Syringogaster, Cresson, 1912

Marshall, S. A., Buck, M., Skevington, J. H. & Grimaldi, D., 2009, A revision of the family Syringogastridae (Diptera: Diopsoidea), Zootaxa 1996 (1), pp. 1-80 : 16-18

Key to the extant species of Syringogaster

1. Wing extensively infuscated (including apex), with three transverse white spots between crossveins and between dm-cu and wing tip ( Plate 2). Crossvein dm-cu at least 2.8X (usually at least 3X) as long as r-m. Anepimeron tomentose .................................................................................................................................................. S. brunnea -group 2

– Wing mostly clear (including apex) with three more or less intense brown fasciae at level of crossveins (two distal fasciae often coalesced) ( Plate 3). Crossvein dm-cu at most 2.5X (usually 2.0X or less) as long as r-m. Anepimeron shining......................................................................................................................................................................... 10

2. Ocellar bristles absent or minute. Fore femur with distal anteroventral spinules ( Plate 6A). Surstylus straight, slightly expanded distally (e.g., Fig. 17)....................................................................................................................... 3

– Ocellar bristles well-developed. Fore femur with or without distal ventral spinules. Surstylus parallel-sided or tapered distally (e.g., Fig. 43), sometimes ( S. carioca ) strongly bent .......................................................................... 5

3. Thorax mostly reddish brown. Fore femur with 1–5 (usually less than 5) anteroventral spinules ( Guatemala to Ecuador, west of the Andes) .................................................................................................................... S. brunnea Cresson

– Thorax largely black. Fore femur with 3–12 (almost always more than 5) anteroventral spinules ............................. 4

4. Ocellar triangle shining and bare in contrast with tomentose lower frons (as in Plate 5D). Fore femur with 10–12 anteroventral spinules. Meron, metapleuron and metasternum tomentose. Apex of hind tibia with large, anteroventral, rounded projection (its length nearly equal to width of basitarsus). Male tergite 5 simple, without prominent ventrolateral lobe on left side. Right posterolateral corner of male tergite 5 not projecting ( Ecuador) ......................... ............................................................................................................... S. nigrithorax Marshall & Buck , new species

– Ocellar triangle tomentose, similar to surrounding areas. Fore femur with 3–8 anteroventral spinules. Meron, metapleuron and metasternum largely shining, bare ( Plate 2D). Apex of hind tibia angulate anteroventrally but angle hardly projecting. Male tergite 5 with prominent ventrolateral lobe on right side ( Fig. 57). Right posterolateral corner of male tergite 5 strongly projecting posteriorly ( Mexico to Costa Rica) ............................. S. subnearctica Feijen

5. Fore femur without anteroventral spinules. Ocellar triangle tomentose or shining. Apex of basiphallus with a fingerlike lobe on left side (e.g., Fig. 24). Female tergite 7 with deep posteromedial emargination..................................... 6

– Distal part of fore femur with anteroventral spinules. Ocellar triangle shining. Apex of basiphallus with a wide lobe on left side or without lobes. Female tergite 7 with or without posteromedial emargination....................................... 8

6. Ocellar triangle shining (as in Plate 5E). Fore tarsus contrastingly coloured, basal 4/5 of tarsomere 1 dark brown, remainder of tarsus whitish. Proepisternum entirely shining. Posterior tomentose area of anepisternum extending anteriorly to about halfway level between posterior margins of anepisternum and postpronotum. Thorax mostly reddish ( Ecuador, Peru; east of the Andes) ...................................................... S. sharkeyi Marshall & Buck , new species

– Ocellar triangle tomentose. Fore tarsus yellow, tarsomere 1 hardly darker. Proepisternum tomentose on dorsal half. Posterior tomentose area of anepisternum reaching level of posterior margin of postpronotum. Thorax reddish or predominantly dark ....................................................................................................................................................... 7

7. Thorax mostly dark brown ( Plate 2F). Surstylus tapered apically, at least twice as long as cercus ( Figs. 43, 44) ( Colombia, Ecuador west of the Andes) .................................................... S. palenque Marshall & Buck , new species

– Thorax mostly reddish brown ( Plate 2G). Surstylus wide apically, less than twice as long as cercus ( Figs. 21, 22) ( Guatemala and Trinidad to Colombia east of the Andes) ....................... S. brunneina Marshall & Buck , new species

8. Hind femur bicolored beyond white base: yellowish distal, dorsal tomentose area contrasting with dark brown to black remainder of femur ( Plate 2E) ( Brazil, Bolivia) ............................................................................ S. lopesi Prado

– Hind femur (including distal, dorsal tomentose area) more or less concolorous reddish brown beyond narrow white base ............................................................................................................................................................................... 9

9. Thorax almost entirely black or dark brown ( Plate 6A). Fore tibia and tarsus yellowish. Lateral portions of male tergite 5 forming prominent, apically expanded, projecting lobes. Surstylus abruptly bent distally ( Fig. 28) ( Venezuela to Brazil, Ecuador, Peru) ................................................................................................................ S. carioca Prado

– Thorax mostly pale brown, especially anterior portion ( Plate 2C). Fore tibia and basal ¾ of fore tarsomere 1 dark. Lateral portions of male tergite 5 simple. Surstylus nearly straight ( Fig. 32) ( Brazil, Peru, Suriname, Bolivia) .......... ............................................................................................................................................................. S. cressoni Prado

10. Ocellar bristles absent ................................................................................................................................................. 11

– Ocellar bristles present (often broken off but sockets distinct) .................................................................................. 12

