Baccha

Mengual, Ximo, Miranda, Gil Felipe G. & Thompson, F. Christian, 2018, Unraveling Ocyptamus and the Baccha legacy (Diptera: Syrphidae): redefinition of groups and new species descriptions, Zootaxa 4461 (1), pp. 1-44: 4-7

publication ID

https://doi.org/10.11646/zootaxa.4461.1.1

publication LSID

lsid:zoobank.org:pub:C0F0C0EF-D22C-47ED-9400-F50A8E122DD0

persistent identifier

http://treatment.plazi.org/id/4C610E46-E46A-FF83-FF0F-FA2F08A5B75A

treatment provided by

Plazi

scientific name

Baccha
status

 

Key to the New World groups of “ Baccha  ” of authors

The identification key includes all the taxonomic groups from the New World that have been considered at some point as part of Baccha  sensu lato by previous authors, or groups that comprise or have comprised species originally described as Baccha  species, mostly due to the elongate and/or petiolate abdomen. The key is helpful to identify all the different genera and the significant species groups within them. Two species are keyed out due to their unique combination of morphological features: i.e., Ocyptamus pola ( Curran, 1939)  and Ocyptamus maximus Thompson  sp. nov., and a third species is keyed out because its genus is monotypic, Atylobaccha flukiella ( Curran, 1941)  . Moreover, species left as incertae sedis appear in the identification key without any assigned genus name, i.e., grata Curran  , conjunctus Wiedemann  , sargoides Macquart  , and placiva Williston. The  only exception to this procedure with incertae sedis species is Ocyptamus maximus Thompson  sp. nov., here placed under Ocyptamus  but we acknowledge that its generic affinities are uncertain. Please refer to the below section ‘Nomenclatural acts arranged alphabetically by valid name’ for more information about these species.

1 Metafemur without spinose setae ( Fig. 1View FIGURES 1–10. 1). Postmetacoxal bridge incomplete ( Fig. 11View FIGURES 11–19. 11) or complete ( Figs 3, 4View FIGURES 1–10. 1). Vein M1 at most slightly sinuate; vein R4+5 straight; rarely both veins strongly sinuate, but then without spinose setae on metafemur........ 3

- Metafemur with distinct anteroventral and posteroventral rows of spinose setae on apical 1/2 ( Fig. 2View FIGURES 1–10. 1). Metepimera continuous behind metacoxae and forming a complete postmetacoxal bridge ( Figs 3, 4View FIGURES 1–10. 1). Vein M1 very abruptly and strongly sinuate; vein R4+5 slightly to strongly sinuate ( Figs 5, 6View FIGURES 1–10. 1).................................................................. 2

2 Vein R4+5 strongly sinuate ( Fig. 5View FIGURES 1–10. 1). Abdominal tergum 1 produced laterally into a strong spur ( Figs 3, 9View FIGURES 1–10. 1). Postmetacoxal bridge complete, wide ( Fig. 3View FIGURES 1–10. 1). Dorsal occiput pile reduced to a single row............................ Salpingogaster Schiner 

- Vein R4+5 only slightly sinuate ( Fig. 6View FIGURES 1–10. 1). Abdominal tergum 1 with a small spur ( Fig. 10View FIGURES 1–10. 1). Postmetacoxal bridge complete with a less sclerotized medial line (semi-membranous) ( Fig. 4View FIGURES 1–10. 1). Dorsal occipital pile in 3–4 rows........... Eosalpingogaster Hull 

3 Anterior anepisternum usually with some distinct short pile posterodorsally ( Figs 7, 8View FIGURES 1–10. 1); metaepisternum usually with some long erect or subappressed pile ventrad to spiracle ( Fig. 11View FIGURES 11–19. 11); always with pile on one of these two areas................. 5

- Anterior anepisternum ( Fig. 12View FIGURES 11–19. 11) and metaepisternum bare...................................................... 4

4 Oral margin at the same level of facial tubercle, in lateral view ( Fig. 12View FIGURES 11–19. 11); facial tubercle always present and in line with oral margin. Thorax without yellow markings except on scutellum..................................... Dioprosopa Hull 

