Stenochironomus Kieffer

Dantas, Galileu P. S., Hamada, Neusa & Mendes, Humberto F., 2016, Contribution to the knowledge of Stenochironomus Kieffer (Diptera, Chironomidae) from Brazil: seven new species and description of females and immatures of some previously known species, Zootaxa 4117 (1), pp. 1-47 : 45-46

Key to males of Neotropical Stenochironomus Kieffer

(modified from Borkent, 1984, S. licinus Borkent was not included)

1. Thorax, wing, legs, and abdominal tergites without dark markings or, at most, wing membrane uniformly light brown and apex of fore femur and all of fore tibia and tarsus darkened........................................................ 2

1’. Thorax, wings, legs or abdominal tergites (or several of these) with distinct darker markings......................... 8

2. Anal point broad at base and with dorsal crest extending laterally along length..................................... 3

2’. Anal point narrow at base, either with expanded apex or narrow posteriorly but not with dorsal crest................... 4

3. Thorax anteriorly elongated; setal patch of T IX on posteriorly projecting lobe...................... S. prolatus Borkent

3’. Thorax not anteriorly elongated; setal patch of T IX arranged on flattened area........................ S. vatius Borkent

4. Anal point strongly spatulated........................................... S. atlanticus Pinho, Mendes et Marcondes

4’. Anal point tapering or parallel-sided....................................................................... 5

5. T IX with strong setae on a posterolateral flap................................ S. sebastiao Andersen, Mendes et Pinho

5’. T IX without strong setae on a posterolateral flap............................................................ 6

6. Apex of T IX wedge-shaped in dorsal view; apical seta on appendage 2 elongated, about as long as subapical seta....... 7

6’. Apex of T IX truncated in dorsal view; apical seta on appendage 2 stout, shorter than subapical seta........ S. reissi Borkent

7. Phallapodeme curved anterioly....................................................... S. palliaculeatus Borkent

7’. Phallapodeme not curved anterioly.......................................... S. maikeae Andersen, Mendes et Pinho

8. Posterior margin of TIX with lateral lobes.................................................................. 9

8’. Posterior margin of TIX without lateral lobes............................................................... 10

9. TIX with wedge-shaped apex, with short lateral lobes................... S. messias Reis, Serpa-Filho et Ferreira-Keppler

9. TIX with square-shaped apex, with large protruding lateral lobes.......... S. oliveirai Reis, Serpa-Filho et Ferreira-Keppler

10. Fore femur with three discrete areas of pigmentation; only lateral and posterior margins of T II–IV pigmented.............................................................................................. S. triannulatus Borkent

10’. Fore femur with, at most, two areas of pigmentation; abdomen variably pigmented but not as above................... 11

11. Anal point broad at base and with dorsal crest extending laterally along length.................................... 12

11’. Anal point narrow at base, either with or without expanded apex but not with dorsal crest........................... 21

12. Lateral vitta completely pigmented; halter dark brown; eye not metallic.......................................... 13

12’. Lateral vitta, at most, only partially pigmented; halter pale; eye not metallic or shiny metallic........................ 14

13. Entire scutum dark brown; AR>100..................................................... S. crusanticus Borkent

13’. Only portion of scutum dark brown; AR<100................................................ S. innocus Williams

14. Superior volsella extending beyond apex of gonocoxite..................................................... 15

14’. Superior volsella, at most, to level of apex of gonocoxite.................................................... 17

15. Apex of anal point bulbosus............................................................. S. bacrionis Borkent

15’. Apex of anal point tapering............................................................................ 16

16. Anal point relatively broad; superior volsella with 10–14 setae................................. S. pectinatus Borkent

16’. Anal point relatively slender; superior volsella with 4–9 setae.................................... S. gladius Borkent

17. Mid and hind legs with pigmentation; thorax with pigmentation................................................ 18

17’. Mid and hind legs pale; thorax without pigmentation........................................ S. albidorsalis Borkent

18. Superior volsella with pointed apex...................................................... S. manauara sp. nov.

18’. Superior volsella with blunted apex..................................................................... 19

19. Lateral vitta and postnotum without pigmentation.............................................. S. gracilis sp. nov.

19’. Lateral vitta and postnotum with pigmentation.............................................................. 20

20. Gonostylus swollen subapically, apex tapering................................................ S. fittkaui Borkent

20’. Gonostylus slender with uniform width along its length ( Fig. 7 ).................................... S. bare sp. nov.

