Key to Afrotropical Strumigenys

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This worker key is based on: Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028, updated with Rigato, F. 2006. Two new Strumigenys from Ethiopia. Atti della Società Italiana di Scienze Naturali 147: 103-111

Bolton noted - Three species (Strumigenys adrasora, Strumigenys helytruga, Strumigenys rukha) may be ambiguously keyed at couplet 1, either because the preocular notch is very small or the species shows some variation in development of the character. For convenience these species are keyed through each lug of the couplet.

This key is from a revision that included the now synonymized genus Pyramica. Therefore there are two keys that treat two sets of Strumigenys species, the key found below and a key to Afrotropical Pyramica.

You may also be interested in Strumigenys

1

  • Preocular notch present: ventrolateral margin of the head, and sometimes also side of head, impressed to deeply indented immediately in front of the eye, the indentation varying from a feeble impression in the ventrolateral margin to a notch so deep that the anterior portion of the eye is detached from the side of the head . . . . . 1-a
  • Preocular notch absent: ventrolateral margin of the head continuous to the anterior margin of the eye, without trace of an impression or indentation of the ventrolateral margin immediately in front of the eye . . . . . 23

1-a

return to couplet #1

Strumigenys alessandrae casent0900637 p 1 high.jpg

2

return to couplet #1-a

In Strumigenys cacaoensis apical tooth is very small, and preapical can be extremely small. Easily identifiable by its notched scrobe above the eye (K. Gómez)

2-a

return to couplet #2

  • Leading edge of scape with 2-4 hairs that are curved toward the base . . . . . 3
  • Leading edge of scape with all hairs curved or inclined toward the apex of the scape . . . . . 4

3

return to couplet #2-a

  • Size larger (TL 3.5-4.2). Pronotal humeral hair straight, stiff and stout, remiform to feebly clavate. Propodeum unarmed . . . . . Strumigenys londianensis
Strumigenys londianensis casent0900593 p 1 high.jpg
  • Size smaller (TL 2.4). Pronotal humeral hair fine and flagellate. Propodeum distinctly toothed Strumigenys bartolozzii
Rigato 2006-8 Strumigenys-bartolozzii hal.jpg

4

return to couplet #2-a

  • Cephalic dorsum with 6 short erect simple hairs: a transverse row of 4 close to occipital margin and a pair close to highest point of vertex. Apical fork of left mandible without an intercalary small tooth or denticle between the spiniform fork teeth. Smaller species with longer mandibles, HW 0.36-0.41, MI 55-65. (Cameroun, Equatorial Guinea, Gabon, Zaire, Angola) . . . . . . Strumigenys bernardi
Strumigenys bernardi casent0217946 p 1 high.jpg
  • Cephalic dorsum without erect simple hairs. Apical fork of left mandible with an intercalary small tooth or denticle between the spiniform fork teeth. Larger species with shorter mandibles, HW 0.50 - > 0.70, MI 51-55 . . . . . 5

5

return to couplet #4

  • Large species, HL 1.00 or more; maximum length of hind femur > 0.80. Anterior pronotal margin without a pair of hairs between the flagellate humeral hairs. Ventral carina of petiole expanded anteriorly into a broadly triangular obtuse lobe. (Burundi) . . . . . Strumigenys transenna
Strumigenys transenna casent0900595 p 1 high.jpg
  • Smaller species, HL < 1.00; maximum length of hind femur < 0.65. Anterior pronotal margin with a pair of erect stouter hairs between the humeral flagellate hairs. Ventral carina of petiole not expanded anteriorly into a broadly triangular obtuse lobe. (Zaire, Rwanda, Burundi, Uganda, Ethiopia) . . . . . Strumigenys sarissa
Strumigenys sarissa casent0102626 profile 1.jpg

6

return to couplet #2

  • Preocular notch on each side continued onto ventral surface of head as a transverse impression or groove of varying length, which extends toward but does not reach the midline; this preocular impression situated posterior to the postbuccal groove or impression and independent of it . . . . . 7
  • Preocular notch on each side not continued onto ventral surface of head, the ventral surface convex and, except for the notch in the ventrolateral margin, without transverse preocular impressions that extend toward the midline posterior to the postbuccal groove or impression . . . . . 16

