Orthocentrus, Gravenhorst, 1829

Humala, Andrei E., 2019, Mexican species of the genus Orthocentrus (Hymenoptera, Ichneumonidae: Orthocentrinae), Zootaxa 4709 (1), pp. 1-83 : 6-9

Key to the Mexican species of Orthocentrus

1 Antennal sockets on a high protruding shelf and antenna thick and usually somewhat curled (at least in dried specimens), basal flagellomeres transverse-quadrate ( Figs 2 , 3 A–C); face either completely polished and punctate or completely weakly matt/coriaceous-pustulate to coriaceous ( Figs 9 A–I) ( O. shieldsi species-group)......................................... 2

- Never with the above combination of characters; if antennal sockets on a protruding shelf, shelf lower and/or face papillatepustulate ( Figs 12 A–K); basal flagellomeres elongate....................................................... 12

2 Fore wing with areolet open ( Fig. 2D )..................................................................... 3

- Fore wing with areolet closed ( Figs 2 A–C, 2 F, 3 A–C)....................................................... 4

3 Eyes densely setose ( Fig. 9 E ); antenna with 24 flagellomeres.................................... lostuxtlasi sp. nov.

- Eyes glabrous; antenna with 33 flagellomeres................................................ kasparyani sp. nov.

4 Smaller species, fore wing length 2.3–2.4 mm; eyes small, malar space about 0.75 × as long as eye height; head posteriorly deeply concave.................................................................... microphthalmus sp. nov.

- Larger species, fore wing length 2.5–3.6 mm, never with the above combination of characters........................ 5

5 Eyes glabrous........................................................................................ 6

- Eyes setose.......................................................................................... 9

6 Areolet in fore wing relatively large, transverse, distinctly wider than high; vein 3rs-m well pigmented................. 7

- Areolet in fore wing about as wide as high, vein 3rs-m weakly pigmented........................................ 8

7 Head narrow, Hw/Fp = 2.5; face and dorso-posterior corner of pronotum fuscous; first and second tergites with weak and shallow furrows, polished posteriorly; antenna with 20–21 flagellomeres; areolet not particularly large....... pentagonum Broad

- Head wider, Hw/Fp = 3.0; face and dorso-posterior corner of pronotum mostly yellowish-orange; first and second tergites with deep and strong transverse furrows; antenna with 26–27 flagellomeres; areolet large................... areolatus sp. nov.

8 Head wide, Hw/Fp = 5.1; face fuscous with yellow triangular spots under antennal sockets, connected with yellow frontal orbits; clypeus yellowish; dorso-posterior corner of pronotum yellow; flagellum reddish-brown............ vulgaris sp. nov.

- Head narrow, Hw/Fp = 3.2; face and clypeus yellowish-orange; malar space convex; dorso-posterior corner of pronotum light brown; flagellum fuscous................................................................... ocampo sp. nov.

9 Eyes with long dense setae; face smoothly coriaceous-pustulate................................. hispidus Veijalainen

- Eyes with scarce and short setae; face finely horizontally strigose-pustulate or smooth and polished................... 10

10 Occiput deeply concave, face slightly prominent, Hw/Fp = 5.1 ( Fig. 13 I ); areolet in fore wing relatively large, distinctly wider than high; frontal orbits fuscous; face fuscous with light brown marks under antennal sockets............ zaldivari sp. nov.

- Occiput moderately concave, face prominent, Hw/Fp = 4.1–4.4 ( Figs 13 B, C ); areolet in fore wing nearly as wide as high; frontal orbits yellow up to front ocellus; face mostly orange or light brown....................................... 11

11 Mesosoma and hind coxa contrastingly coloured: dark brown dorso-laterally and yellowish ventrally; first tergite with strong dorsal carinae; face infuscate laterally; posterior ocelli distant from eye by ocellar diameter........... dorsofuscus sp. nov.

