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. 1 View Figure ). Postmetacoxal bridge incomplete ( Fig. 11 View Figure ) or complete ( Figs 3, 4 View Figure ). 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. 2 View Figure ). Metepimera continuous behind metacoxae and forming a complete postmetacoxal bridge ( Figs 3, 4 View Figure ). Vein M1 very abruptly and strongly sinuate; vein R4+5 slightly to strongly sinuate ( Figs 5, 6 View Figure ).................................................................. 2

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

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

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

- Anterior anepisternum ( Fig. 12 View Figure ) and metaepisternum bare...................................................... 4

4 Oral margin at the same level of facial tubercle, in lateral view ( Fig. 12 View Figure ); 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. 13 View Figure ); if facial tubercle is missing, then face always pointed forward and oral margin beyond the medial point between oral margin and antennal bases ( Fig. 14 View Figure ). Postpronotum yellow; notopleuron usually yellow; pleuron more extensively yellow ( Fig. 13 View Figure )....................................... Rhinoprosopa Hull 

5 Male genitalia: phallus (aedeagus) simple, unsegmented. Face usually straight, oral margin and antennal bases in line, without tubercle ( Figs 15, 18 View Figure ). Abdomen petiolate; abdominal tergum 2 narrow, narrower than terga 3 and 4 ( Fig. 18 View Figure ). 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 58–60 View Figure , 111 View Figure ). Face usually with a facial tubercle ( Figs 16 View Figure , 32 View Figure ), at least slightly convex ( Figs 17 View Figure ). Abdomen variable. Female: abdominal segment 6 conspicuous, easily visible.... 6

6 Face gently convex; facial tubercle weak ( Fig. 17 View Figure ); metaepisternum bare; abdomen petiolate ( Fig. 19 View Figure )............................................................................................... 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. 20 View Figure ). Ocellar triangle distanced from eye contiguity on male ( Fig. 21 View Figure ). Face convex or produced anteriorly ( Figs 20, 22 View Figure ). 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. 23 View Figure ) or a pattern derived from that ( Fig. 24 View Figure ), 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, 26 View Figure ).................................. Toxomerus Macquart 

- Posterior margin of eye with emargination usually indistinct or shallow and rounded ( Figs 27 View Figure , 32 View Figure ). Ocellar triangle touching eye contiguity on male ( Figs 28 View Figure , 57 View Figure , 79 View Figure ). Face never produced anteriorly. Abdomen variable; abdominal markings never derived from medial pair of stripes as above ( Figs 29, 30 View Figure ). Male genitalia without such single acute sclerotized process, at most with a bilobate process ( Fig. 31 View Figure ).......................................................................... 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, 37 View Figure )... 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. 38 View Figure ).......................................................................... 9

9. Basoflagellomere deeply incised, forming dorsal and ventral lobes ( Fig. 40 View Figure ). Male tergum 4 concave apically, so apical abdominal segments can be flexed dorsally; male sternum 4 produced greatly ventrally ( Figs 40, 41, 42 View Figure ). 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. 43 View Figure )................................... grata Curran  [incertae sedis]

- Basoflagellomere oval to elongate ( Figs 27 View Figure , 45 View Figure ). 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. 27 View Figure ). Abdominal terga 3 and 4 with a subbasal yellow fascia and a pair of oblique, pale vittae ( Fig. 44 View Figure ).............................. conjunctus Wiedemann  [incertae sedis]

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

11. Abdomen parallel-sided, elongate, mainly orange and without a distinct pattern of markings ( Fig. 38 View Figure ); tergum 2 with basolateral hyaline areas. Metafemur pale with long, thick, mostly orange pile on dorsal and ventral surface ( Fig. 39 View Figure ), 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. 103 View Figure ) and abdominal terga with four pale vittae............................................................. 12

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

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

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

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

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

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

15. Metasternum pilose. Face broad, broader than a 1/3 of the head’s width ( Fig. 57 View Figure ). Flies with oval, parallel-sided or slightly petiolate abdomens ( Figs 55, 56 View Figure ); some species with an abdominal pattern similar to the abdominal pattern of genus Syrphus  ( Fig. 55 View Figure ). Male phallus with long spines apically ( Fig. 58d View Figure ) or postgonite bifurcate ( Fig. 60c View Figure ) or postgonite tooth-like ( Fig. 58c View Figure , 5 9c View Figure )............................................................................... 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. 30 View Figure ). 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. 61 View Figure )................................................. Pipunculosyrphus Hull 

