two ocelli close to eye margins. Clypeus yellow, somewhat lighter than head. Mouth-parts yellow. Palpus with all segments light brown, ratios of three apical segments 1:1.29:2.14. Scape, pedicel and basal half of first flagellomere yellow, other flagellomeres light brown. Flagellomeres cylindrical, first flagellomere 2.4 × as long as broad, fourth flagellomere 1.6 × as long as broad, apical flagellomere conical, 3.4 × as long as broad basally. Flagellomeres with short yellowish setae.

Thorax. Mesonotum dark yellow. Pleural parts yellow. All bristles and setae on thorax brown. Scutellum with marginal setae, including four strong bristles. Antepronotum with setae, including 6–8 bristles of different lengths. Proepisternum with setae including 4–5 stronger bristles. Anepisternum with a number of posteriorly-directed short setae and 5–6 bristles of different lengths on dorsal part. Anepimeron with short setae and 2 bristles on dorsal part. Laterotergite with 5–8 dorsally-directed setae at hind margin. Metepimeron with 6–7 setae on posterior part. Halter yellow. All legs entirely yellow. Tarsi appear darker, due to dense brown setation. Whole anterior side of fore coxa, apical fourth of anterior side of mid coxa and all femora clothed in dark setae. Hind coxa with 4–5 setae on posterior side apically. Mid femur with 1–2 apicoventral bristle, hind femur with 3–4 apicoventral bristles. Mid tibia with 2 a, 4–5 d (progressively longer towards apex), 3 p and 1 v (one additional short seta can present). Hind tibia with 7 a, 4–5 d (progressively longer towards apex) and 6 short posterior setae. Length ratio of femur to tibia for fore, mid and hind legs: 1.15–1.18, 1.07, 0.83–0.85. Length ratio of tibia to basitarsus for fore, mid and hind legs: 1.10–1.17, 1.40–1.48, 1.51–1.55. Wing membrane with very light brownish tinge but without distinct markings. Veins light brown. R 1 and R 4+5 with strong setae on both sides. Crossvein rm and bM-Cu glabrous. Dorsal surfaces of M 1 and M 2 with setae along apical 2/3. CuA with 5–6 apical setae on dorsal surface. rm somewhat shorter than m-stem. Costa not extending beyond R 4+5.

Abdomen. Light brown. Terminalia (Figs 3A–E, 19A) yellow to light brown. Posteroventral margin of gonocoxites undulating with medial and lateral convexities. Ventral branch of the gonostylus transversally extended, with (1) ventral digitate lobe bent dorsad sub-apically, bearing row of pointed megasetae along posterior margin, (2) dorsal lobe spathulate, bearing row of pointed megasetae with projecting sockets along posterior margin, and (3) two pointed megasetae and small digitate lobe with two setae apically on a more dorsal level between ventral and dorsal lobes. Dorsal branch of the gonostylus rostrum-shaped, with (1) anterior small, sub-rounded, setose lobe, (2) posteromedial corner drawn medially out to pointed process, and (3) row of pointed and curved megasetae along posterior margin. Aedeagus apically bifurcate. Parameres with apical part conical, somewhat extended over aedeagus posteriorly. Gonocoxal apodemes large, arched anteriorly, broadly conical apically.

Female. Unknown.

Etymology. The specific epithet is derived from Greek, akros [at the tip] and thrix [hair], referring to the numerous megasetae at the posterior margin of the gonostylus.