- Mesosoma fuscous; hind coxa black dorso-basally and yellowish ventro-apically; first tergite with weak dorsal carinae; face mostly yellowish-orange; posterior ocelli distant from eye by 1.5 × ocellar diameter.................... fuscipes sp. nov.

12 Antenna slender, distinctly longer than body, with 35–42 thin elongate flagellomeres; basal flagellomere 5.0–6.0 × as long as wide and at least as long as scape; second tergite heavily and completely strigose to strigose-rugose, sculpture usually extending onto anterior of third tergite. ( O. insularis species-group)..................................................... 13

- Antenna at most moderately long, shorter than body, with 19–35 flagellomeres; basal flagellomere 0.8–4.5 × as long as wide and as a rule shorter than scape; second tergite with various sculpture, not extending onto anterior of third tergite........ 14

13 Mesoscutum with white ‘shoulder-stripes’, originating antero-laterally and extending along notaular lines; tergites 1–3 (especially 2–3) with foveolate-rugose sculpture, strigose elements inconspicuous ( Fig. 18 L ); eyes distinctly setose ( Fig. 12 L )............................................................................................. ruizi sp. nov.

- Mesoscutum lacking ‘shoulder-stripes’, with diffuse paler brown stripes along notaular lines; tergites 1–3 (especially 2–3) with strong strigose-rugose sculpture; eyes with short inconspicuous setae................................ brevipilus Broad

14 Propodeum with posterior transverse carina complete; head lenticular, temples short, face glabrous; notauli present anteriorly (sometimes undeveloped).............................................................................. 15

- Propodeum with posterior transverse carina not present lateral of lateral longitudinal carinae (sometimes whole posterior transverse carina weak/absent); head with a low protruding shelf bearing antennal sockets; temples well developed; face completely papillate-pustulate; notauli present or missing.............................................................. 32

15 Areolet in fore wing absent ( O. maculae species-group)...................................................... 16

- Areolet in fore wing present ( O. montanus species-group).................................................... 27

16 Mesoscutum anteriorly without notauli; inner orbits light yellow to ocelli level, hind wing with nervellus (vein cu-a) intercepted at lower third, lateral longitudinal carinae of propodeum reduced anteriorly; subocular sulcus slightly bent... similis sp. nov.

- Never with the above combination of characters; mesoscutum anteriorly with short notauli.......................... 17

17 Tergites 3–5 with conspicuous median incisions apically ( Fig. 18 M )................................ tergalis sp. nov.

- Tergites lacking apical incisions......................................................................... 18

18 Hind coxa mostly black or dark brown, at least basally fuscous................................................ 19

- Hind coxa mostly yellow to orange (often with fuscous maculae dorsally or apically, but not fuscous basally)........... 23

19 Basal flagellomere about 4.0 × as long as wide; notauli undeveloped; scutellum very steeply convex; subocular sulcus slightly bent towards occiput; hind femur and tibia mostly fuscous....................................... scutellatus sp. nov.

- Basal flagellomere 1.5–2.0 × as long as wide.............................................................. 20

20 Subocular sulcus nearly straight; hind coxa dark brown............................................ lopezi sp. nov.

- Subocular sulcus strongly bent towards occiput ( Fig. 4 F ); hind coxa at most basally dark brown..................... 21

21 Antennae short, with 18–20 flagellomeres; ovipositor without dorsal notch; frons and malar space fuscous; nervellus intercepted at apical third................................................................. luteoclypeus Veijalainen

- Antennae longer, with 23 flagellomeres; ovipositor with a distinct dorsal notch; malar space and frontal orbits creamy white; nervellus not intercepted............................................................................... 22

22 Face light brown, orbits and malar space creamy white to bright yellow from antennal sockets to level of posterior ocelli; hind coxa brown except apex orange, hind femur and tibia orange, infuscate apically..................... maculae Veijalainen

- Face brown, creamy spots along frontal orbits not reach level of anterior ocelli; hind coxa entirely black, hind femur and tibia fuscous................................................................................... latus sp. nov.