- Oral margin anterior to facial tubercle, in lateral view ( Fig. 13View FIGURES 11–19. 11); if facial tubercle is missing, then face always pointed forward and oral margin beyond the medial point between oral margin and antennal bases ( Fig. 14View FIGURES 11–19. 11). Postpronotum yellow; notopleuron usually yellow; pleuron more extensively yellow ( Fig. 13View FIGURES 11–19. 11)....................................... Rhinoprosopa Hull 

5 Male genitalia: phallus (aedeagus) simple, unsegmented. Face usually straight, oral margin and antennal bases in line, without tubercle ( Figs 15, 18View FIGURES 11–19. 11). Abdomen petiolate; abdominal tergum 2 narrow, narrower than terga 3 and 4 ( Fig. 18View FIGURES 11–19. 11). Female: abdominal segment 6 not noticeable nor visible without dissection, internal to segment 5.................... Leucopodella Hull  [Note: Two undescribed species of Leucopodella  have tuberculate face.]

- Male genitalia: phallus segmented into basiphallus and distiphallus ( Figs 58–60View FIGURES 55–61. 55, 111View FIGURES 106–111. 106). Face usually with a facial tubercle ( Figs 16View FIGURES 11–19. 11, 32View FIGURES 32–37. 32–35), at least slightly convex ( Figs 17View FIGURES 11–19. 11). Abdomen variable. Female: abdominal segment 6 conspicuous, easily visible.... 6

6 Face gently convex; facial tubercle weak ( Fig. 17View FIGURES 11–19. 11); metaepisternum bare; abdomen petiolate ( Fig. 19View FIGURES 11–19. 11)............................................................................................... Atylobaccha flukiella (Curran) 

- Face with distinct medial tubercle and/or more convex; metaepisternum bare or pilose; abdomen variable................ 7

7 Eye with a distinct triangular emargination on posterior margin ( Fig. 20View FIGURES 20–31. 20). Ocellar triangle distanced from eye contiguity on male ( Fig. 21View FIGURES 20–31. 20). Face convex or produced anteriorly ( Figs 20, 22View FIGURES 20–31. 20). Abdomen usually oval or parallel-sided, never strongly petiolate or very long and narrow; abdominal markings usually constituted of apical dark fascia with a medial pair of dark vittae directed towards base in a yellow background ( Fig. 23View FIGURES 20–31. 20) or a pattern derived from that ( Fig. 24View FIGURES 20–31. 20), including entirely dark terga (Mengual 2011). Male genitalia with sclerotized, very short to long, triangular process arising from fused surstylar apodemes and projecting apically between bases of surstyli ( Figs 25, 26View FIGURES 20–31. 20).................................. Toxomerus Macquart 

- Posterior margin of eye with emargination usually indistinct or shallow and rounded ( Figs 27View FIGURES 20–31. 20, 32View FIGURES 32–37. 32–35). Ocellar triangle touching eye contiguity on male ( Figs 28View FIGURES 20–31. 20, 57View FIGURES 55–61. 55, 79View FIGURES 78–84. 78). Face never produced anteriorly. Abdomen variable; abdominal markings never derived from medial pair of stripes as above ( Figs 29, 30View FIGURES 20–31. 20). Male genitalia without such single acute sclerotized process, at most with a bilobate process ( Fig. 31View FIGURES 20–31. 20).......................................................................... 8

8. Very large dark flies, larger than 20 mm. Abdomen petiolate, mostly dark; abdominal tergum 2 with two hyaline maculae basolaterally; sternum 2 translucent on basal 2/3 ( Figs 32, 33, 35, 37View FIGURES 32–37. 32–35)... Ocyptamus maximus Thompson  sp. nov. [incertae sedis]

- Flies never so large, less than 20 mm. Abdomen variable; if tergum 2 with hyaline maculae basolaterally, then fly pale and abdomen not petiolate ( Fig. 38View FIGURES 38–45. 38).......................................................................... 9

