Key to Malagasy Leptogenys

This key to workers will also work for the known ergatoid queens. Key based on: Rakotonirina, J.C. & Fisher, B.L. 2014. Revision of the Malagasy ponerine ants of the genus Leptogenys Roger (Hymenoptera: Formicidae). Zootaxa 3836, 1-163. doi:10.11646/zootaxa.3836.1.1

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 * Leptogenys
 * Ants of Madagascar

1

 * In full-face view, mandible either subtriangular (Fig. 1A) or elongate (Fig. 1B, 1C) but capable of closing tightly against the anterior margin of clypeus without a gap between them . . . . . 2


 * In full-face view, mandible elongate and narrow, not capable of closing tightly against the clypeus; the apices slightly crossing each other and leaving a large gap between themselves and the clypeus when closed (Fig. 1D) . . . . . 40

2
return to couplet #1
 * With abdominal segment 3 (first gastral segment) in profile, prora generally globular and voluminous, directed anteroventrally; prora and the rounded anteroventral angle of third abdominal sternite usually separated by large indentation (Fig. 2A, 3D) . . . . . 3


 * With abdominal segment 3 (first gastral segment) in profile, prora flattened, small and directed ventrally in a vertical line; prora and anteroventral angle of third abdominal sternite not separated by large indentation, prora directly at anteroventral angle of third abdominal sternite (Fig. 2B, 2C) . . . . . 6

3
return to couplet #2
 * In full-face view head short (CI: 78–82) (Fig. 3A); in lateral view, petiolar node noticeably higher than long; prora immediately at anteroventral angle of third abdominal sternite (Fig. 3B) . . . . . Leptogenys avaratra


 * In full-face view, head more elongate (CI: 69–75) (Fig. 3C); in lateral view, petiolar node approximately as high as long; prora separated from the rounded anteroventral angle of third abdominal sternite (Fig. 3D) . . . . . 4

4
return to couplet #3
 * Antennal scape with erect hairs whose length is equal to the maximum width of the scape (Fig. 4A); propodeal declivity mostly smooth; in profile, dorsal face of petiolar node sloping posteriorly (Fig. 4B) . . . . . Leptogenys bezanozano


 * Antennal scape with erect hairs whose length is shorter than the maximum width of the scape (Fig. 4C); propodeal declivity transversely striate; in profile, dorsal face of petiolar node horizontal, not sloping (Fig. 4D) . . . . . 5

5
return to couplet #4
 * In full-face view, eye maximum diameter greater than the maximum width of antennal scape; dorsum of head coarsely sculptured, reticulate-rugulose to reticulate-punctate anteriorly and sparsely punctate posteriorly (Fig. 5A) . . . . . Leptogenys avo


 * In full-face view, eye maximum diameter much less than the maximum width of antennal scape; dorsum of head mostly with scattered punctures, which become sparser posteriorly (Fig. 5B) . . . . . Leptogenys toeraniva

6
return to couplet #2
 * In full-face view, greatest width of eye roughly equal to or less than the greatest width of antennal scape (Fig. 6A); smaller species (HW: 0.60–0.83, PW: 0.59–0.70) . . . . . 7


 * In full-face view, greatest width of eye markedly greater than the maximum width of antennal scape (Fig. 6B); generally larger species (HW: 0.75–1.92, PW: 0.60–1.62) . . . . . 10

7
return to couplet #6
 * Masticatory margin of mandible with three teeth, a median tooth between the sharp apical tooth and the blunt basal angle; in profile, subpetiolar process simple with only an anteroventral triangular lobe or blunt tooth, posterior lobe absent (Fig. 7A) . . . . . Leptogenys alamando


 * Masticatory margin of mandible with two teeth, a sharp apical tooth or lamella and a small, very short, preapical one or a blunt angle; in profile, subpetiolar process double, consisting of an anteroventral lobe or tubercle followed posteriorly by a thin cuticular extension or a lobe in the middle of the ventral margin (Fig. 7B, 7C) . . . . . 8

