Syzeuctus FÖRSTER, 1868

Riedel, Matthias, 2021, The genus Syzeuctus FÖRSTER in the Western Palaearctic region and Central Asia (Hymenoptera, Ichneumonidae, Banchinae), with descriptions of 17 new species, Linzer biologische Beiträge 52 (2), pp. 1013-1098 : 1015-1020

Key to the West Palaearctic and Central Asian species of Syzeuctus FÖRSTER

♀♀ (unknown for S. flavator ):

1. Frons with two sublateral horns. .........................................................................................2

- Frons without distinct sublateral horns, but often ± swollen laterally and impressed medially, sometimes with short lateral transversal ridges or tubercles ( S. flagellator runs through both alternatives). ...........................................................................................5

2. Hind femur black. 2 nd and 3 rd tergites longer than wide. Ovipositor 2.0-2.1× longer than fore wing. Temple strongly narrowed behind eye. Face black. Mesosoma black, without yellow coloration. Basal tergites reddish. Length 11-13 mm. Europe. ..................... ........................................................................................ S. bicornis ( GRAVENHORST, 1829)

- Hind femur red. 2 nd and 3 rd tergites square or wider than long. Ovipositor shorter, not more than 1.25× longer than fore wing. ..............................................................................3

3. Tegula and anterolateral mark on mesoscutum yellow. Hind tibia red, yellow basally and ± infuscate apically. 1 st to 4 th tergites red. Spain............................. S. leo SEYRIG, 1926

- Mesosoma including tegula black. 4 th tergite black or red basally. .....................................4

4. Ovipositor shorter, 0.85-0.9× as long as fore wing. Frons with distinct sublateral horns. Hind tibia brownish, reddish basally. 1 st tergite apically, 2 nd and 3 rd tergite entirely and 4 th tergite basally red. Spain.............................................................. S. caper SEYRIG, 1927

- Ovipositor longer, 1.2-1.25× longer than fore wing. Frons moderately swollen laterally or with sublateral tubercles, but without distinct horns. Hind tibia reddish-yellow basally, black in apical half. 2 nd and 3 rd tergites red, sometimes 4 th tergite red basally (fig. 13). France and Switzerland. ............................................... S. flagellator nov.sp., part

5. Apical transversal carina of propodeum complete, sometimes shortly obsolete medially...............................................................................................................................6

- Apical transversal carina entirely absent or widely interrupted medially. .........................32

6. Head and mesosoma black or with very limited yellow coloration (fig. 2). Metasoma black, with some ± reddish basal tergites, without distinct apical yellow bands. ................7

- Head and mesosoma usually with extended yellow coloration (figs 3, 6), if yellow coloration reduced, than tergites black and often with yellow apical bands (fig. 35). ........... ..........................................................................................................................................15

7. Ovipositor very long, about 2× longer than fore wing. Legs including coxae and trochanters entirely red. Ocelli large, OED 0.9× ocellar diameter (fig. 133). Serbia............. ............................................................................................................... S. ruficoxis nov.sp.

- Ovipositor shorter, at most 1.5× longer than fore wing. Coxae and trochanters usually black and/or yellowish. Ocelli variable ...............................................................................8

8. Antenna with 31-33 flagellomeres Metasoma stout; 2 nd and 3 rd tergites wider than long (figs 25, 31). Fore wing hyaline. ........................................................................................9

- Antenna with at least 35 flagellomeres. 2 nd and 3 rd tergites sometimes longer than wide. Fore wing sometimes with subapical brown spot..............................................................10

9. Genal carina low ventrally. Frons usually with ± distinct sublateral tubercles. Mesosoma including tegula black (fig. 2). Ovipositor 1.2-1.25× longer than fore wing. Length 8.5-9.5 mm. France, Switzerland. ................................... S. flagellator nov.sp., part

- Genal carina lamelliform widened ventrally. Frons without sublateral tubercles. Mesosoma with some yellow coloration (fig. 1). Ovipositor 0.8-0.9× as long as fore wing. Length 9 mm. Kyrgyzstan. ..................................................... S. altaicus nov.sp., part