9. Basoflagellomere deeply incised, forming dorsal and ventral lobes ( Fig. 40View FIGURES 38–45. 38). Male tergum 4 concave apically, so apical abdominal segments can be flexed dorsally; male sternum 4 produced greatly ventrally ( Figs 40, 41, 42View FIGURES 38–45. 38). Female abdominal segment 5 slightly asymmetric; female spermatheca large but abruptly narrowed on the end connected to the spermathecal duct, paddleshaped, covered in spine-like protuberances ( Fig. 43View FIGURES 38–45. 38)................................... grata Curran  [incertae sedis]

- Basoflagellomere oval to elongate ( Figs 27View FIGURES 20–31. 20, 45View FIGURES 38–45. 38). Male abdomen not so modified. Female abdominal segment 5 symmetric; female spermatheca not so modified...................................................................... 10

10. Antennal segments of similar length, subequal; antenna elongate ( Fig. 27View FIGURES 20–31. 20). Abdominal terga 3 and 4 with a subbasal yellow fascia and a pair of oblique, pale vittae ( Fig. 44View FIGURES 38–45. 38).............................. conjunctus Wiedemann  [incertae sedis]

- Scape and pedicel each much shorter than basoflagellomere; antenna not elongate ( Figs 47, 54View FIGURES 46–54. 46). Abdominal terga differently marked (except for placiva  )............................................................................ 11

11. Abdomen parallel-sided, elongate, mainly orange and without a distinct pattern of markings ( Fig. 38View FIGURES 38–45. 38); tergum 2 with basolateral hyaline areas. Metafemur pale with long, thick, mostly orange pile on dorsal and ventral surface ( Fig. 39View FIGURES 38–45. 38), with a few long black pile basoventrally..................................................... sargoides Macquart  [incertae sedis]

- Abdomen variable; abdominal segment 2 without hyaline areas. If metafemur pale with long, thick pile, then pile black ( Fig. 103View FIGURES 99–105. 99) and abdominal terga with four pale vittae............................................................. 12

12. Wing almost completely bare, microtrichose on apical 1/4 ( Fig. 46View FIGURES 46–54. 46)........................... Pseudoscaeva Vockeroth 

- Wing extensively microtrichose......................................................................... 13

13. Pedicel with narrow projection over basoflagellomere ( Fig. 45View FIGURES 38–45. 38); basoflagellomere sub-triangular, usually large on female. Scutum with a distinct anterior row of longer pile, i.e. mesonotal collar ( Fig. 49View FIGURES 46–54. 46). Abdomen parallel-sided to slightly oval............................................................................. Ocyptamus Macquart  sensu stricto

- Apical margin of pedicel straight, rounded, without an extension over basoflagellomere ( Fig. 51View FIGURES 46–54. 46); basoflagellomere oval to round. Scutum usually without an anterior row of longer pile. Abdomen variable................................. 14

14. Eye sometimes pilose ( Figs 52, 54View FIGURES 46–54. 46). Abdomen spatulate, never Syrphus  -like ( Fig. 53View FIGURES 46–54. 46). Wing mostly dark with hyaline areas on basomedial cells ( Figs 52, 53View FIGURES 46–54. 46).................................................................... Styxia Hull 

- Eye usually bare; if eye pilose, then abdominal pattern Syrphus  -like ( Fig. 55View FIGURES 55–61. 55). Wing never as above................... 15

15. Metasternum pilose. Face broad, broader than a 1/3 of the head’s width ( Fig. 57View FIGURES 55–61. 55). Flies with oval, parallel-sided or slightly petiolate abdomens ( Figs 55, 56View FIGURES 55–61. 55); some species with an abdominal pattern similar to the abdominal pattern of genus Syrphus  ( Fig. 55View FIGURES 55–61. 55). Male phallus with long spines apically ( Fig. 58dView FIGURES 55–61. 55) or postgonite bifurcate ( Fig. 60cView FIGURES 55–61. 55) or postgonite tooth-like ( Fig. 58cView FIGURES 55–61. 55, 5 9cView FIGURES 1–10. 1)............................................................................... Orphnabaccha Hull  , in part [Note: There are species with very few pile and it is not uncommon for them to eventually fall, making the metasternum look bare (e.g. species from the O. coerulea  species group).]