8
return to couplet #7
 * Mandibles longitudinally striate; piligerous punctures larger and more closely spaced on dorsum of head (Fig. 8A) and the rest of body; hairs on the dorsum of body abundant, short and subdecumbent or appressed . . . . . Leptogenys rabesoni


 * Mandibles smooth and shiny, with sparse piligerous punctures; dorsum of head and rest of body generally smooth (Fig. 8B) or with scattered small punctures; hairs on dorsum of the body somewhat long and erect to suberect . . . . . 9

9
return to couplet #8
 * In profile, petiolar node roughly as long as high (LNI: 90–106); in lateral view, posterolateral border of propodeum with a distinct toothlike lobe (Fig. 9A) . . . . . Leptogenys fiandry


 * In profile, petiolar node distinctly longer than high (LNI: 88); in lateral view, propodeal lobe indistinct (Fig. 9B) . . . . . Leptogenys anjara

10
return to couplet #6
 * Distance between anterior margin of torulus and anteromedian margin of clypeus distinctly less than the distance between outer margin of torulus and outer margins of base of mandibles; mandibles elongate and narrow, strongly crossing each other or superimposed when fully closed against the anterior margin of clypeus; anterior clypeal margin widely transverse, broadly rounded or convex, dorsoventrally thick and with white yellowish lamella (Fig. 10A) . . . . . 11


 * Distance between anterior margin of torulus and anteromedian margin of clypeus equal to or greater than the distance between outer margin of torulus and outer margins of base of mandibles; mandibles short and robust, subtriangular or with convex inner margin, not strongly crossing each other, the apices meeting or slightly overlapping when fully closed against anterior margin of clypeus; anterior clypeal margin medially projecting into a triangular lobe, dorsoventrally thin, with sharp edge or subopaque lamella (Fig. 10B) . . . . . 19

11
return to couplet #10
 * Clypeus without median longitudinal carina; in full-face view, distal half of mandible distinctly broadened, the inner margin of which gradually becomes narrower and broadly arched toward the sharp apical tooth; distal half of blades lacking piligerous punctures (Fig. 11A); in profile, mandible curved dorsally, with midpoint distinctly dorsal of mandible insertion . . . . . 12


 * Clypeus with median longitudinal carina; in full-face view, distal half of blades not clearly broadened, the inner margin continuously broadly concave from base to near the apical tooth; distal half of mandible with sparse piligerous punctures (Fig. 11B); in profile, mandible projecting anteriorly from base, with midpoint of mandible more or less at same level as mandible insertion . . . . . 13

12
return to couplet #11
 * In full-face view, anterior margin of clypeus broadly rounded, the lateral portion rounding to the anterior margin; mandible clearly broadened and flattened at about mid-length, with longitudinal and fine striation, and evenly curved into a sharp apical tooth (Fig. 12A); in profile, third abdominal segment microreticulate (coriaceous) with scattered punctures; dorsum of mesosoma, petiolar node, and gaster without pubescence . . . . . Leptogenys diana


 * In full-face view, anterior margin of clypeus transverse and wide, the junction of lateral portion to the anterior margin angulate; apical half of mandible not very broadly flattened, effaced fine striation may be present (Fig. 12B); in profile, third abdominal segment densely punctulate, dorsum of mesosoma, petiolar node and gaster with abundant pubescence . . . . . Leptogenys truncatirostris

13
return to couplet #11
 * In full-face view, clypeus distinctly broadly rounded; distance between anterior margin of torulus and anteromedian margin of clypeus approximately equal to or less than maximum diameter of antennal scape; mandible blades generally following the rounded shape of anterior clypeal margin when tightly closed against the latter (Fig. 13A) . . . . . 14


 * In full-face view, clypeus not distinctly broadly rounded; distance between anterior margin of torulus and anteromedian margin of clypeus (including the white yellowish lamella) greater than the maximum diameter of antennal scape; mandible not following the shape of anterior clypeal margin when tightly closed (Fig. 13B) . . . . . 16

