Leptomorphus species

Borkent, Christopher J. & Wheeler, Terry A., 2012, Systematics and Phylogeny of Leptomorphus Curtis (Diptera: Mycetophilidae) 3549, Zootaxa 3549, pp. 1-117 : 11-13

Key to adults of Leptomorphus species

For confirmation of species identification the genitalia of male specimens should be compared to figures. Future additions or revisions to this key (of taxa, characters or images) can be found at http://sciaroidea.info/ Leptomorphus _Key.

This key does not include eight new species recently described from the Oriental and northern Australasian region by Papp & Ševčík (2011) (see ‘Specimens and species not included’ section below and Figs. 138–139 for distributions). These species should run to L. tagbanua with the exception of L. alienus , which would run to L. tabatius . Papp & Ševčík (2011) provide a key to these eight species.

1. Vein R 4 present (i.e. Figs. 64, 65)......................................................................... 2

- Vein R 4 absent (i.e. Fig. 57)............................................................................. 8

2. (1) Lateral ocelli no more than their own diameter away from eye margin ( Fig. 79); foretarsomere slightly shorter than foretibia; male unknown ( USA: California, Fig. 148)................................... L. perplexus Borkent , n. sp.

- Lateral ocelli more than their own diameter away from eye margin, grouped closely with median ocellus at vertex ( Fig. 78); foretarsomere I longer than foretibia...................................................................... 3

3. (2) Vein R 4 joining Rs or junction of Rs and r-m, forming a triangular cell ( Fig. 65); genitalia as in Fig. 112 (southeastern South America, Fig. 142)..................................................................... L. neivai Edwards.

- Vein R 4 joining Rs beyond junction of Rs and r-m, forming a quadrilateral cell (i.e. Figs. 60, 64) (Nearctic, Palaearctic).... 4

4. (3) Apex of antennae (at least apical 5 flagellomeres) white, base black or dark brown (e.g. Figs. 24–27, 31)............. 5

- Antennal flagellomeres (except, rarely, base of first flagellomere) uniformly coloured (e.g. Figs. 1–7).................. 6

5. (4) Male with large apical spine-like process on midfemur ( Fig. 83); male genitalia with two long sickle-like structures curving dorsally ( Fig. 111); colour varying from completely black to mostly yellow with dark brown markings on thorax and abdomen ( Figs. 24–27) ( Canada, northern and eastern USA, Fig. 144)................................. L. nebulosus (Walker) .

- Male without large apical spine-like process on midfemur; male genitalia as in Fig. 114 without long sickle-like structures; body completely black/ dark brown ( Fig. 31) ( Japan and far eastern Russia, Fig. 141)...... L. panorpiformis (Matsumura) .

6. (4) Male genitalia with two long sickle-like structures curving dorsally ( Figs. 108, 117); scutum with setae on entire surface; colour either yellow with brown head, or dark brown/ black (females with tergite 4 red-orange) with yellow coxae and femora ( Figs. 21, 36–37)...................................................................................... 7

- Male genitalia without sickle-like structures ( Fig. 94); scutum with setae restricted to dorsocentral line and margins; thorax varying from dark to light brown, when light brown scutum with two posteriorly converging dark lines; abdomen varying from light to reddish brown, tergites 1–2 often dark brown ( Figs. 4–5) (southern Canada, south in eastern USA to NC, Fig. 147)....................................................................................... L. bifasciatus (Say) .

7. (6) Completely yellow with brown head ( Fig. 21) (eastern North America, Fig. 145)........... L. magnificus (Johannsen) .

- Thorax and abdomen completely dark brown/black in male, female identical except with tergite 4 reddish-brown; coxae and femora yellow ( Fig. 36–37) (central and eastern North America, Fig. 146)................. L. subcaeruleus (Coquillett) .

8. (1) Scutum evenly covered with trichia ( Fig. 80) or fine setae; male foretibia with 1–2 dense rows (combs) of short anteroventral bristles (spacing between bristles usually less than bristle length) ( Figs. 85, 89–90).............................. 9

- Scutal setae or trichia (if present) restricted to dorsocentral and lateral rows ( Fig. 81); male foretibia without dense row of anteroventral bristles ( Figs. 87–88)...................................................................... 22

9. (8) Scutellum with covering of yellow or white fine trichia and without bristles; Neotropical or Afrotropical............ 10

- Scutellum without covering of fine trichia, but with brown, small or large, bristles (i.e. with sockets); Nearctic or Palaearctic. ................................................................................................... 17

10. (9) Palp segment 5 with thick covering of fine, white setulae and with or without a few setae ( Fig. 82); vein sc-r present (i.e. Fig. 57); Neotropical.................................................................................. 11

- Palp segment 5 without covering of fine, white setulae, but with a few dark setae; vein sc-r absent ( Fig. 58); genitalia as in Fig. 105 (eastern Madagascar, Fig. 134)........................................................ L. grjebinei Matile.