7

return to couplet #6

  • Apical fork of left mandible with a strong intercalary tooth and also a smaller denticle between the spiniform fork teeth. Cephalic dorsum without standing hairs close to occipital margin. With head in full-face view the upper scrobe margin strongly notched above the eye. Large species, HW > 0.60. Preapical teeth about equal in size or the distal somewhat larger than the proximal. (Ghana, Nigeria, Gabon) . . . . . Strumigenys cacaoensis
Strumigenys cacaoensis casent0178324 profile 1.jpg
  • Apical fork of left mandible without trace of any intercalary tooth or denticle between the spiniform fork teeth. Cephalic dorsum with 2-4 standing hairs close to occipital margin. With head in full-face view the upper scrobe margin continuous above the eye. Smaller species, HW < 0.60. Preapical teeth with the distal shorter than the proximal . . . . . 8

8

return to couplet #7

9

return to couplet #8

  • Mandibles in full-face view and at full closure more or less straight, not conspicuously bowed outwards. On left mandible the distal preapical tooth about half the length of the proximal or slightly more, but stout and distinctly dentiform. Larger species, HW 0.42-0.52. (Cosmopolitan tramp species; very widespread in Afrotropical region, occurring as introduction in glasshouses etc. in Palaearctic) . . . . . Strumigenys rogeri
Strumigenys rogeri casent0005897 profile 1.jpg
  • Mandibles in full-face view and at full closure conspicuously bowed outwards. On left mandible the distal preapical tooth much less than half the length of the proximal, sometimes reduced to a mere denticle, not stout. Smaller species, HW 0.36-0.41 . . . . . 10

10

return to couplet #9

  • Dorsum of propodeum densely reticulate-punctate and dull. (Cameroun, Equatorial Guinea, Gabon, Zaire, Angola) . . . . . Strumigenys bernardi
Strumigenys bernardi casent0217946 p 1 high.jpg
  • Dorsum of propodeum smooth and shining. (Ivory Coast, Ghana, Nigeria) . . . . . Strumigenys vazerka
Strumigenys vazerka casent0102621 profile 1.jpg

11

return to couplet #8

12

return to couplet #11

  • Eye very large, its maximum diameter nearly twice the maximum width of the scape. Cephalic dorsum without a pair of simple standing hairs just in front of highest point of vertex. In profile ventral spongiform appendage of petiole a deep curtain, almost as deep as peduncle at its midlength. (Botswana, South Africa) . . . . . Strumigenys pretoriae
Strumigenys pretoriae casent0249038 p 1 high.jpg
  • Eye smaller, its maximum diameter subequal to the maximum width of the scape. Cephalic dorsum with a pair of simple standing hairs just in front of highest point of vertex. In profile ventral spongiform appendage of petiole a narrow crest, less than half as deep as peduncle at its midlength. (Guinea, Ivory Coast, Ghana, Nigeria, Cameroun, Gabon, Zaire, Angola, Sudan, Central African Republic) . . . . . Strumigenys petiolata
Strumigenys petiolata casent0102584 profile 1.jpg

13

return to couplet #11

  • Maximum diameter of eye equal to or only fractionally greater than the maximum width of the scape. Distal preapical tooth of left mandible short, separated from the proximal by a distance which is at least equal to the length of the distal tooth but which is sometimes more . . . . . 14
  • Maximum diameter of eye distinctly greater than the maximum width of the scape. Distal preapical tooth of left mandible long, separated from the proximal by a distance which is distinctly less than the length of the distal tooth . . . . . 15

14

return to couplet #13

  • Disc of postpetiole (when clean) usually very finely longitudinally superficially sculptured, only rarely smooth. With head in ventral view preocular impression broad and shallow, with poorly defined margins. (South Africa, Tanzania) . . . . . Strumigenys faurei
MCZ ENT Strumigenys faurei hal.jpg
  • Disc of postpetiole (when clean) usually smooth and shining, only rarely with traces of superficial sculpture. With head in ventral view preocular impression narrow, with sharply defined margins. (Guinea, Ivory Coast, Ghana, Togo, Nigeria) . . . . . Strumigenys rufobrunea
Strumigenys rufobrunea casent0280725 p 1 high.jpg