14
return to couplet #13
 * In full-face view, head clearly broader than long (CI: 105–109) (Fig. 14A) . . . . . Leptogenys alatapia


 * In full-face view, head about as long as broad or longer than broad (CI: 82–97) (Fig. 14B) . . . . . 15

15
return to couplet #14
 * Dorsum of head, mesosoma, petiole, and gaster covered with conspicuous pubescence but with few suberect short hairs (Fig. 15A); antennal scape relatively short (SI: 103–112); larger species (HW: 1.18–1.38, HL: 1.27–1.43, WL: 2.08–2.32) . . . . . Leptogenys arcirostris


 * Dorsum of head, mesosoma, petiole, and gaster with reduced pubescence, and covered with long standing erect and suberect hairs (Fig. 15B); antennal scape relatively long (SI: 111–129); smaller species (HW: 0.97–1.01, HL: 1.05–1.10, WL: 1.77–1.87) . . . . . Leptogenys borivava

16
return to couplet #13
 * Antennal scape longer (SL: 1.67–1.99, SI: 122–129); eye maximum diameter twice as large as maximum width of antennal scape (Fig. 16A) . . . . . Leptogenys ridens


 * Antennal scape shorter (SL: 1.15–1.66, SI: 111–120); eye maximum diameter less than twice maximum scape width (Fig. 16B . . . . . 17

17
return to couplet #16
 * In full-face view, eye maximum diameter between one third and one fourth of the length of side of the head; in the same view eye extending beyond lateral border of the head (Fig. 17A) . . . . . Leptogenys fotsivava


 * In full-face view, eye maximum diameter roughly one fifth of the length of sides of the head; in the same view, eye not extending beyond lateral border of the head (Fig. 17B) . . . . . 18

18
return to couplet #17
 * In dorsal view, petiolar node broader than long (DNI: 134–146); dorsum of mesosoma, petiolar node and gaster with abundant short suberect hairs and reduced amount of pubescence; sculpture of these sclerites much coarser (Fig. 18A); head subquadrate; smaller species (HW: 1.20–1.34, HL: 1.42–1.56, WL: 2.17–2.39) . . . . . Leptogenys tsingy


 * In dorsal view, petiolar node approximately as broad as long (DNI: 115); dorsum of mesosoma, petiolar node and gaster with few short suberect hairs and dense pubescence; sculpture of these sclerites denser and finer (Fig. 18B); head distinctly broader anteriorly; larger species (HW: 1.38, HL: 1.58, WL: 2.47) . . . . . Leptogenys namoroka

19
return to couplet #10
 * Dorsum of head and mesosoma smooth apart from small piligerous punctures (Fig. 19A) . . . . . 20


 * Sculpture on dorsum of head and pronotum variable, densely reticulate-rugulose, densely reticulate-punctulate, densely punctate to scattered punctures (Fig. 19B, 19C) . . . . . 32

20
return to couplet #19
 * Third antennal segment at least twice as long as the second segment (Fig. 20A); in dorsal view, petiolar node elongate (DNI≤ 52), strongly narrowed anteriorly (Fig. 20B) . . . . . 21


 * Third antennal segment less than twice as long as the second segment (Fig. 20C); in dorsal view, petiolar node subrectangular (DNI≥ 61), only weakly narrowed anteriorly (Fig. 20D) . . . . . 23

21
return to couplet #20
 * Third antennal segment twice as long as the second; in dorsal view mesonotum broader than long (Fig. 21A); smaller species (HL: 1.38–1.48) . . . . . Leptogenys johary


 * Third antennal segment more than twice as long as the second; in dorsal view mesonotum as long as broad (Fig. 21B); larger species (HL≥ 1.77) . . . . . 22

22
return to couplet #21
 * Maximum diameter of eye less than twice the maximum width of antennal scape (Fig. 22A); leg and antenna very long (SI: 263); body light reddish brown . . . . . Leptogenys zohy


 * Maximum diameter of eye two or more times the maximum width of antennal scape (Fig. 22B); leg and antennna shorter (SI: 163–203); body color dark brown to reddish brown . . . . . Leptogenys angusta