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

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

- Vein M1 straight, joining vein R4+5 perpendicularly ( Figs 62, 65 View Figure ); 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. 63 View Figure ). Wing hyaline with apical dark macula, extensively bare ( Fig. 62 View Figure ). Scutellum partially black. Abdominal terga 3 and 4, at least, black with five narrow pale vittae ( Fig. 63 View Figure )........................................................................ Calostigma Shannon 

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

20. Vein R4+5 almost straight; vein M1 not strongly sigmoid ( Figs 73 View Figure , 94 View Figure ). 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, 72 View Figure ): vein R4+5 with shallow dip into cell r4+5, and vein M1 strongly sigmoid. Frontoantennal area protruded, prominent ( Fig. 75 View Figure ). Abdomen strongly petiolate ( Figs 71, 72 View Figure ). Male genitalia enlarged ( Fig. 74 View Figure )..................................................................................................... 21

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

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

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

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

23. Scutum covered by dense pale pollinosity, with sub-shining vittae ( Figs 73 View Figure , 81 View Figure ). 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. 82 View Figure ). 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. 83 View Figure ). Alula narrow and linear (almost uniform width throughout), approximate length:width ratio = 5:1 (see Vockeroth 1969: Fig. 13 View Figure ); wing infuscate ( Fig. 83 View Figure ).......................................................... Hermesomyia wulpiana (Lynch Arribálzaga) 

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

25. Orange flies with narrow abdomen ( Fig. 85 View Figure ). 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, 87 View Figure ), never orange. Male without such extensions on sternum 4............................................................................... 26

26. Abdomen usually petiolate, with narrow base and abruptly widening ( Fig. 89 View Figure ) or very narrow and very long, delicate (2nd abdominal segment ≥ 8 times longer than wide; Fig. 84 View Figure ); 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, 88 View Figure ), 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, 88 View Figure )......... Ocyptamus fascipennis  species group

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

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

- Scutum and scutellum usually entirely black ( Fig. 90 View Figure ); 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. 91 View Figure ), or abdomen very narrow and delicate (2nd abdominal segment ≥ 8 times longer than wide; Figs 70 View Figure , 84 View Figure ). Wings hyaline or mostly dark brown. Abdomen either petiolate ( Fig. 91 View Figure ) or very narrow, long and delicate ( Figs 70 View Figure , 84 View Figure ). 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 70 View Figure , 84 View Figure ). Frons or frontal triangle usually rugose ( Figs 70 View Figure , 92 View Figure ). Alula absent ( Fig. 94 View Figure ). Male surstylus quadrangular and either with extended apex or apical filiform projection ( Fig. 95 View Figure ); female tergum 7 without apodemes ( Fig. 97 View Figure )............................................................................................ Ocyptamus stenogaster  species group

- Abdomen usually petiolate ( Fig. 91 View Figure ). If alula absent, abdomen very narrow and delicate, and frons and frontal triangle rugose, then face mostly dark ( Fig. 93 View Figure ), male surstylus subtriangular without projection ( Fig. 96 View Figure ), and female tergum 7 with long basolateral apodemes ( Fig. 98 View Figure ).............................................................................. 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 91 View Figure , 99 View Figure ). Female segment 6 usually with weak fusion line at least on basal 1/2 ( Fig. 101 View Figure )................................................. Pelecinobaccha Shannon  , in part [Note: The P. summa  species group keys out here.]

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

31. Metabasitarsomere with at least basal 1/2 dark or mostly dark ( Fig. 103 View Figure )......................................... 33

- Metabasitarsomere wholly pale or mostly pale ( Fig. 104 View Figure )..................................................... 32

32. Pro and mesolegs mostly dark ( Figs 104, 105 View Figure ). Abdomen dark with flat, scale-like, shinning pile ( Figs 56 View Figure , 105 View Figure ).......................................................................................... 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 7 View Figure , 106 View Figure ). Female segment 6 usually modified into a single conical sclerite with no distinction between tergum and sternum ( Fig. 102 View Figure )........................................................................................... Pelecinobaccha Shannon  , in part

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

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Diptera

Family

Syrphidae