11. (10) Scutellum dark brown (rarely yellow), same colour as scutum and mediotergite............................... 12

- Scutellum light brown, yellow or white, distinctly paler than scutum and mediotergite.............................. 15

12. (11) Fore- and midfemora and tibia yellow ( Figs. 3, 14)...................................................... 13

- Fore- and midfemora with brown or dark brown spots basally extending from 1/3 to ¾ towards apex, fore- and midtibia with apical ½ or entirely brown or dark brown ( Figs. 6, 15)....................................................... 14

13. (12) At least abdominal segments 2–4 mostly yellow ( Fig. 14); metepisternum yellow or white; male genitalia with gonocoxite arising at base of tergite 9 and almost as long as tergite 9, gonocoxite with long thin process, as long as gonocoxite, arising mediobasally and armed with 4 long apical bristles pointed laterally ( Fig. 101) ( Panama, northern South America and Amazonia, Fig. 142)................................................................ L. fasciculatus Edwards.

- Abdominal segments 2–4 with some brown or dark brown ( Fig. 3); metepisternum completely or partially brown; male genitalia with gonocoxite arising ¼ of length of tergite 9 towards apex, gonocoxite with scalloped edge apicomedially and hook-like process laterally ( Fig. 92) (southern Brazil, Fig. 142)..................................... L. amorimi Borkent , n. sp.

14. (12) Metepisternum brown; male genitalia yellow or white; tergite 9 rounded basally, tapering to a single, long, point posteriorly that extends beyond cerci ( Fig. 95) ( Costa Rica, Fig. 143)............................. L. brandiae Borkent , n. sp.

- Metepisternum yellow or yellow with brown dorsally; male genitalia partially brown; apex of tergite 9 not extending past cerci; tergite 9 posteriorly with some scalloping on apicolateral corner and with 3 rounded medial processes, with central shorter than laterals ( Fig. 102) ( Peru and Bolivia, Fig. 143)................................... L. femoratus Edwards.

15. (11) Abdomen mostly yellow, brown posteriorly (posterior half of tergite 5 and all of T6–7, Fig. 39); medial wing spot (macula) only around junction of R and M 1+2, not reaching anterior or posterior wing margin as a complete band ( Fig. 77); halter yellow; antennal flagellomere 6 almost square (slightly longer than wide); male genitalia with tergite 9 tapering posteriorly to a point, with short pointed processes laterally at 2/3 of length towards apex; gonocoxite with long projection on medial margin ( Fig. 124); female unknown ( Ecuador, Fig. 143)......................................... L. waodani Borkent , n. sp.

- Abdomen striped brown and yellow ( Figs. 10, 12); medial wing spot (macula) strong and running from anterior to posterior wing margin as a complete band, though fainter posteriorly ( Figs. 50, 52); halter with base of stem yellow, remainder brown; antennal flagellomere 6 1.5–2X longer than wide; male genitalia not as above.................................... 16

16. (15) Male genitalia with tergite 9 tridentate posteriorly (medial process laterally compressed); gonocoxite placed posteriorly on tergite 9, gonostylus small (~1/4 length of gonocoxite) with two short, round, apical projections ( Fig. 100) ( Costa Rica, Fig. 143)........................................................................... L. eberhardi Borkent , n. sp.

- Male genitalia with tergite 9 posterior margin rounded laterally and concave medially, lateral process apex with 5 rows of tightly spaced short blunt brown bristles; gonocoxite placed basally on, and subequal in length to, tergite 9; gonostylus ~2/3 length of gonocoxite with two apical processes, medial one most pronounced and tapering to a point, the lateral ½ the length of medial, thin and rod-like ( Fig. 98); female unknown (northern Argentina (Tucumán province), Fig. 142).............................................................................................. L. crassipilus Borkent , n. sp.