11. Anepisternum and katepisternum largely dull, tomentose. Wing infuscation more extensive, distal two fasciae broadly connected, infuscation around dm-cu broad and strong. Prespiracular process stout and conical, tomentose and setulose ( Brazil, Bolivia) .................................................................................................................... S. lanei Prado

– Pleuron entirely shining, without tomentum. Wing infuscation more restricted, distal two fasciae not connected, infuscation around dm-cu weak ( Plate 3D). Prespiracular process long, finger-like, shining and without setulae ( Plate 4C) ( Ecuador to Bolivia) ......................................................... S. dactylopleura Marshall & Buck , new species

12. Syntergite 1–3 gradually widening from base, not parallel-sided in basal half (similar to Fig. 63). A 1 +CuA 2 absent or extending much less than half way to wing margin ( Plate 3F). Crossvein dm-cu straight or nearly straight ............ 13

– Abdomen strongly petiolate, syntergite 1–3 narrow and parallel-sided at least on basal half ( Fig. 19). A 1 +CuA 2 extending far beyond corner of anal cell, reaching at least half way to wing margin ( Plate 3G, Figs. 73–75). Crossvein dm-cu usually strongly curved ( Plate 3G) .......................................................................................................... 16

13. Thorax dark brown to black........................................................................................................................................ 14

– Thorax largely reddish brown, dark brown area more or less restricted to metathorax ( Plate 6B) ............................ 15

14. Crossvein bm-cu distal to fork of CuA; A 1 +CuA 2 short but present; posteroapical corner of anal cell appendiculate. Fore femur with a row of 7 short anteroventral spinules; fore tarsus yellow ( Brazil, known from female only) .......... ..................................................................................................................................................... S. amazonensis Prado

– Crossvein bm-cu either at level of, or basal to fork of CuA; A 1 +CuA 2 completely absent; posteroapical corner of anal cell narrowly rounded ( Plate 3A). Fore femur with a row of 10–16 short anteroventral spinules; fore tarsus contrastingly coloured, at least basal half of tarsomere 1 dark brown, remainder of tarsus whitish ( Plate 1E) ( Ecuador to Bolivia, Brazil) ........................................................................................... S. atricalyx Marshall & Buck , new species

15. Fore basitarsus (sometimes excluding apex) dark brown, contrasting with whitish distal tarsomeres ( Plate 3H). Ocellar triangle broadly rounded anteriorly ( Plate 5D) ( Ecuador, Peru) ........ S. plesioterga Marshall & Buck , new species

– Fore basitarsus yellowish, more or less unicolorous with distal tarsomeres ( Plate 3F). Ocellar triangle somewhat pointed anteriorly ( Costa Rica) .................................................................... S. figurata Marshall & Buck , new species

16. Fore femur with 4–5 anteroventral spinules distally. Katepisternum largely tomentose except dorsally and posteriorly. CuA 1 extending less than half way to wing margin. Crossvein dm-cu straight or weakly curved ( Brazil) ........... .......................................................................................................................................................... S. papaveroi Prado

– Fore femur without ventral spinules. Katepisternum shining. CuA 1 extending almost to wing margin. Crossvein dmcu strongly curved ( Plate 3G) .............................................................................................................. S. rufa -group 17

17. Hind femur with anteroventral spines restricted to less than distal half of femur ( Plate 3C). Male fore femur posteroventrally with numerous (>25) long hairs in more than two rows. Epandrium longer than wide ( Fig. 14). Ventral hypandrial lobe densely setose, without stout apical bristles ( Fig. 16). Each pair of spermathecae broadly fused, tireshaped ( Ecuador) ................................................................................... S. brachypecta Marshall & Buck , new species

– Hind femur with anteroventral row of spines extending at least to middle of femur. Male fore femur posteroventrally with sparse (<15) long hairs in 1–2 rows. Epandrium wider than long (e.g., Fig. 5). Ventral hypandrial lobe with some stout apical bristles as well as thin hairs (e.g., Fig. 53). Spermathecae closely paired but not fused ( Plate 3G) .................................................................................................................................................................................... 18

18. Abdominal tergites 3–6 orange-brown, tergites 4 and 5 sometimes slightly darker laterally. Vertex not strikingly angulate (fronto-occipital angle greater than 90°). Anteroventral apical corner of hind tibia not strongly produced. Basal 2/3 of male fore femur with numerous ventral and posterior hairs; hairs longer than diameter of femur ( Costa Rica, Panama, Ecuador west of the Andes) ........................................................................................... S. rufa Cresson

– Abdominal tergites 4–6 and usually part of tergite 3 dark brown. Vertex strongly angulate in lateral view (frontooccipital angle less than 90°) ( Plate 3E). Anteroventral apical corner of hind tibia angulate, produced. Base of male fore femur at most with 1–2 ventral hairs that are longer than diameter of femur ( Ecuador to Bolivia, east of the Andes) ......................................................................................................................................................................... 19

19. Hind femur stout, 3.5–4.0X as long as wide (lateral view) ( Plate 3E), with 8–10 spines in anteroventral row. Apex of basiphallus with a broad, rounded lateral expansion on right side ( Fig. 8). Distiphallus lacking lamellate projection below large, sickle-shaped apical lobe ( Fig. 6) ( Ecuador, Peru) ............... S. apiculata Marshall & Buck , new species

– Hind femur slender, 4.1–4.7X as long as wide, with 5–7 spines in anteroventral row. Apex of basiphallus without lateral expansion on right side ( Figs. 60, 62). Distiphallus with apically notched, lamellate projection below large, sickle-shaped apical lobe ( Fig. 61) ( Ecuador to Bolivia) ............................ S. tenuipes Marshall & Buck , new species