10. Tegula yellow or red. Fore wing with subapical brown spot.............................................11

- Tegula black. Fore wing hyaline, sometimes with weak apical spot. ................................12

11. Metasoma less stout; 1 st tergite 1.5-1.9× longer than wide. OED 1.5-1.8× ocellar diameter. Ovipositor 1.1-1.4× longer than fore wing. Antenna with 37-41 flagellomeres. Length 10-12 mm. ...................... S. maculipennis f. lunigera BRAUNS, 1888

- Metasoma very stout; 1 st tergite 1.2× longer than wide. OED 1.7× ocellar diameter. Ovipositor as long as fore wing. Antenna with 36 flagellomeres. Length 9-10 mm .............. ........................................................................................... S. vigil ( TOSQUINET, 1900) , part

12. Ocelli small, OED 2.0-2.6× ocellar diameter (fig. 110). Antenna with 40-44 flagellomeres. Hind femur black or red. 1 st tergite 1.5-1.7× longer than wide, 2 nd and 3 rd tergites ± square. Ovipositor 1.0-1.4× longer than fore wing. Length 9-12 mm. Palaearctis ................................................................... S. exsculptus ( FONSCOLOMBE, 1854)

- Ocelli larger, OED at most 1.7× ocellar diameter. ............................................................13

13. Hind femur blackish, slender, 5.9× longer than wide 1 st tergite entirely red (fig. 35). Length 9.5 mm. Far East Russia, Mongolia. ................... S. hyalinipennis SZÉPLIGETI, 1901

- Hind femur red, stouter, not more than 5.0× longer than wide. 1 st tergite often black basally. ..............................................................................................................................14

14. 2 nd to 4 th tergites red, 5 th and 6 th tergites black. Propodeum densely punctate (fig. 99). Ovipositor c. 1.0× as long as fore wing. Length 10-11 mm. Palaearctis. .............................. ...................................................................................... S. petiolaris ( GRAVENHORST, 1829)

- 2 nd to 6 th tergites red. Propodeum densely rugose-punctate (fig. 98). Ovipositor 1.1- 1.2× longer than fore wing. Length 10 mm. Kazakhstan.............. S. kazakhstanicus nov.sp.

15. 2 nd hind tarsomere shorter or as long as 3 rd hind tarsomere (fig. 56). Hind femur stout, 4.1-4.4× longer than wide. Hind tarsomeres with strong apical bristles. Tergites red and yellow. Fore wing with brown subapical spot. .................................................................16

- 2 nd hind tarsomere at least 1.2× longer than 3 rd hind tarsomere.........................................17

16. 2 nd hind tarsomere shorter (0.9-0.95×) than 3 rd hind tarsomere. Malar space wide, MI 0.6-0.8. 2 nd and 3 rd tergites longer than wide. Antenna with 31-36 flagellomeres. Face entirely yellow. Length 7-10 mm. North Africa, Central Asia. ............................................. .............................................................................................. S. crassitarsis TELENGA, 1930

- 2 nd hind tarsomere about as long as 3 rd hind tarsomere. Malar space narrow, MI 0.25- 0.3. 2 nd and 3 rd tergites about square. Antenna with 35-36 flagellomeres. Face with central brown stripe. Length 11-12 mm. Mongolia. ........................... S. mongolicus nov.sp.

17. Ovipositor very long, more than 1.5× longer than fore wing. 2 nd and 3 rd tergites longer than wide. Fore wing with subapical brown spot. .............................................................18

- Ovipositor shorter, 0.8-1.5× as long as fore wing. ............................................................19

18. Fore and mid legs yellowish, with brown dorsal stripes. Antenna with 38-42 flagellomeres. Metasoma black or basal tergites ± reddish, usually 2 nd to 4 th tergites with distinct yellow apically bands. Ovipositor 1.6-2.0× longer than fore wing. Length 11-13 mm. Palaearctis. ......................................................... S. longivalvator AUBERT, 1977

- Legs including coxae and trochanters mainly red. Antenna with 34-42 flagellomeres. Metasoma red or brownish; 1 st to 3 rd tergites with diffuse reddish or yellowish apical bands (fig. 38). Ovipositor 1.75× longer than fore wing. 14 mm. Mongolia......................... ................................................................................................................. S. kabzabi nov.sp.