23 Face slightly protruding, not forming a distinct shelf for antennal sockets; second tergite and third tergite anteriorly with pair of median longitudinal carinae ( Fig. 17 B ); antenna with 19 flagellomeres, basal flagellomere about 3.5 × as long as wide......................................................................................... coronadoae sp. nov.

- Face distinctly protruding and forming a high shelf for antennal sockets; median longitudinal carinae at most with short stubs on anterior of second tergite, third tergite lacking longitudinal carinae; antenna with more than 20 flagellomeres, basal flagellomere shorter, 1.8–3.0 × as long as wide................................................................. 24

24 Subocular sulcus strongly bent towards occiput............................................. brevicornis sp. nov.

- Subocular sulcus nearly straight......................................................................... 25

25 Mesopleuron yellowish brown, except for small fuscous area dorso-medially ( Fig. 5 B ); basal flagellomere 3.0 × as long as wide. Dorsal ridge of face inbetween antennal sockets without a median prominence.................. rufipleuris sp. nov.

- Mesopleuron mostly fuscous; basal flagellomere 1.8–2.3 × as long as wide. Dorsal ridge of face inbetween antennal sockets with a median prominence............................................................................. 26

26 Temples very narrow, 0.1 × as long as eye width; dorsal ridge of face inbetween antennal sockets with a median blunt low prominence; frontal orbits as a rule fuscous; first tergite 1.3 × as long as apically wide.................. varicolor sp. nov.

- Temples 0.25 × as long as eye width; dorsal ridge of face inbetween antennal sockets with a median prominence; frontal orbits creamy up to posterior ocelli; first tergite 1.7 × as long as apically wide............................. rectus Veijalainen

27 Head strongly transverse, frontal orbits with yellow marks not reaching level of anterior ocellus...................... 28

- Head slightly transverse, frontal orbits entirely yellow up to occiput............................................ 29

28 Antenna with 23 flagellomeres, first flagellomere 1.8 × as long as wide; face smooth, polished, sparsely punctate; subocular sulcus strongly bent towards occiput.......................................................... malaris sp. nov.

- Antenna with 28–29 flagellomeres, first flagellomere 3.0 × as long as wide; face horizontally strigose; subocular sulcus slightly bent towards occiput.................................................................... tlaxcalensis sp. nov.

29 Antenna with 26–27 flagellomeres, first flagellomere 2.1–2.3 × as long as wide..................... montezuma sp. nov.

- Antenna with 21–25 flagellomeres, first flagellomere 1.4–1.8 × as long as wide................................... 30

30 Pronotum with dorso-posterior corners yellow; antenna with 21–23 flagellomeres..................... khalaimi sp. nov.

- Pronotum with yellowish dorsal stripes along its upper side; antenna with 23–25 flagellomeres....................... 31

31 Mesoscutum and lower mesopleuron reddish brown; tergites 1–2 wider, its spiracles protruding ( Fig. 16 N ); second thyridia distinct; temple wider, 0.5 × eye width; occiput deeply concave...................................... sierrae sp. nov.

- Mesoscutum and mesopleuron blackish brown, tergites 1–2 slenderer, its spiracles not protruding ( Fig. 16 L ); second thyridia undeveloped; temple narrower, 0.35 × eye width; occiput moderately concave....................... montanus sp. nov.