15

return to couplet #13

  • Preocular impression on ventral surface of head forming a parallel-sided groove that is narrower than the maximum diameter of the eye; the edges of the groove sharply defined. (Zimbabwe) . . . . . Strumigenys shaula
Strumigenys shaula casent0235721 p 1 high.jpg
  • Preocular impression on ventral surface of head forming a broad dish-like concavity that is at least as broad as the maximum diameter of the eye and usually broader; the edges of the impression are rounded and not sharply defined. (Burundi, Zaire, Tanzania) . . . . . Strumigenys dromoshaula
MCZ-ENT 34911 Holotype Strumigenys dromoshaula hal.jpg

16

return to couplet #6

  • Eye small, with only 8 ommatidia in total. Cephalic dorsum with only a single pair of standing hairs, close to midline near occipital margin. (Angola) . . . . . Strumigenys helytruga
Strumigenys helytruga casent0900619 p 1 high.jpg
  • Eye with more than 8 ommatidia in total. Cephalic dorsum with 4 or 6 standing hairs . . . . . 17

17

return to couplet #16

Strumigenys totyla casent0280726 p 1 high.jpg

18

return to couplet #17

  • In full-face view projecting hairs on leading edge of scape large and broadly spoon-shaped, about equal in size to the large broadly spoon-shaped hairs that fringe the upper scrobe margin. Cephalic dorsum with 4 stoutly remiform erect hairs, in a transverse row close to occipital margin; without a pair near highest point of vertex. Upper scrobe margin with a broad lamellate rim or flange. (Cameroun, Zaire) . . . . . Strumigenys xenohyla
Strumigenys xenohyla casent0900602 p 1 high.jpg
  • In full-face view projecting hairs on leading edge of scape slender, either distinctly narrower than those that fringe the upper scrobe margin or with hairs in both places conspicuously slender, spatulate to narrowly elongate spoon-shaped. Cephalic dorsum with 6 short simple erect hairs, a transverse row of 4 close to occipital margin and a pair near highest point of vertex. Upper scrobe margin with a narrow cariniform rim or flange . . . . . 19

19

return to couplet #18

  • With head in full-face view the closed mandibles not bowed outwards; greatest distance across mandibles is close to base. In same view each mandible gradually increases in width from level of proximal preapical tooth to close to base; outer margin of mandible abruptly inflected at extreme base. (Tanzania) . . . . . Strumigenys percrypta
Strumigenys percrypta casent0235717 p 1 high.jpg
  • With head in full-face view the closed mandibles bowed outwards; greatest distance across mandibles is at or distal of the midlength. In same view each mandible approximately the same width from level of proximal preapical tooth to close to base, or gradually narrows basally; outer margin of mandible not abruptly inflected at extreme base . . . . . 20

20

return to couplet #19

  • In profile the area of the ventral postpetiolar spongiform lobe conspicuously much less than the visible area of the disc. Lamella on declivity of propodeum very narrow or vestigial, the tooth free or nearly free of the lamella. Ventral appendage of petiole reduced to a narrow non-spongiform cuticular carina. (Zaire, Rwanda, Burundi, Uganda) . . . . . Strumigenys adrasora
Strumigenys adrasora casent0102628 profile 1.jpg
  • In profile the area of the ventral postpetiolar spongiform lobe equaling or exceeding the visible area of the disc. Lamella on declivity of propodeum broad, engaging half or more of the length of the tooth. Ventral appendage of petiole a spongiform strip or curtain . . . . . 21

21

return to couplet #20

  • With postpetiole in dorsal view spongiform material is visible projecting laterally at and in front of the midlength of the side of the disc. (Uganda, Kenya) . . . . . Strumigenys rukha
Strumigenys rukha casent0102151 profile 1.jpg
  • With postpetiole in dorsal view projecting spongiform material is restricted to the apices of the posterior transverse collar and does not occur in front of the midlength of the side of the disc . . . . . 22

22

return to couplet #21

  • Distal preapical tooth on left mandible greater than half the length of the proximal; length of the latter usually less than the distance separating it from the apicodorsal tooth, at most the two subequal. Scape shorter, SI 65-69. Occipital margin broadly and shallowly impressed. (Cameroun, Zaire, Angola) . . . . . Strumigenys relahyla
Strumigenys relahyla casent0900604 p 1 high.jpg
  • Distal preapical tooth on left mandible less than half the length of the proximal; the latter spiniform and its length distinctly greater than the distance separating it from the apicodorsal tooth. Scape longer, SI 70-74. Occipital margin narrowly and deeply impressed. (Zimbabwe) . . . . . Strumigenys dyshaula
Strumigenys dyshaula casent0102647 profile 1.jpg