19. Antenna with 31 flagellomeres. Genal carina lamelliform widened ventrally. 2 nd and 3 rd tergites wider than long. Ovipositor 0.8-0.9× as long as fore wing. 2 nd to 4 th tergites red. Fore wing hyaline. Legs except black coxae and trochanters reddish (figs 1, 12). Length 9 mm. Kyrgyzstan. ............................................................... S. altaicus nov.sp., part

- Antenna with more flagellomeres. Ovipositor usually longer than fore wing. ..................20

20. Basal tergites ± red, without distinct yellow apical bands.................................................21

- Basal tergites black or red, often with distinct yellow apical bands. .................................24

21. Metasoma slender; 2 nd and 3 rd tergites longer than wide (fig. 27). ....................................22

- Metasoma stouter; 2 nd and 3 rd tergites wider than long (fig. 50). ......................................23

22. Fore wing with subapical brown spot. Mesoscutum densely and coarsely punctate. Hind femur usually red. 1 st to 3 rd tergites red, sometimes 1 st to 4 th tergites with apical yellow bands. Antenna with 37-41 flagellomeres. Length 10-12 mm. Palaearctis. ............... .................................................................................... S. maculipennis ( COSTA, 1883) , part

- Fore wing hyaline, without brown spot. Mesoscutum with scattered punctures anteriorly and almost smooth posteriorly (fig. 24). Hind femur black, narrowly yellow apically. Apical half of 1 st tergite, 2 nd tergite entirely and basal band of 3 rd tergite red. Antenna with 41 flagellomeres. Length 11 mm. Kazakhstan. ....... S. brevipunctatus nov.sp.

23. Fore wing with subapical brown spot. Ovipositor as long as fore wing. 1 st tergite 1.2× longer than wide, 2 nd and 3 rd tergites 1.2-1.3× wider than long (fig. 50). Hind femur 4.8-5.3× longer than wide, red. 1 st to 3 rd tergites black, with reddish-brown suffusion OR entirely red (f. rufus AUBERT). Length 9-10 mm. East Europe, Russia........................... ........................................................................................... S. vigil ( TOSQUINET, 1900) , part

- Fore wing hyaline, without brown spot. Ovipositor 1.3× longer than fore wing. 1 st tergite 1.3-1.4× longer than wide, with rather dense coarse punctures laterally. 2 nd tergite 1.0-1.15× wider than long, 3 rd tergite 1.1-1.2× wider than long (fig. 47). Hind femur 5.3-5.6× longer than wide. 1 st to 5 th tergites red, 6 th and 7 th tergites brownish. Length 9-10 mm. Kyrgyzstan................................................................ S. rufigaster nov.sp.

24. Antenna with 43-45 flagellomeres. Hind tibia brownish, with yellow external stripe; hind femur black, sometimes with yellow dorsal stripe. Frontal orbit with strongly widened yellow spot (figs 70, 113). OED 1.8× ocellar diameter. Hind femur slender, 5.9× longer than wide. Wing hyaline or with weak apical brown spot. Metasoma black or 1 st to 4 th tergites with narrow yellow bands. Ovipositor 1.1-1.2× longer than fore wing. Length 10-12 mm. Turkey, Syria. ................................................ S. frontator nov.sp.