23
return to couplet #20
 * In full-face view, eye not breaking the outline of the side of the head (Fig. 23A) . . . . . 24


 * In full-face view, eye breaking the outline of the side of the head (Fig. 23B) . . . . . 26

24
return to couplet #23
 * Mandible punctulate, with fine and short longitudinal striation or dense and fine elongate punctures (Fig. 24A); standing hairs present on propodeal dorsum; with petiole in profile, the anterodorsal angle without an impression; larger species (HW: 1.52–1.74, PW: 1.23–1.46); black in color with bluish reflection or opalescence . . . . . Leptogenys coerulescens


 * Mandible smooth and shining between sparse punctures (Fig. 24B); standing hairs either absent on propodeal dorsum, or present but very short and reduced in number; with petiole in profile, often with an impression immediately posterior to the anterodorsal angle; smaller species (HW: 0.96–0.98, PW: 0.80–0.83); color black without bluish reflection or opalescence . . . . . 25

25
return to couplet #24
 * Mesopleural sulcus narrow and smooth, oriented to the level of posterodorsal corner of pronotum; antennae and legs basally black to dark brown, antennal apical portion and tarsi brown (Fig. 25A); larger species (HL: 1.48–1.84, WL: 2.29–2.90) . . . . . Leptogenys malama


 * Mesopleural sulcus broad and shallow, transversely sculptured, oriented to the level of posteroventral corner of pronotum; antennae and legs brown to light brown towards apical portion (Fig. 25B); smaller species (HL: 1.32–1.43, WL: 2.09–2.25) . . . . . Leptogenys lucida

26
return to couplet #23
 * Mandible sculptured, longitudinally striate at least from near the base to the point of preapical tooth insertion, and then microreticulate or smooth with sparse piligerous punctures; in lateral view, posterodorsal corner of petiolar node protruding posteriorly and overhanging posterior face (Fig. 26A) . . . . . 27


 * Mandible smooth and shining between scattered piligerous punctures; in lateral view, dorsal and posterior faces of petiolar node meeting at right angle, not projecting posteriorly nor overhanging the posterior face of the node (Fig. 26B) . . . . . 28

27
return to couplet #26
 * In profile, metapleuron finely rugulose (Fig. 27A); sometimes dorsal and posterior portions of mesopleuron finely rugulose or with superficial rugulae . . . . . Leptogenys grandidieri


 * In profile, metapleuron generally smooth and shiny, mesopleuron smooth or with scattered punctures (Fig. 27B) . . . . . Leptogenys manongarivo

28
return to couplet #26
 * In profile, portions of each side of mesometapleural suture, metapleuron, and the suture between propodeum and metapleuron finely rugose (Fig. 28A) . . . . . 29


 * In profile, each side of mesometapleural suture, metapleuron, and the suture between propodeum and metapleuron generally smooth (Fig. 28B) . . . . . 30

29
return to couplet #28
 * Mandibles covered with fine microreticulation and sparse piligerous punctures; median lobe of clypeus longitudinally striate (Fig. 29A) (Comoros, Mayotte) . . . . . Leptogenys comajojo


 * Mandibles smooth and shining between scattered piligerous punctulae; median lobe of clypeus mostly smooth and not markedly striate (Fig. 29B) . . . . . Leptogenys edsoni

30
return to couplet #28
 * In dorsal view, petiole elongate, node roughly twice as long as wide (DNI: 61–67) (Fig. 30A) . . . . . Leptogenys mangabe


 * In dorsal view, petiolar node broader, less than twice as long as wide (Fig. 30B, 30C) . . . . . 31

31
return to couplet #30
 * In dorsal view, petiole robust (DNI: 83–89), width decreasing gradually from back to front, but anterior portion of node not notably compressed laterally (Fig. 30C); in lateral view, the node approximately as long as high (LNI 100–106), anterior sharp rim separate from the anterior face of node (Fig. 31A); dorsum of body with whitish hairs; larger in size (HW: 1.20–1.31, PW: 0.98–1.11) . . . . . Leptogenys fasika