- Metasternum never pilose. Face narrower, usually around a 1/3 or less of head’s width. Abdomen variable, never similar to Syrphus  . Male genitalia never with long spines on phallus, never with a bifurcate or tooth-like postgonite............... 16

16. Abdominal terga 3 and 4 with yellow ‘L’ shaped markings ( Fig. 30View FIGURES 20–31. 20). Male genitalia usually enlarged.............................................................................................. Ocyptamus callidus  species group

- Abdominal terga never as above. Male genitalia variable..................................................... 17

17. Metaepisternum bare. Abdomen parallel-sided to slightly constricted, with inverted V-shaped yellow fascia on terga 3 and 4, sometimes interrupted medially ( Fig. 61View FIGURES 55–61. 55)................................................. Pipunculosyrphus Hull 

- Metaepisternum usually pilose ( Fig. 11View FIGURES 11–19. 11); if metaepisternum bare, then abdomen differently marked................... 18

18. Vein M1 sinuous ( Figs 71, 72, 73View FIGURES 71–77. 71); other characters not found in the combination below............................. 20

- Vein M1 straight, joining vein R4+5 perpendicularly ( Figs 62, 65View FIGURES 62–70. 62); wing either hyaline with an apical brown macula, or uniformly yellowish to brown. Small flies usually with short abdomen, shorter than wings............................. 19

19. Scutum shining black with three narrow white pollinose vittae, medial vitta longer ( Fig. 63View FIGURES 62–70. 62). Wing hyaline with apical dark macula, extensively bare ( Fig. 62View FIGURES 62–70. 62). Scutellum partially black. Abdominal terga 3 and 4, at least, black with five narrow pale vittae ( Fig. 63View FIGURES 62–70. 62)........................................................................ Calostigma Shannon 

- Scutum usually dull ( Fig. 67View FIGURES 62–70. 62); if shining black, then without distinct pattern ( Fig. 64View FIGURES 62–70. 62). Wing never as above, usually brownish yellow, extensively microtrichose ( Fig. 65View FIGURES 62–70. 62). Abdominal terga mostly pale with three apical dark vittae ( Fig. 66View FIGURES 62–70. 62) or dark with at most four pale vittae ( Figs 67, 68, 69View FIGURES 62–70. 62), never with five pale vittae................ Ocyptamus lepidus  species group, in part

20. Vein R4+5 almost straight; vein M1 not strongly sigmoid ( Figs 73View FIGURES 71–77. 71, 94View FIGURES 92–98. 92). Male genitalia never with enlarged nor elongate cercus. Other characters not found in the combination below........................................................ 22

- Vein R4+5 and M1 distinctly sinuous ( Figs 71, 72View FIGURES 71–77. 71): vein R4+5 with shallow dip into cell r4+5, and vein M1 strongly sigmoid. Frontoantennal area protruded, prominent ( Fig. 75View FIGURES 71–77. 71). Abdomen strongly petiolate ( Figs 71, 72View FIGURES 71–77. 71). Male genitalia enlarged ( Fig. 74View FIGURES 71–77. 71)..................................................................................................... 21

21. Metacoxa and metatrochanter with tuft of thick pile ( Fig. 74View FIGURES 71–77. 71). Male genitalia with cercus greatly enlarged ( Fig. 76View FIGURES 71–77. 71). Basoflagellomere elongate, much longer than broad, acute apically ( Figs 72, 74View FIGURES 71–77. 71). Large flies, greater than 12 mm ... Mimocalla Hull 

- Metacoxa and metatrochanter without tuft of thick pile ( Fig. 75View FIGURES 71–77. 71). Male genitalia with normal-sized cercus ( Fig. 77View FIGURES 71–77. 71). Basoflagellomere oval, about as long as broad ( Figs 71, 75View FIGURES 71–77. 71). Medium-sized flies, about 11 mm .... placiva Williston  [incertae sedis]