- Antenna with lower number of flagellomeres. Hind tibia usually yellow, ± infuscate apically; hind femur variable. Frontal orbit often with ± narrow yellow stripe. ...............25

25. Metasoma entirely black or central tergites with narrow yellow-red apical margins. Antenna with 36-42 flagellomeres. Ovipositor 1.1-1.4× longer than fore wing. Coxae, trochanters and trochantelli black. All femora yellowish-red or red. Mesosoma often with reduced yellow marks. West Palaearctis ....................................................................... ............................................................................ S. tenuifasciatus SCHMIEDEKNECHT, 1900

- Basal tergites with ± distinct yellow apical bands. Mesosoma including propodeum with extended yellow marks. Fore and mid femora usually yellowish; hind femur black or red to reddish-brown, but always darker than mid femur..............................................26

26. Hind femur blackish (rarely red or reddish-brown), often yellow apically. 2 nd and 3 rd tergites longer than wide. Ovipositor as long as or slightly longer than fore wing. Antenna with less than 40 flagellomeres. ..........................................................................27

- Hind femur red OR yellow ventrally and brown or red dorsally. ......................................28

27. Hind trochantellus ± yellow. 1 st to 4 th tergites with wide apical yellow bands. Antenna with 37-38 flagellomeres. Frons with strong lateral swellings. Ovipositor 1.1-1.4× longer than fore wing. Europe. .................................................. S. bicolor SZÉPLIGETI, 1899

- Hind trochantellus usually dark-brown. 1 st to 3 rd tergites (rarely also 4 th tergite) with apical yellow bands. Antenna with 33-39 flagellomeres. Frons with slight lateral swellings. Ovipositor 1.0-1.4× longer than fore wing. West Palaearctis. .............................. ................................................................................................... S. fuscator ( PANZER, 1809)

28. Metasoma stout; 2 nd and 3 rd tergites slightly wider than long (figs 33, 36). Fore wing hyaline. Ovipositor 0.9-1.2× as long as fore wing. ...........................................................29

- Metasoma slenderer, 2 nd and 3 rd tergites at least as long as wide (fig. 41). Fore wing sometimes with brown spot. Ovipositor 1.1-1.5× longer than fore wing...........................30

29. Ovipositor 1.1-1.2× longer than fore wing. MI 0.9-1.0. Smaller, length 9-9.5 mm. Mongolia. ................................................................................................ S. hyalinus nov.sp.

- Ovipositor 0.9× as long as fore wing. MI 0.75-0.9. Larger, body length 10-11 mm. Eastern Europe. ......................................................................... S. decoratus ( COSTA, 1890)

30. Fore wing with subapical brown spot. Hind femur usually red. 1 st to 3 rd /4 th tergites red, 1 st to 4 th /5 th tergites with apical yellow bands. Antenna with 37-41 flagellomeres. Length 10-12 mm. West Palaearctis............................ S. maculipennis ( COSTA, 1883) , part

- Fore wing hyaline or with apical brown spot. ...................................................................31

31. Antenna with 38 flagellomeres. Temples shortly parallel behind eyes. Hind femur slender, 5.3× longer than wide. 2 nd and 3 rd tergites red, ± yellow apically, apical tergites brown (fig. 10). Ovipositor c. 1.2× longer than fore wing. Fore wing with apical brown spot. Length 11 mm. Iran. ....................................................... S. brunneomaculatus nov.sp.

- Antenna with 33-35 flagellomeres. Temples roundly narrowed behind eyes. Hind femur stouter, 4.8-4.9× longer than wide. Fore wing hyaline. Ovipositor 1.2-1.4× longer than fore wing. Tergites mainly red, with apical yellow bands on 1 st to 5 th tergites (fig. 45). Fore wing without distinct brown spot. Length 8-9.5 mm. China, Mongolia. ................................................................................. S. longigenus UCHIDA, 1940

32. Genal carina reaching hypostomal carina shortly before mandibular base. 2 nd to 3 rd /4 th tergites with separated triangular basomedian areas (fig. 49). Antenna with 28-32 flagellomeres. Ovipositor 1.05-1.15× longer than fore wing. Fore wing with apical brown spot. Length 8-10 mm. ............................................................ S. tigris SEYRIG, 1926