23

return to couplet #1

  • Antenna with 4 segments, the first funicular segment followed directly by the 2-segmented club. Clypeus anteriorly very broad, in full-face view width across anterolateral angles is greater than SL. With head in full-face view the dorsolateral margin with a short stiff apicoscrobal hair. (Pan tropical tramp species) . . . . . Strumigenys emmae
Strumigenys emmae casent0005894 profile 1.jpg
  • Antenna with 5 or 6 segments, the first funicular segment separated from the 2- segmented club by one or two much smaller segments. Clypeus anteriorly narrow, in full-face view width across anterolateral angles is much less than SL. With head in full-face view the dorsolateral margin without an apicoscrobal hair . . . . . 24

24

return to couplet #23

25

return to couplet #24

Strumigenys irrorata casent0280727 p 1 high.jpg

26

return to couplet #25

  • Apical fork of left mandible with an intercalary denticle between the spiniform teeth. Dorsum of head without a transverse row of 4 standing hairs close to the occipital margin. (Zaire, Burundi, Uganda, Kenya) . . . . . Strumigenys katapelta
Strumigenys katapelta casent0900629 p 1 high.jpg
  • Apical fork of left mandible without an intercalary denticle between the spiniform teeth. Dorsum of head with a transverse row of 4 standing hairs close to the occipital margin and with an erect pair situated close to the highest point of the vertex . . . . . 27

27

return to couplet #26

  • Pronotal humeral hair straight, stout and thickly clavate. (Cameroun, Gabon) . . . . . Strumigenys paranax
Strumigenys paranax casent0900627 p 1 high.jpg
  • Pronotal humeral hair flagellate, long and fine . . . . . 28

28

return to couplet #27

  • With head in full-face view the mandible of approximately equal width from the proximal preapical tooth to near the extreme base. In same view upper scrobe margins shallowly convex, evenly divergent posteriorly; CI 71-77. Cephalic ground-pilosity on vertex behind level of frontal lobes narrowly spatulate, inconspicuous, narrower than hairs that fringe upper scrobe margin. (Cameroun, Equatorial Guinea, Gabon, Zaire, Angola, Central African Republic, Uganda) . . . . . Strumigenys dextra
Strumigenys dextra casent0900628 p 1 high.jpg
  • With head in full-face view the mandible increasing in width from the proximal preapical tooth to near the extreme base. In same view upper scrobe margins strongly convex, flaring posteriorly; CI 84. Cephalic ground-pilosity on vertex behind level of frontal lobes spoon-shaped, conspicuous, broader than hairs that fringe upper scrobe margin. (South Africa) . . . . . Strumigenys rakkota

29

return to couplet #24

  • Katepisternum sculptured, reticulate to reticulate-punctate; metapleuron and side of propodeum also extensively to entirely sculptured . . . . . 30
  • Katepisternum mostly to entirely smooth; metapleuron and side of propodeum usually with extensive smooth patches, only very rarely entirely sculptured . . . . . 32

30

return to couplet #29

  • Apicoventral tooth of fork of left mandible subtended by a minute denticle and a ventrobasal adventitious tooth that is about half the length of the apicoventral tooth. Disc of postpetiole smooth. Scape shorter, SI 57-63 . . . . . 31
  • Apicoventral tooth of fork of left mandible without additional teeth arising from its ventrobasal surface or at most with an extremely minute denticle-like point at the extreme base. Disc of postpetiole finely reticulate-punctate. Scape longer, SI 79. (Tanzania) . . . . . Strumigenys didyma

31

return to couplet #30

  • Pronotal humeral hair present, stout and straight, directed laterally and clavate apically. Dorsolateral margin of promesonotum with a row of 4-5 short clavate standing hairs. Dorsum of petiole node weakly transversely striate. (Ghana, Nigeria) . . . . . Strumigenys pallestes
Strumigenys pallestes casent0900623 p 1 high.jpg
  • Pronotal humeral hair absent. Dorsolateral margin of promesonotum without standing hairs. Dorsum of petiole node punctate. (South Africa) . . . . . Strumigenys marleyi

