Zygomyia bicolor Edwards, 1934

Kurina, Olavi & Õunap, Erki, 2023, Morphological and molecular data reveal fifteen new sympatric Zygomyia Winnertz, 1864 (Diptera: Mycetophilidae) species from Ecuador, Zootaxa 5227 (1), pp. 1-49 : 35

Zygomyia bicolor Edwards, 1934

( Figs 2C , 18A–E , 20D )

Material studied. 1 ♂, 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-4873; one fore leg used for DNA extraction, GenBank accession number: OP747421 ) .

Diagnosis. Distinguished by a combination of characters including central and apical darkenings on the wing and light brown mesonotum. Ventral branch of the gonostylus is about as long as wide and has a medially directed simple megaseta on posterior margin internally. Posteriorly bifurcate dorsal branch of the gonostylus has lateral prong of apical furca digitate and medial prong beak-shaped, apically pointed.

Redescription. Male (n = 1). Body length 2.4 mm. Wing length 2.3 mm; ratio of length to width 2.52.

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 1:1.38:2.00. Scape, pedicel and flagellomeres light brown, except first flagellomere basally yellow. Flagellomeres cylindrical, first flagellomere 1.8 × as long as broad, fourth flagellomere 1.3 × as long as broad, apical flagellomere conical, 3.0 × as long as broad basally. Flagellomeres with short yellowish setae.

Thorax. Mesonotum dark yellow. Pleural parts yellow with dorsal and posterior margins of anepisternum and posterior margin of laterotergite brown. All bristles and setae on thorax brown. Scutellum with marginal setae, including four strong bristles. Antepronotum with setae, including 7–8 bristles of different lengths. Proepisternum with setae including 4 stronger bristles. Anepisternum with a number of posteriorly-directed short setae and 4 bristles of different lengths on dorsal part. Anepimeron with short setae and 2 bristles on dorsal part. Laterotergite with 6 dorsally-directed setae medially. Metepimeron with 8 setae on posterior part. Halter yellow. Legs yellow, except hind femur apically brown. 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 3 apicoventral bristles of different size, hind femur with 4–5 apicoventral bristles of different size. Mid tibia with 2 a, 6 d (progressively longer towards apex), 2 p and 3 v (2 very long setae + one additional short seta). Hind tibia with 8 a, 5 d (progressively longer towards apex) and with row of posterodorsal short setae. Length ratio of femur to tibia for fore, mid and hind legs: 1.33, 1.05, 0.89. Length ratio of tibia to basitarsus for fore, mid and hind legs: 1.15, 1.48, 1.68. Wing membrane with large indistinct preapical brown marking including tip of R 1, extending vaguely to M 1 and with indistinct central marking over Rs and r-m. 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 whole length. CuA with 3–4 apical setae on dorsal surface. rm somewhat shorter than m-stem. Costa not extending beyond R 4+5.

Abdomen. Dark brown with first two segments laterally lighter. Terminalia ( Figs 18A–E , 20D ) yellow to light brown. Posteroventral margin of gonocoxites broadly concave, with serrated fringe dorsally. Posterior ⅔ of gonocoxite tightly setose with setae of similar size. Ventral branch of the gonostylus short, about as long as wide, with (1) posteromedial corner drawn medially out, setose, with 2–3 deviating long setae, (2) medially directed simple megaseta on posterior margin internally. Dorsal branch of the gonostylus posteriorly bifurcate, with (1) anterior part slightly longer than wide, (2) 2–3 stronger setae anteromedially, (3) lateral prong of apical furca digitate, setose, (4) medial prong of apical furca beak-shaped, apically pointed, with short setae along medial margin.Aedeagus apically widening, with rounded apical margin. Parameres apically rounded, extending slightly over aedeagus posteriorly. Gonocoxal apodemes large, apically widening.

Female. Unknown.

Remarks. In spite of having some small differences, the male terminalia of the studied specimen match generally with those figured by Lane (1948: fig. 3) and Lane (1951: fig. 2) for Z. bicolor . Also the figures by Lane are somewhat different between each other, especially in outline of the dorsal branch of the gonostylus. However, this is obviously caused by different angle of view; as observed in Ecuadorian material of Zygomyia , the angle of study is significant for interpreting the outline of branches and lobes of the male gonostylus. The conspecificity of studied specimen with Z. bicolor is well supported also by wing pattern.

Figures

FIGURE 2. Habitus of Zygomyia species from Ecuador (all photos, except Z. bicolor, are taken from holotypes). A, Z. spinosa sp. nov.; B, Z. ximoi sp. nov.; C, Z. bicolor Edwards, 1934 (MECN-EN-DIP-4873); D, Z. uniordata sp. nov.; E, Z. napoensis sp. nov.; F, Z. trilobata sp. nov.; G, Z. triseta sp. nov.; H, Z. talpaeforma sp. nov. Scale bars = 1 mm.

FIGURE 18. Zygomyia bicolor Edwards, 1934, male terminalia (MECN-EN-DIP-4873). A, B, ventral view; C, posterior view; D, dorsal view; E, gonostylus, dorsal view. Scale bar = 0.05 mm (A–D) and 0.02 mm (E).

FIGURE 20. Aedeagal apparatus of Zygomyia species from Ecuador (all photos, except Z. bicolor, are taken from holotypes). A, Z. comata sp. nov.; B, Z. geniculata sp. nov.; C, Z. longistyla sp. nov.; D, Z. bicolor Edwards, 1934 (MECN-EN-DIP-4873); E, Z. triseta sp. nov.; F, Z. talpaeforma sp. nov. Scale bar = 0.1 mm.