- Genal carina reaching mandibular base. 2 nd and 3 rd tergites without distinct basomedian areas. Ovipositor shorter or longer than fore wing. ..........................................................33

33. Antenna with 31 flagellomeres. Head and mesosoma largely yellow, with reduced blackish spots. Hind femur yellow. Metasoma red and yellow, stout; 2 nd and 3 rd tergites wider than long (fig. 29). Fore wing with weak subapical brown spot..............................34

- Antenna usually with more flagellomeres. Head and mesosoma usually with extended blackish coloration. Metasoma often ± blackish. ..............................................................35

34. Clypeus with central transversal ridge. MI 1.0 (fig. 62). Temple shorter, dorsally 0.3- 0.4× eye length. Metasoma mainly reddish, 1 st to 5 th tergites with yellow apical bands. Ovipositor shorter, 0.7× as long as fore wing. 9 mm. Egypt, Morocco. ................................ .............................................................................................. S. caudulator SHAUMAR, 1966

- Clypeus without central transversal ridge. MI 0.6. Temple longer, dorsally 0.5× eye length. Basal tergites reddish, apical tergites brown; all tergites with wide apical yellow bands. Ovipositor longer, about as long as fore wing. 9 mm. Egypt. .................................... ................................................................................ S. heluanensis SCHMIEDEKNECHT, 1900

35. 1 st tergite very stout, 1.25-1.5× longer than wide, 2 nd and 3 rd tergites wider than long (fig. 37). ............................................................................................................................36

- 1 st tergite slenderer, more than 1.5× longer than wide. 2 nd and 3 rd tergites ± longer than wide (fig. 48).....................................................................................................................37

36. Mesosoma with reduced yellow coloration; pronotum black. 1 st to 4 th /5 th tergites reddish. Ovipositor 1.2-1.4× longer than fore wing. Antenna with 37-41 flagellomeres. Length 10-11 mm. Europe........................................... S. inaequalis ( FONSCOLOMBE, 1854)

- Mesosoma with extended yellow coloration; pronotum ± yellow. Ovipositor 0.8-1.1× as long as fore wing. Tergites black (sometimes 2 nd and 3 rd tergites ± reddish), with apical yellow bands on 1 st to 4 th /5 th tergites. Antenna with 32-38 flagellomeres. Length 8-12 mm. West Palaearctis. ......................................................... S. irrisorius ( ROSSI, 1794)

37. Ovipositor 1.8× longer than fore wing. 1 st tergite slender, 1.45× longer than wide, 2 nd and 3 rd tergites distinctly longer than wide. 1 st to 3 rd tergite red, 4 th tergite only basally, without apical yellow bands (fig. 17). Basal cell of fore wing sparsely pilose. Length 11 mm. Spain. .......................................................................................... S. ibericus nov.sp.

- Ovipositor shorter, not more than 1.4× longer than fore wing. Tergites usually with yellow apical bands. ..........................................................................................................38

38. Claws strongly bent apically (by c. 90°). 1 st to 3 rd tergites black, red basally and apically, often with yellowish apical band (fig. 48). 4 th and 5 th tergites completely black. Hind femur red or brown. Antenna with 41-43 flagellomeres. 1 st tergite more than 2× longer than wide. Ovipositor sheath 1.1-1.2× longer than fore wing. Length 10- 12 mm. Europe. ..................................................................... S. szilagysagiensis KISS, 1926

- Claws moderately bent apically (less than 90°). Other characters different. .....................39

39. Ovipositor 1.4× longer than fore wing. MI 0.7. Antenna with 36-37 flagellomeres; flagellum dark brown or black. OED 1.4-1.6× ocellar diameter (fig. 128). 5 th tergite black. Turkey, Iran. .................................................................. S. paraturcator nov.sp., part

- Ovipositor shorter, at most 1.2× longer than fore wing.....................................................40