32

return to couplet #29

33

return to couplet #32

  • Leading edge of scape grossly expanded into a striking and very conspicuous anteriorly projecting lobe; maximum diameter of scape 0.50 X ML or more. (Uganda, Cameroun, Gabon) . . . . . Strumigenys tetraphanes
Strumigenys tetraphanes casent0178327 profile 1.jpg
  • Leading edge of scape not expanded into a gross projecting lobe; maximum diameter of scape less than 0.50 X ML . . . . . 34

34

return to couplet #33

  • Scape broadest proximal of the midlength, thereafter evenly tapering to the apex. Mandible in full-face view broader at level of proximal preapical tooth than at base. Mandibles and scape longer, head narrower, MI 48-50, SI 82-85, CI 67-71. (Ghana, Cameroun, Gabon) . . . . . Strumigenys korahyla
Strumigenys korahyla casent0900625 p 1 high.jpg
  • Scape broadest at or just distal of the midlength, narrowing both proximally and distally. Mandible in full-face view narrower at level of proximal preapical tooth than at base. Mandibles and scape shorter, head broader, MI 35-41, SI 54-75, CI 74-90 . . . . . 35

35

return to couplet #34

  • Larger species with relatively broad head and short scape, HW 0.62-0.69, CI 85-90, SI 54-59. (Gabon) . . . . . Strumigenys ultromalyx
Strumigenys ultromalyx casent0005657 profile 1.jpg
  • Smaller species with relatively narrow head and longer scape, HW 0.39-0.46, CI 74-80, SI 65-75 . . . . . 36

36

return to couplet #35

  • Disc of postpetiole completely unsculptured, smooth and shining. Pronotal dorsum finely reticulate-punctate and with longitudinal rugulae that overlie the punctate component. (Kenya, Zimbabwe) . . . . . Strumigenys arnoldi
Strumigenys arnoldi casent0235715 p 1 high.jpg
  • Disc of postpetiole longitudinally striolate to punctate-striolate, this sculpture usually denser toward sides of disc than at its centre. Pronotal dorsum finely reticulate-punctate, without overlying longitudinal rugulae. (Kenya, Tanzania) . . . . . Strumigenys omalyx
Strumigenys omalyx casent0102570 profile 1.jpg

37

return to couplet #32

  • Funicular segments 2 and 3 vestigial and difficult to see, partially or entirely fused together and partially fused to segment 4, so that the funiculus appears to have only 3 segments in total. Combined length of funicular segments 2 and 3 less than half the length of segment 4 (the penultimate segment) . . . . . 38
  • Funicular segments 2 and 3 small but easily visible, not fused together nor fused to segment 4, the funiculus distinctly with 5 segments. Combined length of funicular segments 2 and 3 more than half the length of segment 4 (the penultimate segment) . . . . . 39

38

return to couplet #37

  • Width of lamellate flange that borders upper scrobe margin distinctly greater than the maximum diameter of the eye, approaching the maximum width of the scape. Petiole node in dorsal view as broad as long. (Cameroun, Zaire) . . . . . Strumigenys bitheria
Strumigenys bitheria casent0900635 p 1 high.jpg
  • Width of lamellate flange that borders upper scrobe margin distinctly less than the maximum diameter of the eye, only a fraction of the maximum width of the scape. Petiole node in dorsal view much broader than long. (Ivory Coast, Ghana, Gabon) . . . . . Strumigenys nimbrata
Strumigenys nimbrata casent0102150 profile 1.jpg

39

return to couplet #37

  • Disc of postpetiole mostly or entirely sculptured . . . . . 40
  • Disc of postpetiole entirely smooth and shining (when clean, frequently with a waxy bloom present) . . . . . 42

40

return to couplet #39

  • Metapleuron and side of propodeum reticulate-punctate; on side of alitrunk only katepisternum smooth. Basigastral costulae extend over half the length of the first gastral tergite, spaces between costulae shagreenate. First gastral tergite with dense appressed long pubescence between the erect simple hairs. SI 88. (Sao Tome & Principe) . . . . . Strumigenys cenagra
Strumigenys cenagra casent0900622 p 1 high.jpg
  • Metapleuron and side of propodeum with extensive smooth areas; on side of alitrunk not only katepisternum smooth. Basigastral costulae shorter than half the length of the first gastral tergite, spaces between costulae smooth. First gastral tergite without dense appressed long pubescence between the erect simple hairs. SI 63-77 . . . . . 41