22. Ocellar triangle never contrasted as below, either entirely pale pollinose ( Fig. 79View FIGURES 78–84. 78) or with sparse pollinosity ( Fig. 80View FIGURES 78–84. 78). Dorsal occiput pilosity variable............................................................................... 24

- Ocellar triangle dull black pollinose, surrounded by dense pale pollinosity ( Fig. 78View FIGURES 78–84. 78). Dorsal occiput with a single row of pile ( Fig. 78View FIGURES 78–84. 78) ( Hybobathus  )................................................................................ 23

23. Scutum covered by dense pale pollinosity, with sub-shining vittae ( Figs 73View FIGURES 71–77. 71, 81View FIGURES 78–84. 78). Medium-sized flies (7–10 mm)................................................................................... Hybobathus Enderlein  sensu stricto

- Scutum black with three golden pollinose vittae that merge posteriorly into a pollinose area anterior to scutellum ( Fig. 82View FIGURES 78–84. 78). Larger flies (11–18 mm)........................................................ Hybobathus arx  species group

24. Abdomen long, almost as long as wing, parallel-sided with subbasal yellow fascia on terga 3–5 ( Fig. 83View FIGURES 78–84. 78). Alula narrow and linear (almost uniform width throughout), approximate length:width ratio = 5:1 (see Vockeroth 1969: Fig. 13View FIGURES 11–19. 11); wing infuscate ( Fig. 83View FIGURES 78–84. 78).......................................................... Hermesomyia wulpiana (Lynch Arribálzaga) 

- Abdomen variable, never with the above character combination. Alula variable................................... 25

25. Orange flies with narrow abdomen ( Fig. 85View FIGURES 85–91. 85). Male with a pair of long apicolateral extensions on sternum 4............................................................................. Ocyptamus melanorrhinus  species group, in part

- If the abdomen is narrow, then the overall body color is dark brown to black ( Figs 86, 87View FIGURES 85–91. 85), never orange. Male without such extensions on sternum 4............................................................................... 26

26. Abdomen usually petiolate, with narrow base and abruptly widening ( Fig. 89View FIGURES 85–91. 85) or very narrow and very long, delicate (2nd abdominal segment ≥ 8 times longer than wide; Fig. 84View FIGURES 78–84. 78); if abdomen parallel-sided, narrow and elongated, then tergum 3 never with a pair of subbasal quadrangular / triangular maculae..................................................... 28

- Abdomen parallel-sided, narrow but not delicate (2nd abdominal segment ≤ 6 times longer than wide) and elongated ( Figs 87, 88View FIGURES 85–91. 85), slightly expanding apically; tergum 3 with subbasal pair of quadrangular / triangular maculae that sometimes form a complete fascia.......................................................................................... 27

27. Wing hyaline with a central, triangular dark vitta; alula present ( Figs 86, 88View FIGURES 85–91. 85)......... Ocyptamus fascipennis  species group

- Wing either entirely hyaline or light brown; alula absent ( Fig. 87View FIGURES 85–91. 85)......... Ocyptamus melanorrhinus  species group, in part

28. Scutum yellow laterally ( Fig. 64View FIGURES 62–70. 62); scutellum usually yellow, rarely mostly dark. Wing usually light yellow. Abdomen either spatulate, parallel-sided or petiolate ( Figs 67, 68, 69View FIGURES 62–70. 62 respectively), never narrow and delicate. Male genitalia: subepandrial sclerite extended beyond base of surstyli as pair of lobes ( Fig. 31View FIGURES 20–31. 20); if subepandrial sclerite not extended beyond base of surstyli, then M1 joining R4+5 at right angle ( Fig. 65View FIGURES 62–70. 62).................................. Ocyptamus lepidus  species group

