Zygomyia, Winnertz, 1864

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 : 3-5

Key to the Neotropical species of Zygomyia

The following key of the Neotropical Zygomyia species is compiled largely on the basis of characters in male terminalia. The previous key published by Lane (1951) and the original descriptions including figures of male terminalia are used for covering species described prior to this study. However, the coloration of head, thorax and abdomen, i. e. the characters involved mainly by Lane (1951), are found somewhat variable in the Ecuadorian material and are thus not adopted as key characters as far as possible. Two species – Z. aurantiaca Edwards, 1934 and Z. modesta Lane, 1948 – are omitted. Zygomyia aurantiaca is known only from female type material from Costa Rica, and the figures of male terminalia of Z. modesta ( Lane 1948: figs 11, 57) lack several crucial details. However, the gonostylus of the latter species has been figured in necessary details allowing unambiguous identification. According to coloration, Z. modesta , known only from type material (São Paulo province in Brazil), has been discussed to form a group with four species, viz. Z. golbachi Lane, 1961 , Z. aguarensis Lane, 1951 and Z. herteli Lane, 1951 ( Lane 1961) .

1. Costal vein extending beyond R 4+5 ....................................................................... 2

- Costal vein not extending beyond R 4+5 .................................................................... 3

2. Costal vein extending well beyond R 4+5; very small species, length of body about 1.6 mm; terminalia as figured by Lane (1951: fig 19), with ventral branch of the gonostylus divided by a deep medial notch.................................................................................................. Z. chavantesi Lane, 1951 [ Brazil: Santa Catarina]

- Costal vein extending somewhat beyond R 4+5; length of body about 2.0 mm; ventral branch of the gonostylus simple, not divided by a medial notch ( Fig. 16 ).............................................. Z. uniordata sp. nov. [ Ecuador]

3. Wing hyaline or with homogeneous brownish tinge, but without clear markings................................... 4

- Wing with clear dark markings (e.g. Fig. 1B ).............................................................. 22

4. Mesonotum with distinct brown to blackish markings........................................................ 5

- Mesonotum entirely yellow to blackish brown, but without distinct markings..................................... 6

5. Mesonotum with three distinct and separate dark brown marks; terminalia as figured by Lane (1951: fig. 6)................................................................. Z. brasiliana Lane, 1947 [ Brazil: São Paulo, Santa Catarina]

- Mesonotum with two blackish spots contiguous to scutellum; terminalia as figured by Lane (1951: fig. 7)................................................................................... Z. tapuiai Lane, 1951 [ Brazil: São Paulo]

6. Posteroventral margin of the gonocoxites concave, convex, undulating or with short setose protrusion but without long convoluted outgrowths................................................................................ 7

- Posteroventral margin of the gonocoxites with long convoluted medial outgrowths, more than half length of gonostylus; ventral branch of the gonostylus with five modified megasetae internally ( Fig. 5 ).............. Z. diversiseta sp. nov. [ Ecuador]

7. Posteroventral margin of the gonocoxites conical, widely convex or with medial protrusions......................... 8

- Posteroventral margin of the gonocoxites straight, emarginated or concave...................................... 13

8. Posteroventral margin of the gonocoxites conical or widely convex............................................. 9

- Posteroventral margin of the gonocoxites with delimited medial or medial and lateral protrusions.................... 11

9. Posteroventral margin of the gonocoxites widely convex; ventral branch of the gonostylus without an apical row of prominent spines............................................................................................. 10

- Posteroventral margin of the gonocoxites conical; ventral lobe of the gonostylus large, with a row of prominent spines apically ( Fig. 13 ).................................................................. Z. talpaeforma sp. nov. [ Ecuador]

10. Dorsal branch of the gonostylus with dorsal bifurcate lobe bearing pointed megasetae on both prongs apically ( Lane 1951: fig. 10)................................................... Z. herteli Lane, 1951 [ Brazil: São Paulo, Santa Catarina]