40. Hind coxa, trochanter and trochantellus mainly black. Ovipositor 1.0-1.15× as long as fore wing. 1 st tergite 1.6-1.7× longer than wide. Hind femur slender, 6.0-6.2× longer than wide. Apical tergites black. Length 10-12 mm. Spain. ......... S. ceballosi SEYRIG, 1926

- Hind coxa, trochanter AND/OR trochantellus ± yellow. 1 st tergite often slenderer. .........41

41. Ovipositor 0.9-1.2× as long as fore wing. Hind femur red. OED 1.1-1.4× ocellar diameter.............................................................................................................................42

- Ovipositor 0.7-0.85× as long as fore wing. Hind femur often brown or black. OED at most 1.2× ocellar diameter. ...............................................................................................44

42. Apical tergites black, 5 th tergite with yellow apical band. 2 nd tergite 1.1× longer than wide. OED 1.4× ocellar diameter (fig. 112). Hind femur red, 5.5× longer than wide. Length 10.5 mm. Mongolia.......................................................... S. flavomaculatus nov.sp.

- Apical tergites red or black, 5 th tergite without apical yellow band. Hind femur slenderer. ...........................................................................................................................43

43. OED 1.1× ocellar diameter (fig. 131). 5 th to 7 th tergites reddish. Hind femur 6.3× longer than wide. 1 st tergite 2.0-2.1× longer than wide, 2 nd tergite 1.3× longer than wide. Length 10.5 mm. Iran. ................................................................. S. pseudoceballosi nov.sp.

- OED 1.4× ocellar diameter (fig. 138). 5 th to 7 th tergites blackish, sometimes reddish laterally. Hind femur 5.7-6.0× longer than wide. 1 st tergite 1.8-1.9× longer than wide, 2 nd tergite 1.1-1.2× longer than wide. Length 8-10 mm. Near East. ...................................... ..................................................................................................... S. turcator AUBERT, 1984

44. Basal tergites very slender: 1 st tergite 2.6× and 2 nd tergite 1.5× longer than wide (fig. 42). Metasoma reddish-brown, 1 st to 4 th tergites with diffuse narrow yellowish apical bands. Antenna with 39 flagellomeres. Fore wing with strong brown apical spot. Malar space narrow, MI 0.5. Length 10 mm. Morocco. .............................. S. maroccanus nov.sp.

- Basal tergites stouter: 1 st tergite 2.0-2.2× and 2 nd tergite 1.1-1.2× longer than wide. 1 st to 4 th /5 th tergites with wide apical yellow bands................................................................45

45. OED 1.7× ocellar diameter (fig. 129). Pale coloration ivory (fig. 20). 5 th tergite black, without apical yellow band. Hind femur black. Antenna black. MI 0.4. Antenna with 36 flagellomeres. Fore wing with brown apical spot. Length 9 mm. Iran. ......... S. persicus nov.sp.

- OED at most 1.2× ocellar diameter. Pale coloration yellow. 5 th tergite with apical yellow band. ......................................................................................................................46

46. MI 0.4-0.5. Ocelli large, OED 0.9-1.0× ocellar diameter (fig. 120). Antenna ± reddish. Hind femur black or red. Antenna with 37-40 flagellomeres. Length 8.5-10.5 mm. Near East and Central Asia. ............................................................ S. kasparyator AUBERT, 1977

- MI 0.65-0.7. Ocelli smaller, OED at least 1.1× ocellar diameter. .....................................47

47. Basal tergites black, apical tergites reddish, 1 st to 4 th /5 th tergites with apical yellow bands. Antenna with 38-40 flagellomeres. Fore wing with apical brown spot. Length 9.5-10 mm. Spain. .......................................................................... S. dusmeti SEYRIG, 1928

- Tergites mainly red, 1 st to 5 th tergites with wide yellow apical bands. Antenna with 34- 37 flagellomeres. Fore wing hyaline. Length 9 mm. Morocco, Russia, Turkey. ................... .................................................................................................... S. robustor AUBERT, 1978