41

return to couplet #40

  • Ground-pilosity of cephalic dorsum, upper scrobe margin and leading edge of scape of narrow spatulate hairs. Scape slender and cylindrical, the leading edge not expanded and convex. MI 48, SI 77, CI 76. (Rwanda) . . . . . Strumigenys murshila
Strumigenys murshila casent0102568 profile 1.jpg
  • Ground-pilosity of cephalic dorsum, upper scrobe margin and leading edge of scape of broadly spoon-shaped or scale-like to suborbicular hairs. Scape flattened, the leading edge expanded and convex. MI 36-40, SI 63-68, CI 80-84. (Kenya, Zimbabwe, Cameroun, Angola) . . . . . Strumigenys stygia
Strumigenys stygia casent0280728 p 1 high.jpg

42

return to couplet #39

  • Maximum diameter of eye very obviously less than maximum width of scape. Eye usually with 3-6 ommatidia in total, only rarely with 7 or 8 in which case the scape is not extremely slender . . . . . 43
  • Maximum diameter of eye at least equal to and usually somewhat greater than maximum width of scape. Eye usually with more than 10 ommatidia in total but if only 7-8 present then scape is extremely slender . . . . . 48

43

return to couplet #42

  • Mandibles and scape very short, MI 26-30, SI 55-61. Scape flattened and expanded, only 3.1-3.3 X longer than broad, the leading edge strongly convex, prominent and lobate. (Ivory Coast, Ghana, Togo, Cameroun) . . . . . Strumigenys spathoda
Strumigenys spathoda casent0102618 profile 1.jpg
  • Mandibles and scape longer, MI 40-58, SI 70-90. Scape slender, 5.5-7.2 X longer than broad, the leading edge straight to weakly convex, not prominent nor lobate . . . . . 44

44

return to couplet #43

  • Scape longer, SI 80-90. Left mandible with distal preapical tooth at least half the length of the proximal tooth, and usually distinctly more. Proximal preapical tooth set somewhat farther from apex; in full-face view distance from clypeal margin to midbase of proximal tooth on left mandible is 1.5-2.0 X distance from midbase of proximal tooth to outer curve of apicodorsal tooth . . . . . 45
  • Scape shorter, SI 70-77. Left mandible with distal preapical tooth distinctly less than half the length of the proximal tooth. Proximal preapical tooth set somewhat closer to apex; in full-face view distance from clypeal margin to midbase of proximal tooth on left mandible is 2.5-3.0 X distance from midbase of proximal tooth to outer curve of apicodorsal tooth . . . . . 46

45

return to couplet #44

  • Distal preapical tooth slightly longer than proximal. Mandibles relatively long, MI 58. Postpetiole not swollen, not subglobular. Outline of pronotal dorsum forming an inverted V-shape in anterior view. (Uganda) . . . . . Strumigenys semicrypta
Strumigenys semicrypta casent0900626 p 1 high.jpg
  • Distal preapical tooth shorter than proximal. Mandibles shorter, MI 45-50. Postpetiole swollen and subglobular. Outline of pronotal dorsum evenly convex in anterior view. (South Africa) . . . . . Strumigenys havilandi
Strumigenys havilandi casent0249003 p 1 high.jpg

46

return to couplet #44

  • Dorsum of head with 4 standing hairs. Cephalic ground-pilosity spoon-shaped to scale-like everywhere, not much narrower on the posterior half of the head. Hairs fringing upper scrobe margin broad and spoon-shaped. Hairs on first gastral tergite sparse, long and flattened, long-remiform to strap-like. (Zimbabwe) . . . . . Strumigenys mesahyla
Strumigenys mesahyla casent0900632 p 1 high.jpg
  • Dorsum of head with 6 standing hairs. Cephalic ground-pilosity much narrower on the posterior half of the head than on the anterior half, the latter spatulate. Hairs fringing upper scrobe margin spatulate. Hairs on first gastral tergite numerous, simple or slightly flattened or thickened apically . . . . . 47