- Dorsal branch of the gonostylus different, with three long apically hooked and two apically haired megasetae at most dorsal position ( Lane 1951: fig. 9)...................................... Z. aguarensis Lane, 1951 [ Brazil: Santa Catarina]

11. Posteroventral margin of the gonocoxites only with a medial protrusion......................................... 12

- Posteroventral margin of gonocoxites deeply undulating with medial and lateral convexities; dorsal branch of the gonostylus rostrum-shaped, with a row of pointed and curved megasetae along posterior margin; aedeagus apically bifurcate ( Fig. 3 )............................................................................. Z. acrotricha sp. nov. [ Ecuador]

12. Posteroventral margin of the gonocoxites with a prominent medial protrusion, densely covered with strong setae; dorsal branch of the gonostylus ovoid, with a sabre-shaped megaseta posterolaterally ( Fig 10 ).......... Z. paniculata sp. nov. [ Ecuador]

- Posteroventral margin of the gonocoxites with a shallow medial protrusion, covered with short setae; dorsal branch of the gonostylus sub-quadrate, with a large aggregation of setae and small spines anteroventrally; aedeagus apically bifurcate ( Fig. 12 )............................................................................................................................................................................. Z. spinosa sp. nov. [ Ecuador]

13. Posteroventral margin of the gonocoxites emarginated or widely concave....................................... 14

- Posteroventral margin of the gonocoxites almost straight; ventral branch of the gonostylus with a comb of 5–6 spines posteromedially ( Fig. 11 )..................................................... Z. pectinella sp. nov. [ Ecuador]

14. The ventral branch of the gonostylus without any megasetae.................................................. 15

- The ventral branch of the gonostylus with at least one long megaseta deviating from other setosity................... 17

15. Ventral branch of the gonostylus elongated, tapering, with two short spines apically; parameres with a group of short spines apicomedially ( Lane 1951: fig. 6).................................... Z. golbachi Lane, 1951 [ Argentina: Tucumán]

- Ventral branch of the gonostylus not elongated, without apical short spines; parameres without spines apicomedially..... 16

16. Ventral branch of the gonostylus wider than long; dorsal branch of the gonostylus three-lobed, with large rostrum-shaped lobe bearing a row of small spines at medial margin ( Fig. 14 ).............................. Z. trilobata sp. nov. [ Ecuador]

- Ventral branch of the gonostylus longer than wide; dorsal branch of the gonostylus two-lobed, with large quadrangular lobe bearing a group of very small spines posteromedially ( Fig. 17 )............................ Z. ximoi sp. nov. [ Ecuador]

17. Posteroventral margin of the gonocoxites slightly concave or emarginated....................................... 18

- Posteroventral margin of the gonocoxites medially broadly and deeply concave; dorsal branch of the gonostylus sub-quadrate with five megasetae of different size and shape at posterior margin ( Fig. 4 )................ Z. comata sp. nov. [ Ecuador]

18. Dorsal branch of the gonostylus complex, with lobes of different size and shape, if one-lobed then elongated and apically bifurcate........................................................................................... 19

- Dorsal branch of the gonostylus simple, obovoid, slightly longer than wide, with two megasetae and a stronger seta posteromedially ( Lane 1951: fig 8)................................ Z. plaumanni Lane, 1951 [ Brazil: Santa Catarina]

19. Ventral branch of the gonostylus bi-lobed with lateral non-setose lobe digitate.................................... 20

- Ventral branch of the gonostylus one-lobed............................................................... 21

20. Ventral branch of the gonostylus with two flame-shaped megasetae medially; dorsal branch of the gonostylus with a large pointed megaseta and a large flame-shaped megaseta at posterolateral margin ( Fig. 6 )....... Z. flamma sp. nov. [ Ecuador]