32 Eyes densely setose ( O. wahlbergi species-group).......................................................... 33

- Eyes without conspicuous setae (at most with scarce short hairs)............................................... 37

33 Pterostigma strongly asymmetrical (radius meeting pterostigma at apical third)................................... 34

- Pterostigma nearly symmetrical......................................................................... 36

34 Basal flagellomere 1.2–1.3 × as long as wide.................................................... pictus sp. nov.

- Basal flagellomere longer, 2.0–4.1 × as long as wide........................................................ 35

35 Mesoscutum with contrastingly yellowish ‘shoulder-stripes’ originating antero-laterally and extending along notaular lines. Head slightly concave posteriorly, Hw/Fp = 4.7; eyes with scarce long setae. Basal flagellomere 2.0–2.5 × as long as wide; areolet closed, vein 3rs-m depigmented.................................................... wahlbergi Veijalainen

- Mesoscutum with ‘shoulder stripes’ diffuse and indistinct. Head strongly concave posteriorly, Hw/Fp = 7.1 ( Fig. 15 K ); eyes densely setose. Basal flagellomere about 4.0 × as long as wide; areolet open........................ veracruzus sp. nov.

36 Frons mainly fuscous; frontal orbits and ‘shoulder-stripes’ along notaular lines diffusely light brown; second tergite coriaceousstrigose with distinct transverse impressions, posterior ocellus separated from eye by 0.6 × ocellar diameter.. minor sp. nov.

- Frons creamy with fuscous interocellar area; ‘shoulder-stripes’ along notaular lines distinct, creamy or light yellow; second tergite smoothly coriaceous-strigose, transverse impressions superficial; posterior ocellus separated from eye by 1.0 × ocellar diameter........................................................................ nicaraguensis Veijalainen

37 Basal flagellomere 0.9–1.3 × as long as wide.............................................................. 38

- Basal flagellomere 1.8–4.5 × as long as wide.............................................................. 46

38 Fore wing with areolet open............................................................................ 39

- Fore wing with areolet closed........................................................................... 41

39 Frontal orbits yellow up to occiput ( Fig. 15 F ); antenna with 23 flagellomeres; hind femur 2.5 × as long as high; first tergite 1.7 × as long as apically wide................................................................... oaxacae sp. nov.

- Frontal orbits fuscous or with small yellowish spots close to antennal sockets; antenna with 24–27 flagellomeres; hind femur 2.9–3.0 × as long as high.............................................................................. 40

40 Nervellus not intercepted; second portion of cubitus as long as vein 2rs-m; eyes with short setae; first tergite 1.3–1.4 × as long as apically wide; basal flagellomere about 1.5 × as long as wide; yellow spots on frontal orbits at level of antennal sockets................................................................................... mexicanus sp. nov.

- Nervellus intercepted near the middle; second portion of cubitus 3 × as long as vein 2rs-m; eyes glabrous; first tergite 1.6 × as long as apically wide; basal flagellomere as long as wide; frontal orbits fuscous................... tamaulipecus sp. nov.

41 Antenna with 21–24 flagellomeres....................................................................... 42

- Antenna with 25–30 flagellomeres....................................................................... 43

42 Hind femur very stout, 2.5 × as long as high; face papillate-pustulate; female with lower frons yellow; second tergite entirely coriaceous............................................................................ podagricus sp. nov.

- Hind femur slenderer, 2.9 × as long as high; face polished, transversely striated; females with yellow or creamy frontal orbits, males with frons entirely yellow (creamy); second tergite coriaceous with latero-posterior corners polished..................................................................................................... sannio Holmgren

43 Pronotum entirely yellowish; antenna slender, with 26–29 flagellomeres; basal flagellomere transverse, 0.9 × as long as wide....................................................................................... collaris sp. nov.

- Pronotum mostly fuscous; antenna with 25–30 flagellomeres; basal flagellomere longer than wide.................... 44

44 Female frontal orbits without distinct yellow spots; second tergite slenderer, clearly longer than apically wide; areolet distinctly wider than high; nervellus intercepted below; males with frons fuscous and pterostigma strongly widened.. winnertzii Förster

- Frontal orbits with yellow spots; second tergite transverse or hardly longer than wide; fore wing with areolet narrowly sessile, shorter than high; nervellus not intercepted................................................................ 45

45 More stout species; second tergite transverse; hind femur stout, 2.5 × as long as high; hind legs yellowish. asper Gravenhorst

- Slenderer species; second tergite longer than apically wide; hind femur 3.1 × as long as high; hind coxa and femur mostly dark brown.................................................................................. aztecus sp. nov.