 * In dorsal view, petiolar node more elongate (DNI: 67–86), anterior portion markedly narrower and distinctly compressed laterally (Fig. 30B); in lateral view, the node longer than high (LNI: 91–105), anterior rim attached directly to anterior face of node (Fig. 31B); dorsum of body with yellowish brown hairs; generally smaller in size (HW: 0.75–1.08, PW: 0.60–0.91) . . . . . Leptogenys variabilis

32
return to couplet #19
 * Mandible subtriangular, inner margin at about mid-length with a distinct basal angle (Fig. 32A); in profile, posterolateral margin of petiolar node without denticle or blunt angle, dorsum of pronotum either finely reticulate-rugulose or transversely finely striate-rugulose . . . . . 33


 * Mandible subfalcate, inner margin without a basal angle at mid-length (Fig. 32B); in profile, posterolateral margin of petiolar node with small tooth, denticle or blunt angle; dorsum of pronotum densely punctate or foveate to sparsely punctate, sometimes superimposed with fine transverse rugulae . . . . . 34

33
return to couplet #32
 * In full-face view, eye breaking the outline of the side of the head (Fig. 33A); dorsum of head and promesonotum reticulate-rugulose; in full-face view, masticatory margin of mandible much shorter than basal margin . . . . . Leptogenys oswaldi


 * In full-face view, eye not breaking the outline of the side of the head (Fig. 33B); head capsule reticulate-punctulate, promesonotal dorsum transversely striate, with scattered small punctures; in full-face view, masticatory margin of mandible about equal in length to basal margin . . . . . Leptogenys mayotte

34
return to couplet #32
 * With mesosoma in dorsal view, metanotal groove distinctly visible (Fig. 34A) . . . . . 35


 * With mesosoma in dorsal view, metanotal groove indistinct (Fig. 34B) . . . . . 37

35
return to couplet #34
 * In dorsal view, posterior margin of petiolar node medially emarginated (Fig. 35A) . . . . . Leptogenys saussurei


 * In dorsal view, posterior margin of petiolar node straight, not medially emarginated (Fig. 35B) . . . . . 36

36
return to couplet #35
 * Smaller species (HW 1.49–1.73, HL 2.02–2.29); in profile posterolateral margin of petiolar node with a small sharp tooth (Fig. 36A) . . . . . Leptogenys lohahela


 * Larger species (HW 1.79–1.92, HL 2.61–2.85); in profile posterolateral margin of petiolar node with a blunt lobe or angle, not a small sharp tooth (Fig. 36B) . . . . . Leptogenys acutirostris

37
return to couplet #34
 * In dorsal view, posterior margin of petiolar node straight, not medially excised (Fig. 37A) . . . . . Leptogenys ambo


 * In dorsal view, posterior margin of petiolar node noticeably medially excised (Fig. 37B) . . . . . 38

38
return to couplet #37
 * Apical margin of mandible clearly with three teeth, the apical and two preapical teeth (Fig. 38A) . . . . . Leptogenys vatovavy


 * Apical margin of mandible with two teeth, one preapical and one apical tooth (Fig. 38B) . . . . . 39

39
return to couplet #38
 * Mandible longitudinally striate; head longitudinally rugulose, dorsum of pronotum and mesonotum densely punctate superimposed with transverse rugulae; larger species (HW: 1.77, HL: 2.29, PW: 1.45); anteromedian clypeal margin broadly angulate (Fig. 39A) . . . . . Leptogenys andritantely


 * Mandible smooth and shiny between scattered punctures; head densely punctulate to punctate; dorsum of pronotum and mesonotum punctate; smaller species (HW: 0.98–1.04, HL: 1.34–1.44, PW: 0.86–0.94); anteromedian clypeal margin bidentate (Fig. 39B) . . . . . Leptogenys ralipra

40
return to couplet #1
 * In full-face view, eye diameter usually less than the greatest width of antennal scape; mandible short and more or less straight (Fig. 40A) . . . . . Leptogenys rabebe