- Scutum and scutellum usually entirely black ( Fig. 90View FIGURES 85–91. 85); if scutum yellow laterally or scutellum mostly yellow, then either scutum with a distinct pattern of golden pollinose vittae on a black background and abdominal terga with a central pair of pale oval-shaped vittae ( Fig. 91View FIGURES 85–91. 85), or abdomen very narrow and delicate (2nd abdominal segment ≥ 8 times longer than wide; Figs 70View FIGURES 62–70. 62, 84View FIGURES 78–84. 78). Wings hyaline or mostly dark brown. Abdomen either petiolate ( Fig. 91View FIGURES 85–91. 85) or very narrow, long and delicate ( Figs 70View FIGURES 62–70. 62, 84View FIGURES 78–84. 78). Male genitalia: subepandrial sclerite never extended beyond base of surstyli as pair of lobes and vein M1 never straight.... 29 29. Abdomen very narrow and delicate through all its extent (2nd abdominal segment ≥ 8 times longer than wide; Figs 70View FIGURES 62–70. 62, 84View FIGURES 78–84. 78). Frons or frontal triangle usually rugose ( Figs 70View FIGURES 62–70. 62, 92View FIGURES 92–98. 92). Alula absent ( Fig. 94View FIGURES 92–98. 92). Male surstylus quadrangular and either with extended apex or apical filiform projection ( Fig. 95View FIGURES 92–98. 92); female tergum 7 without apodemes ( Fig. 97View FIGURES 92–98. 92)............................................................................................ Ocyptamus stenogaster  species group

- Abdomen usually petiolate ( Fig. 91View FIGURES 85–91. 85). If alula absent, abdomen very narrow and delicate, and frons and frontal triangle rugose, then face mostly dark ( Fig. 93View FIGURES 92–98. 92), male surstylus subtriangular without projection ( Fig. 96View FIGURES 92–98. 92), and female tergum 7 with long basolateral apodemes ( Fig. 98View FIGURES 92–98. 92).............................................................................. 30

30. Scutum usually pale laterally, with three golden pollinose vittae on a black background: middle vitta usually complete and narrow, others tapered and incomplete, not reaching the scutellum ( Figs 91View FIGURES 85–91. 85, 99View FIGURES 99–105. 99). Female segment 6 usually with weak fusion line at least on basal 1/2 ( Fig. 101View FIGURES 99–105. 99)................................................. Pelecinobaccha Shannon  , in part [Note: The P. summa  species group keys out here.]

- Scutum without distinct patterns of pollinosity and entirely dark ( Figs 89View FIGURES 85–91. 85, 100View FIGURES 99–105. 99). Female segment 6 divided into tergum and sternum or as a single conical sclerite ( Fig. 102View FIGURES 99–105. 99)............................................................ 31

31. Metabasitarsomere with at least basal 1/2 dark or mostly dark ( Fig. 103View FIGURES 99–105. 99)......................................... 33

- Metabasitarsomere wholly pale or mostly pale ( Fig. 104View FIGURES 99–105. 99)..................................................... 32

32. Pro and mesolegs mostly dark ( Figs 104, 105View FIGURES 99–105. 99). Abdomen dark with flat, scale-like, shinning pile ( Figs 56View FIGURES 55–61. 55, 105View FIGURES 99–105. 99).......................................................................................... Orphnabaccha Hull  , in part [Note: Orphnabaccha  species, mostly from the O. coerulea  species group, may key out here if the male genitalia characters are not checked or the metasternum pilosity is overlooked or looks bare.]

- Pro and mesolegs mostly pale. Abdomen with yellow vittae and dark pile ( Fig. 112)............................................................................................. Ocyptamus pola (Curran)  [ O. lepidus  species group] [Note: Ocyptamus pola  belongs to the O. lepidus  species group, but its particular morphology may create confusion with Pelecinobaccha  or Relictanum  . It is keyed out here to avoid misidentification.]

33. Dorsal occiput with two or more rows of pile, anterior row sometimes short but still distinct ( Figs 7View FIGURES 1–10. 1, 106View FIGURES 106–111. 106). Female segment 6 usually modified into a single conical sclerite with no distinction between tergum and sternum ( Fig. 102View FIGURES 99–105. 99)........................................................................................... Pelecinobaccha Shannon  , in part

- Dorsal occiput with a single row of pile ( Fig. 107View FIGURES 106–111. 106). Female 6th segment divided into tergum and sternum...................................................................................................... Relictanum  Miranda 

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Diptera

Family

Syrphidae