46 Metasoma comparatively short or moderately elongate; antenna moderately long, with 23–28 flagellomeres; hind claws not particularly large..................................................................................... 47

- Metasoma elongate; antenna long and slender, with 27–35 flagellomeres; hind claws enlarged ( O. ungularis species-group) 48

47 Fore wing without areolet; antenna with 23 flagellomeres; face horizontally strigose; head and mesoscutum finely punctured; upper frontal orbits yellow; eyes glabrous; metasoma distinctly longer than head and mesosoma together; second tergite with strong transverse furrow.................................................................. contrerasi sp. nov.

- Fore wing with areolet closed; antenna with 28 flagellomeres; face, frons and mesoscutum roughly punctured; upper frontal orbits fuscous; eyes with inconspicuous scarce and short setae; metasoma as long as head and mesosoma together; second tergite with shallow transverse subapical impression................................................. scabrosus sp. nov.

48 Basal flagellomere 3.5–4.5 × as long as wide, antenna with 29–31 flagellomeres; pterostigma asymmetrical (radius meeting pterostigma at apical 0.35)............................................................................. 49

- Basal flagellomere 1.8–2.7 × as long as wide; pterostigma nearly symmetrical (radius meeting pterostigma at the middle); fore wing with areolet large, conspicuously transverse, about twice as wide as high.................................... 50

49 Areolet open; temples extremely narrow, occiput slightly concave; second tergite with central rhombic area bounded by strong anterolateral diagonal impressions connected with angular posterior transverse groove ( Fig. 17 N )....... rhombifer sp. nov.

- Areolet closed, but vein 3rs-m faint and depigmented; temples distinct, occiput strongly concave; second tergite without central rhombic area ( Fig. 17 K ).............................................................. flavoorbitalis sp. nov.

50 Frontal orbits yellow up to occiput; mesoscutum with distinct yellow ‘shoulder-stripes’ originating antero-laterally and extending along notaular lines; antenna with 31–35 flagellomeres, basal flagellomere 1.8–2.1 × as long as wide............... 51

- Frontal with creamy marks not reaching ocellus level; mesoscutum fuscous; antenna with 27–29 flagellomeres, basal flagellomere 2.3–2.7 × as long as wide........................................................................ 52

51 First tergite 1.6 × as long as posteriorly wide, lacking transverse impressions and dorsal carinae; second tergite without oval uplifted median area, only posterior transverse groove developed; yellowish frontal orbits widely interrupted between face and vertex ( Fig. 14 O ), scutellum fuscous, mesopleuron mostly brown.................................. ungularis sp. nov.

- First tergite 2.5 × as long as posteriorly wide, with deep transverse impressions and distinct dorsal carinae; second tergite with nearly oval uplifted median area bordered by grooves; yellowish frontal orbits not interrupted between face and vertex; scutellum yellowish; mesopleuron mostly orange................................................. hidalgoensis sp. nov.

52 First tergite 2.1 × as long as posteriorly wide; face brown; dorsal ridge of face inbetween antennal sockets without a median prominence; subocular sulcus slightly bent towards occiput; hind legs mostly brown; hind femur slenderer, 3.3 × as long as maximum depth....................................................................... longiventris sp. nov.

- First tergite 1.3 × as long as posteriorly wide; face yellow; dorsal ridge of face inbetween antennal sockets with a median prominence; subocular sulcus straight; hind legs mostly yellow; hind femur stouter, 2.8 × as long as maximum depth............................................................................................ elongatus sp. nov.

Figures

FIGURE 2. Lateral views: Orthocentrus shieldsi species-group (in part). A: areolatus, B: dorsofuscus, C: fuscipes, D: kasparyani, E: lostuxtlasi, F: microphthalmus. Scale 1.0 mm.