17. (9) Abdomen brown or dark brown ( Fig. 33)............................................................... 18

- Abdomen mostly yellow, tergite 7 and often posterior margin of other tergites brown ( Figs. 16–17, 41)................. 19

18. (17). Scutum and mediotergite dark brown; gonocoxite with lateral process of uniform thickness on apical 2/3 ( Fig. 116) (far eastern Palaearctic, Fig. 141).................................................. L. quadrimaculatus (Matsumura) .

- Scutum with posterolateral corners yellow; mediotergite yellow with central brown spot; gonocoxite with lateral process swollen at apex ( Fig. 118) (north-western Russia and Finland, Fig. 140)................... L. subforcipatus Zaitzev & Ševčík.

19. (17) Wing with apical spot very pale and restricted to apical ¼ of cell r1; medial spot absent ( Fig. 56); male genitalia with sternite 9 bearing a medial invagination for posterior 2/3 and with 2 dark, apical points ( Fig. 104) (New Mexico, Arizona and Northern Mexico, Fig. 148).......................................................... L. furcatus Borkent , n. sp.

- Wing with dark apical and medial spots present ( Figs. 55, 76); male genitalia with sternite 9 two dimensional (no ventral points or invaginations, Figs. 103, 123)......................................................................... 20

20. (19) Halter yellow; male genitalia with gonocoxite shorter than tergite 9; sternite 9 not reaching lateral margins of tergite 9 ( Fig. 123) (Europe, Fig. 140)............................................................... L. walkeri Curtis.

- Halter with stem yellow and knob brown; male genitalia with gonocoxite at least 1.5X length of tergite 9; sternite 9 wider than long, reaching lateral margins of tergite 9 ( Figs. 103, 121).................................................... 21

21. (20) Gonocoxite straight for ¾ of length and then angularly bent medially and swollen beyond bend ( Fig. 121) ( Azerbaijan, Fig. 140)................................................................... L. talyshensis Zaitzev & Ševčík.

- Gonocoxite smoothly curved along entire length, not swollen at apex ( Fig. 103) (Europe, Fig. 140)... L. forcipatus Landrock.

22. (8) Laterotergite and anepisternum brown; anepimeron at least partially brown ( Figs. 7, 40); Oriental or Palaearctic....... 23

- Laterotergite, anepisternum and anepimeron yellow (i.e. Figs. 8, 20); Afrotropical or Nearctic........................ 28

23. (22) Katepisternum brown; metepisternum at least partially brown or light brown; wing without apical spot ( Figs. 48, 73, 74); segments 3–5 of abdomen noticeably swollen relative to other segments ( Figs. 35, 40).............................. 24

- Katepisternum and metepisternum yellow; wing with pale brown apical wing spot reaching to wing tip ( Figs. 44, 67, 75); abdominal segments all relatively the same thickness ( Figs. 2, 30, 38)........................................... 26

24. (23) Scutum dark brown............................................................................... 25

- Scutum dark brown with small yellow spots on posterolateral corners; genitalia with tergite 9 bearing two long lateral processes posteriorly, so that tergite 9 is ~2X as long as wide ( Fig. 120); female unknown (Sulawesi, Fig. 137)............................................................................................... L. tabatius Borkent , n. sp.

25. (24) Metepisternum brown; antennal flagellomere 1 with base yellow, remainder brown; vein sc-r joining R within its own length of origin of Rs; known only from female holotype ( Fig. 7) ( northern Borneo , Fig. 137).......... L. chaseni Edwards

- Metepisternum brown anteriorly, yellow posteriorly; antennal flagellomere 1 yellow; vein sc-r joining R at ~2X its own length from origin of Rs; genitalia wider than long ( Fig. 119); female unknown ( Philippines, Fig. 137).. L. tagbanua Borkent , n. sp.

26. (23) Scutellum yellow; pale medial wing spot absent ( Figs. 67, 75); genitalia with gonostylus bearing two apical projections ( Fig. 122)........................................................................................... 27

- Scutellum dark brown; pale medial wing spot present ( Fig. 44); genitalia with gonostylus a single blunt taper ( Fig. 93); female unknown ( Japan, Fig. 141)............................................................... L. babai Sasakawa.

27. (26) Vein sc-r present (though faint in one specimen); genitalia as in Fig. 122 ( Peninsular Malaysia, Fig. 137)........................................................................................ L. titiwangsensis Borkent , n. sp .