- Ventral branch of the gonostylus with a pointed megaseta medially; dorsal branch of the gonostylus bent medially at right angle..................................................................... Z. geniculata sp. nov. [ Ecuador]

21. Ventral branch of the gonostylus about as long as wide, with three megasetae, a long hair-like megaseta at anteromedial corner, a digitate megaseta medially and pointed megaseta more laterally at posterior margin ( Fig. 15 )..................................................................................................... Z. triseta sp. nov. [ Ecuador]

- Ventral branch of the gonostylus wider than long, with posteromedial corner drawn out to a digitate membranous process with apical mushroom-shaped formation and a sabre-like megaseta on ventral surface ( Fig. 9 ).... Z. napoensis sp. nov. [ Ecuador]

22. Wing with a dark central spot only...................................................................... 23

- Wing with an apical darkening in addition to a dark central spot............................................... 24

23. m-stem shorter than r-m; dorsal branch of the gonostylus with a club-shaped large megaseta posteriorly ( Lane 1951: fig. 11)................................................................ Z. lafooni Lane, 1951 [ Brazil: Santa Catarina]

- m-stem as long as r-m; dorsal branch of the gonostylus without megasetae ( Lane 1951: fig. 12)..................................................................................... Z. freemani Lane, 1951 [ Brazil: Santa Catarina]

24. Scutum light brown to yellowish........................................................................ 25

- Mesonotum dark brown; ventral branches of the gonostylus with very long setae (Lane 1954: fig.13)................................................................................... Z. heros Lane, 1951 [ Brazil: Santa Catarina]

25. Ventral branch of the gonostylus exceptionally long........................................................ 26

- Ventral branch of the gonostylus about as long as wide...................................................... 27

26. Haltere with yellow stem and blackish knob; ventral branch of gonostylus less than 10 times as long as wide ( Lane 1948: figs 5, 35, 42)...................................... Z. ornatipennis Lane, 1948 [ Brazil: São Paulo, Argentina: Misiones]

- Haltere entirely yellow; ventral branch of gonostylus about 15 times as long as wide...... Z. longistyla sp. nov. [ Ecuador]

27. Mid tibia with one ventral bristle; gonocoxite with a stout seta at posteroventral margin; aedeagal complex ovoid ( Lane 1961: fig. 5)......................................................... Z. argentina Lane, 1961 [ Argentina: Tucumán]

- Mid tibia with two ventral bristles; gonocoxite without deviating setae at posteroventral margin; aedeagal complex parallelsided ( Lane 1948: fig. 3; Lane 1951: fig. 2; Fig. 18 )............................................................................................... Z. bicolor Edwards, 1934 [ Bolivia, Brazil: São Paulo, Santa Catarina; Ecuador]

Figures

FIGURE 1. Habitus of Zygomyia species from Ecuador (all photos are taken from holotypes). A, Z. diversiseta sp. nov.; B, Z. longistyla sp. nov.; C, Z. flamma sp. nov.; D, Z. acrotricha sp. nov.; E, Z. paniculata sp. nov.; F, Z. geniculata sp. nov.; G, Z. pectinella sp. nov.; H, Z. comata sp. nov. Scale bars = 1 mm.

FIGURE 3. Zygomyia acrotricha sp. nov., male terminalia (holotype, MECN-EN-DIP-4858). A, B, ventral view; C, posterior view; D, dorsal view; E, gonostylus, dorsal view. Scale bar = 0.05 mm.

FIGURE 4. Zygomyia comata sp. nov., male terminalia (holotype, MECN-EN-DIP-4859). A, B, ventral view; C, dorsal view; D, posterior view; E, gonostylus, dorsal view. Scale bar = 0.1 mm (A–D) and 0.05 mm (E). Abbreviations: gc = gonocoxite, gc pvm = posteroventral margin of gonocoxite, gst db = dorsal branch of gonostylus, gst vbdl = dorsal lobe of ventral branch of gonostylus, gst vbml = medial lobe of ventral branch of gonostylus, gst vbvl = ventral lobe of ventral branch of gonostylus.