FIGURE 3. Lateral views: Orthocentrus shieldsi (in part) and O. montanus (in part) species-groups.A: ocampo, B: vulgaris, C: zaldivari, D: khalaimi, E: malaris, F: montanus, Scale 1.0 mm.

FIGURE 4. Lateral views: Orthocentrus montanus (in part) and O. maculae (in part) species-groups.A: montezuma, B: sierrae, C: tlaxcalensis, D: brevicornis, E: coronadoae, F: latus. Scale 1.0 mm.

FIGURE 5. Lateral views: Orthocentrus maculae species-group.A: lopezi, B: rufipleuris, C: scutellatus, D: similis, E: tergalis, F: varicolor. Scale 1.0 mm.

FIGURE 9. Faces: Orthocentrus shieldsi and O. montanus (in part) species-groups. A: areolatus, B: dorsofuscus, C: fuscipes, D: kasparyani, E: lostuxtlasi, F: microphthalmus, G: ocampo, H: vulgaris, I: zaldivari, J: khalaimi, K: malaris, L: montanus. Scale 0.2 mm.

FIGURE 12. Faces: Orthocentrus wahlbergi and O. insularis species-groups. A: aztecus, B: collaris, C: contrerasi, D: mexicanus, E: minor, F: oaxacae, G: pictus, H: podagricus, I: scabrosus, J: tamaulipecus, K: veracruzus, L: ruizi. Scale 0.2 mm.

FIGURE 13. Heads in dorsal view: Orthocentrus shieldsi and O. montanus species-groups. A: areolatus, B: dorsofuscus, C: fuscipes, D: kasparyani, E: lostuxtlasi, F: microphthalmus, G: ocampo, H: vulgaris, I: zaldivari, J: khalaimi, K: malaris, L: montanus, M: montezuma, N: sierrae, O: tlaxcalensis. Scale 0.2 mm.

FIGURE 14. Heads in dorsal view: Orthocentrus maculae and O. ungularis species-groups. A: brevicornis, B: coronadoae, C: latus, D: lopezi, E: rufipleuris, F: scutellatus, G: similis, H: tergalis, I: varicolor, J: elongatus, K: flavoorbitalis, L: hidalgoensis, M: longiventris, N: rhombifer, O: ungularis. Scale 0.2 mm.

FIGURE 15. Heads in dorsal view: Orthocentrus wahlbergi and O. insularis species-groups. A: aztecus, B: collaris, C: contrerasi, D: mexicanus, E: minor, F: oaxacae, G: pictus, H: podagricus, I: scabrosus, J: tamaulipecus, K: veracruzus, L: ruizi. Scale 0.2 mm.

FIGURE 16. Basal tergites: Orthocentrus shieldsi and O. montanus species-groups. A: areolatus, B: dorsofuscus, C: fuscipes, D: kasparyani, E: lostuxtlasi, F: microphthalmus, G: ocampo, H: vulgaris, I: zaldivari, J: khalaimi, K: malaris, L: montanus, M: montezuma, N: sierrae, O: tlaxcalensis. Scale 0.2 mm.

FIGURE 17. Basal tergites: Orthocentrus maculae and O. ungularis species-groups. A: brevicornis, B: coronadoae, C: latus, D: lopezi, E: rufipleuris, F: scutellatus, G: similis, H: tergalis, I: varicolor, J: elongatus, K: flavoorbitalis, L: hidalgoensis, M: longiventris, N: rhombifer, O: ungularis. Scale 0.2 mm.

FIGURE 18. Basal tergites: Orthocentrus wahlbergi and O. insularis species-groups. A: aztecus, B: collaris, C: contrerasi, D: mexicanus, E: minor, F: oaxacae, G: pictus, H: podagricus, I: scabrosus, J: tamaulipecus, K: veracruzus, L: ruizi. Scale 0.2 mm. Metasoma dorso-lateral view: M: Orthocentrus tergalis. Scale 0.5 mm.