 * In full-face view, eye diameter markedly greater than the maximum width of antennal scape; mandible long and narrow, more arched from the base to the apex (Fig. 40B) . . . . . 41

41
return to couplet #40
 * Dorsum of head, mesosoma, petiolar node, and the first two gastral segments without standing hairs, but strongly shagreened and covered with dense pruinose pubescence (Fig. 41A) . . . . . 42


 * Dorsum of at least some parts of the body covered with standing hairs, not shagreened nor densely covered with pubescence (Fig. 41B) . . . . . 44

42
return to couplet #41
 * In full-face view, translucent lamella on anterior clypeal margin broad, rounded (Fig. 42A) . . . . . Leptogenys pavesii


 * In full-face view, translucent lamella on anterior clypeal margin narrow, obtusely angulate (Fig. 42B) . . . . . 43

43
return to couplet #42
 * In dorsal view, petiolar node distinctly broader than long (DNI: 113–133) (Fig. 43A) . . . . . Leptogenys maxillosa


 * In dorsal view, petiolar node most often clearly longer than broad, at least as long as broad (DNI: 93–109) (Fig. 43B) . . . . . Leptogenys falcigera

44
return to couplet #41
 * Third antennal segment approximately twice as long as the second; dorsum of head smooth apart from scattered punctures (Fig. 44A); pronotum weakly sculptured dorsally; constriction between third and fourth abdominal segments indistinct . . . . . Leptogenys stuhlmanni


 * Third antennal segment less than twice as long as the second; dorsum of head and mesosoma very strongly sculptured (Fig. 44B); constriction between third and fourth abdominal segments noticeably distinct . . . . . 45

45
return to couplet #44
 * Anteromedian lobe of clypeus without anteriorly projecting peg-like setae near its margin above the lamella (Fig. 45A); larger species (HW: 1.87–2.49, PW: 1.37–1.47) . . . . . 46


 * Anteromedian lobe of clypeus with two, three or more anteriorly projecting peg-like setae near its margin above the lamella (Fig. 45B); smaller species (HW: 1.08–1.73, PW: 0.82–1.22) . . . . . 48

46
return to couplet #45
 * In full-face view, eye not breaking lateral margin of the head; median portion of clypeus projecting anteriorly into a narrowly angulate lobe; lamella confined to this narrowly shaped anteromedian lobe (Fig. 46A) . . . . . Leptogenys alluaudi


 * In full-face view, eye breaking lateral margin of the head; anterior clypeal margin broadly triangular, with the surrounding lamella extending to the lateral portion of clypeus (Fig. 46B) . . . . . 47

47
return to couplet #46
 * Head more elongate (CI: 85), mandible broader, strongly curved near the base, entire surface of the blade with dense and fine longitudinal striations (Fig. 47A) . . . . . Leptogenys incisa


 * Head broader (CI: 94–97), mandible narrower, not strongly curved near the base, with smooth and shiny blade apart from sparse piligerous punctures; fine striation apparently effaced (Fig. 47B) . . . . . Leptogenys pilaka

48
return to couplet #45
 * Anterior clypeal margin a broad angle with blunt apex or generally convex; with the bordering translucent lamella, if present, extending to the lateral portion of the clypeus, not confined to the anteromedian lobe (Fig. 48A) . . . . . 49


 * Anterior clypeal margin not a broad angle, but rather consisting medially of a narrowly rounded (Fig. 48B) or triangular (Fig. 48C) lobe, or spine; and, if present, lamella confined to this anteromedian lobe . . . . . 55

49
return to couplet #48
 * Antennal scape relatively long (SI ≥130), more than its apical third extending beyond posterior margin of the head (Fig. 49A) . . . . . 50


 * Antennal scape relatively short (SI≤ 123), less than its apical third extending beyond posterior margin of the head (Fig. 49B) . . . . . 52