47

return to couplet #46

  • Mesonotum with 2 or 3 (rarely 4) pairs of erect hairs. Head in profile somewhat deeper and with more convex dorsal and ventral outlines; head capsule 1.62-1.65 X longer than its maximum depth. (South Africa) . . . . . Strumigenys traegaordhi
Strumigenys traegaordhi casent0280729 p 1 high.jpg
  • Mesonotum with a single pair of erect hairs. Head in profile somewhat shallower and with less convex dorsal and ventral outlines; head capsule 1.77-1.80 X longer than its maximum depth. (South Africa) . . . . . Strumigenys syntacta
Strumigenys syntacta casent0900633 p 1 high.jpg

48

return to couplet #42

  • Petiole in profile without a ventral spongiform strip or curtain beneath the peduncle. Ventral spongiform lobe of postpetiole in profile small, distinctly smaller than the exposed area of the postpetiole disc. (Zaire, Rwanda, Burundi, Uganda) . . . . . Strumigenys adrasora
Strumigenys adrasora casent0102628 profile 1.jpg
  • Petiole in profile with a ventral spongiform strip or curtain beneath the peduncle. Ventral spongiform lobe of postpetiole in profile larger, at least as large as the exposed area of the postpetiole disc . . . . . 49

49

return to couplet #48

  • With head in full-face view the hairs that fringe the upper scrobe margin distinctly much larger than the minute hairs of the cephalic ground-pilosity. Mandibles markedly bowed outwards, outer margin strongly convex between proximal preapical tooth and base . . . . . 50
  • With head in full-face view the hairs that fringe the upper scrobe margin the same size as the hairs of the cephalic ground-pilosity. Mandibles not strongly bowed outwards, outer margin straight to only slightly convex between proximal preapical tooth and base . . . . . 51

50

return to couplet #49

  • Yellow species with longer mandibles and scape, MI 47-49, SI 67-73. (Uganda, Kenya) . . . . . Strumigenys rukha
Strumigenys rukha casent0102151 profile 1.jpg
  • Blackish brown species with shorter mandibles and scape, MI 40-43, SI 59-62. (Cameroun, Gabon) . . . . . Strumigenys ettillax
Strumigenys ettillax casent0900603 p 1 high.jpg

51

return to couplet #49

  • Hairs on first gastral tergite slender and simple, of constant diameter throughout their lengths and pointed apically; gastral hairs never remiform, nor expanded apically nor flattened apically . . . . . 52
  • Hairs on first gastral tergite not slender and simple; either stout, or diameter increasing toward apex, or remiform, or somewhat expanded or flattened apically . . . . . 53

52

return to couplet #51

  • Scape longer, SI 89-95. Petiole node in dorsal view as long as broad, or slightly longer than broad. (Sao Tome & Principe) . . . . . Strumigenys sibyna
Strumigenys sibyna castype17579 profile 1.jpg
  • Scape shorter, SI 75-81. Petiole node i n dorsal view distinctly broader than long. (Annobon I., Cameroun) . . . . . Strumigenys zandala
Strumigenys zandala casent0102149 profile 1.jpg

53

return to couplet #51

  • Distal preapical tooth of left mandible very reduced, less than half the length of the proximal tooth and much narrower. Dark brown to blackish-brown species with relatively broad head, CI 79-81. (South Africa) . . . . . Strumigenys syntacta
Strumigenys syntacta casent0900633 p 1 high.jpg
  • Distal preapical tooth of left mandible stout, more than half the length of the proximal tooth and not much narrower. Dull yellow to brownish-yellow species with relatively narrow head, CI 73-75 . . . . . 54

54

return to couplet #53

  • Cephalic dorsum with a pair of erect short hairs near highest point of vertex, and with 4 similar hairs in a transverse row near the occipital margin. Maximum diameter of eye greater than maximum width of slender scape. Outer margins of mandibles shallowly convex. Smaller species, HL 0.49-0.52. (Ivory Coast, Nigeria, Cameroun, Gabon, Zaire, Burundi, Angola) . . . . . Strumigenys hastyla
Strumigenys hastyla casent0900620 p 1 high.jpg
  • Cephalic dorsum without erect short hairs near highest point of vertex, any such hairs restricted to near the occipital margin. Maximum diameter of eye about the same as maximum width of slender scape. Outer margins of mandibles more or less straight. Larger species, HL 0.59. (Angola) . . . . . Strumigenys helytruga
Strumigenys helytruga casent0900619 p 1 high.jpg