- Vein sc-r absent or present; genitalia presumably different from above (male unknown) (eastern India and Nepal, Fig. 137)........................................................................................ L. ornatus Brunetti.

28. (22) Scutellum brown or dark brown..................................................................... 29

- Scutellum yellow..................................................................................... 32

29. (28) Halter with most of stem and knob dark brown; gonostylus with two large lobes ( Figs. 99, 106, 113), Afrotropical; females not currently distinguishable beyond this point ............................................................. 30

- Halter mostly yellow with only tip of knob brown; gonostylus with single large, hook-tipped lobe ( Fig. 107) Nearctic ( Fig. 149)............................................................................... L. hyalinus Coquillett.

30. (29) Genitalia with tergite 9 gradually tapering on apical quarter, apex bearing medial spur and often a secondary small bump or point, also with strong, ventrally-produced, thin ridge running across ventral surface at approximately 2/3 the distance towards apex, creating a semicircular dorsal margin when viewed caudally ( Fig. 113) (central-western Africa, Fig. 136).......................................................................................... L. obscurus Matile.

- Genitalia with tergite 9 ending in more or less blunt apex laterally and with or without small spine-like projection on medial corner (e.g. Figs. 99, 106).............................................................................. 31

31. (30) Genitalia with posterolateral projection of tergite 9 either square or with slightly acute angle on medial corner; gonostylus with shortest lobe rounded ( Fig. 106); female unknown ( Gabon and Central African Republic, Fig. 135)... L. gracilis Matile.

- Genitalia with posterolateral projection of tergite 9 bearing distinct thin point on medial corner; gonostylus with shortest lobe gradually tapering to thick point ( Fig. 99) (central western Africa, Fig. 136)........................ L. crosskeyi Matile.

32. (28) Abdomen mostly yellow with at most brown bands posteriorly on tergites 3–6, tergite 7 brown or yellow ( Figs. 22, 23, 34) ................................................................................................... 33

- Abdomen yellow with varying amounts of brown on tergites 3–5, tergite 6 brown, tergite 7 yellow ( Figs. 1, 8, 9), females not currently distinguishable beyond this point ................................................................ 35

33. (32) Scutum mostly yellow with prealar brown spots (sometimes united as a band) or brown Y-shaped medial marking; abdomen with tergite 7 yellow ( Figs. 22, 34)................................................................... 34

- Scutum mostly dark brown with yellow restricted to anterior and lateral margins; abdomen with tergite 7 brown ( Fig. 23); genitalia with tergite 9 bearing ventrally-directed fold along most of posterior margin and small point on apicomedial corner ( Fig. 109); female unknown ( South Africa, Fig. 134)......................................... L. mandelai Borkent , n. sp.

34. (33) Scutum with brown Y-shaped medial marking and prealar brown spots ( Fig. 81); genitalia with tergite 9 ending in square lobe bearing small medial point; sternite 9 more or less oval shaped ( Fig. 115) ( Tanzania, Fig. 134).................................................................................................... L. stigmatus Borkent , n. sp.

- Scutum with prealar brown spots or band only ( Fig. 22); genitalia with lateral lobes of tergal evagination gradually tapering to a medial point; sternite 9 a posteriorly directed triangle ( Fig. 110) ( Guinea and Nigeria, Fig. 136)........ L. medleri Matile.

35. (32) Tergite 9 with basal 2/3 of lateral margins parallel; ventrally directed process at base of posterior lobe of tergite 9 forked into two points at apex; apex of posterior lobe blunt and slightly bulbous ( Fig. 91) (central and western Africa, Fig. 135)........................................................................................... L. aliciae Matile.

- Tergite 9 with basal 2/3 of lateral margins bulbous tapering posteriorly; ventrally directed process at base of posterior lobe of tergite 9 a single point. ( Figs. 96, 97)..................................................................... 36

36. (35) Concavity of posterior margin of tergite 9 longer in diameter than width of sternite 9; posterior lobes of tergite 9 tapering to blunt points ( Fig. 97) ( Ivory Coast and Ghana, Fig. 135)...................................... L. couturieri Matile.

- Concavity of posterior margin of tergite 9 smaller in diameter than width of sternite 9; posterior lobes of tergite 9 tapering first to create a lateral corner and then tapering to a point on medial margin ( Fig. 96) ( Republic of the Congo and Democratic Republic of the Congo, Fig. 135)......................................................... L. carnevalei Matile.