21. Lateral vitta connected medially with dark pigmentation..................................................... 22

21’. Lateral vitta with or without pigmentation but not connected medially with darker pigmentation...................... 23

22. Lateral vitta with two areas of dark pigmentation; nearly entire postnotum pigmented; posterior portion of abdominal T IV pig- mented......................................................................... S. semifumosus (Edwards)

22’. Lateral vitta with only anterior portion pigmented; dorsal portion of postnotum pigmented; abdominal T IV pale............................................................................................... S. zonarius Borkent

23. Lateral vitta with two dark patches, one situated anteriorly to the other......................................... 24

23’. Lateral vitta with one dark patch or pigmentation absent...................................................... 25

24. Fore femur and tibia with dorsal and ventral rows of setae more elongated than those of mid and hind legs; apex of anal point expanded in dorsal view; AR = 2.03–2.15.................................................... S. jubatus Borkent

24’. Fore femur and tibia with setae of similar length to those of mid and hind legs; apex of anal point slightly bulbosus in dorsal view; AR = 1.15–1.80.............................................................. S. quadrinotatus Borkent

25. Nearly entire thorax completely brown; abdomen pale........................................... S. varius Borkent

25’. Thorax mostly pale, with or without pattern of markings; abdomen pale or with pattern of marking.................. 26

26. Lateral vitta with pigmentation along lateral margin which extends to anterior point of scutum........ S. leptopus (Kieffer)

26’. Lateral vitta with or without dark pigmentation; scutum with dark or light pigmentation, or without pigmentation, but never with pigmentation extending anterior of lateral vitta........................................................ 27

27. 2/3 anterior of scutum ( Fig. 1 B) and abdomen with dark pigmentation.......................... S. amazonicus sp. nov.

27’. Anterior margin of scutum with or without pigmentation, but never dark pigmented; abdomen with or without pigmentation................................................................................................... 28

28. Lateral vitta with one dark patch along anterior margin; mid and hind legs pale.................................... 29

28’. Lateral vitta with pigmentation restricted to stripe along lateral margin or lacking dark pigmentation; mid and hide legs with or without pigmentation................................................................................. 32

29. Anal point expanded at apex................................................ S. roquei Dantas, Hamada at Mendes

29’. Anal point not expanded at apex........................................................................ 30

30. Gonostylus stout (fig. 25); thirteenth flagellomere> 1.5 mm ..................................... S. suzanae sp. nov.

30’. Gonostylus not stout; thirteenth flagellomere <1.5 mm ....................................................... 31

31. Abdomen with dark pigmentation; posterior setae of setal patch on T IX on posteriorly projecting lobe..................................................................................................... S. impendens Borkent

31’. Abdomen lacking dark pigmentation; setal patch on T lX arranged on flattened area................ S. aculeatus Borkent

32. Lateral vitta with dark stripe along lateral margin; T IX markedly broad............................. S. discus Borkent

32’. Lateral vitta with pigmentation not as above or lacking dark pigmentation; T IX not broad.......................... 33

33. Lateral vitta with a dark brown patch somewhat elliptic on posterior margin ( Fig. 8 B).......... S. figueiredoensis sp. nov.

33’. Lateral vitta with a dark pigmentation not as above or lacking dark pigmentation.................................. 34

34. Lateral vitta with dark pigmentation ( Fig. 15 B)................................................. S. liviae sp. nov.

34’. Lateral vitta lacking dark pigmentation................................................................... 35

35. T I with dark pigmentation................................................................ S. townes Borkent

35’. T I lacking dark pigmentation............................................................ S. nudipupa Borkent

Figures

FIGURE 1. Stenochironomus amazonicus sp. nov., adult male. A, head. B, thorax. C, hypopygium. D, wing. Pupa: E, tergite II. Larva: F, head in ventral view. Egg: G, egg in lateral view.

FIGURE 7. Stenochironomus bare sp. nov., adult male. A, hypopygium in dorsal view. B, hypopygium with tergite IX removed, left dorsal view, right ventral view.

FIGURE 8. Stenochironomus bare sp. nov., pupae. A, frontal apotome. B, anterior part of thorax, in lateral view. C, tergites I – IV. D, tergites V – IX. E, spur on S VIII. F, apex of anal lobes.

FIGURE 15. Stenochironomus impendens Borkent, adult female. A, genitalia, dorsal view. B, genitalia, ventral view.