FIGURE 5. Zygomyia diversiseta sp. nov., male terminalia (holotype, MECN-EN-DIP-4860). A, C, ventral view; B, posterior view; D, dorsal view; E, ventral branch gonostylus, dorsal view. Scale bar = 0.1 mm.Abbreviations:gc pvmo = medial outgrowth of posteroventral margin of gonocoxites, gst db = dorsal branch of gonostylus, gst vb = ventral branch of gonostylus.

FIGURE 6. Zygomyia flamma sp. nov., male terminalia (holotype, MECN-EN-DIP-4861). A, B, ventral view; C, dorsal view; D, posterior view; E, gonostylus, dorsal view. Scale bar = 0.05 mm (A–D) and 0.02 mm (E). Abbreviations: gst dbal = anterior lobe of dorsal branch of gonostylus, gst dbpl = posterior lobe of dorsal branch of gonostylus, gst dbf = flame-shaped megaseta on dorsal branch of gonostylus, gst vbdl = dorsal lobe of ventral branch of gonostylus, gst vbmf = flame-shaped megasetae on ventral branch of gonostylus, gst vbvl = ventral lobe of ventral branch of gonostylus.

FIGURE 9. Zygomyia napoensis sp. nov., male terminalia (holotype, MECN-EN-DIP-4864). A, B, ventral view; C, dorsal view; D, posterior view; E, gonostylus, dorsal view. Scale bar = 0.1 mm (A–D) and 0.02 mm (E).

FIGURE 10. Zygomyia paniculata sp. nov., male terminalia (holotype, MECN-EN-DIP-4865). A, B, ventral view; C, dorsal view; D, posterior view. Scale bar 0.1 mm (A, C) and 0.05 mm (B, D).

FIGURE 11. Zygomyia pectinella sp. nov., male terminalia (holotype, MECN-EN-DIP-4866). A, B, ventral view; C, postero-dorsal view; D, posterior view; E, dorsal view; F, gonostylus, dorsal view. Scale bar = 0.1 mm (A–C, E), 0.05 mm (D) and 0.02 mm (F). Abbreviations: gst db = dorsal branch of gonostylus, gst vbdl = dorsal lobe of ventral branch of gonostylus, gst vbvl = ventral lobe of ventral branch of gonostylus.

FIGURE 12. Zygomyia spinosa sp. nov., male terminalia (holotype, MECN-EN-DIP-4867). 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 13. Zygomyia talpaeforma sp. nov., male terminalia (holotype, MECN-EN-DIP-4868). A, ventral view; B, dorsal view; C, D, lateral view; E, gonostylus, dorsal view. Scale bar = 0.1 mm (A–D), 0.05 mm (E).

FIGURE 14. Zygomyia trilobata sp. nov., male terminalia (holotype, MECN-EN-DIP-4869). A, B, ventral view; C, posterior view; D, dorsal view; E, gonostylus, dorsal view. Scale bar = 0.1 mm (A–D) and 0.02 mm (E).

FIGURE 15. Zygomyia triseta sp. nov., male terminalia (holotype, MECN-EN-DIP-4870). A, B, ventral view; C, dorsal view; D, posterior view. Scale bar = 0.1 mm.

FIGURE 16. Zygomyia uniordata sp. nov., male terminalia (holotype, MECN-EN-DIP-4871). A, B, ventral view; C, dorsal view; D, posterior view; E, gonostylus, dorsal view. Scale bar = 0.05 mm (A–D) and 0.02 mm (E).

FIGURE 17. Zygomyia ximoi sp. nov., male terminalia (holotype, MECN-EN-DIP-4872). A, B, ventral view; C, dorsal view; D, posterior view; E, gonostylus, dorsal view. Scale bar = 0.05 mm (A–D) and 0.02 mm (E).

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).