50
return to couplet #49
 * Mandibles finely longitudinally striate, with piligerous pits; with head in full-face view, the convex inner margin of mandible with distinct broad convexity approximately at apical third portion of the blade (Fig. 50A) . . . . . Leptogenys antongilensis


 * At least the basal half of mandibles mostly smooth and shining with scattered piligerous pits; with head in full-face view, the inner margin of mandible evenly concave (Fig. 50B) or slightly convex (Fig. 51A) along their length . . . . . 51

51
return to couplet #50
 * In full-face view, fringing lamella of the clypeus broad, width roughly the same as the minimum diameter of antennal scape; mandibles strongly curved near the base and blades much broader, the inner margins weakly convex (Fig. 51A); in dorsal view, mesosoma apparently with four distinct segments (Fig. 52A) . . . . . Leptogenys tatsimo


 * In full-face view, fringing lamella of the clypeus narrow, the width less than the minimum diameter of antennal scape; mandible not strongly curved near the base and blades narrower, the inner margins concave along their length (Fig. 51B); in dorsal view, mesosoma with three visible segments (Fig. 52B) . . . . . Leptogenys manja

52
return to couplet #49
 * In dorsal view, mesosoma seemingly with four visible segments, an additional protruding small sclerite (a partially differentiated metanotum) distinctly visible within the metanotal groove (Fig. 52A) . . . . . 53


 * In dorsal view, mesosoma consists of three visible segments, with no additional discernible segment in the metanotal groove (Fig. 52B) . . . . . 54

53
return to couplet #52
 * In full-face view, three to four anteriorly projecting, peg-like setae present near margin of anteromedial lobe of clypeus, above the translucent lamella; fringing lamella usually broadly rounded; mandibles mostly smooth and shiny between sparse piligerous punctures (Fig. 53A) . . . . . Leptogenys suarensis


 * In full face-view, only two anteriorly projecting peg-like setae present near margin of anteromedial clypeal portion, above the translucent lamella; translucent lamella narrowly triangular; mandibles striate at least along apical half, interspersed with punctures (Fig. 53B) . . . . . Leptogenys gracilis

54
return to couplet #52
 * Median clypeal carina sharp; with head in full-face view, hypostomal teeth visible (Fig. 54A); smaller species (HW: 1.10–1.25, WL: 2.25–2.64) . . . . . Leptogenys namana


 * Median clypeal carina blunt; with head in full-face view, hypostomal teeth not visible (Fig. 54B); larger species (HW: 1.51–1.55, WL: 2.92–3.10) . . . . . Leptogenys imerinensis

55
return to couplet #48
 * Median portion of clypeus projecting anteriorly into a short, narrowly rounded lobe; antennal scape lacking erect hairs, or if present, the length less than greatest width of scape (Fig. 55A); with petiole in profile, posterior margin of node with constriction at the posteroventral angle near the junction to gaster . . . . . 56


 * Median portion of clypeus projecting anteriorly into a narrowly angulate lobe or spine; antennal scape with erect hairs whose length is as great as or greater than maximum width of scape (Fig. 55B); with petiole in profile, posterior margin of node without constriction at the posteroventral angle . . . . . 58

56
return to couplet #55
 * In full-face view, eye not breaking the outline of side of the head; larger species (HW: 1.30–1.59, WL: 2.26–2.72) (Fig. 56A) . . . . . Leptogenys voeltzkowi


 * In full-face view, eye breaking the outline of side of the head; smaller species (HW: 1.08–1.32, WL: 2.26–2.47) (Fig. 56B) . . . . . 57

57
return to couplet #56
 * Mandible almost straight without a visible curve near the base; antennal scape and tibia with erect to suberect short hairs (Fig. 57A); third abdominal tergite densely punctate . . . . . Leptogenys vitsy


 * Mandible with curved angle near the base; antennal scape and tibia with subdecumbent, short hairs (Fig. 57B); third abdominal tergite finely reticulate-rugose . . . . . Leptogenys sahamalaza

58
return to couplet #55
 * Median portion of clypeus projecting anteriorly into a toothlike spine; basal portion of mandible broadly curved, distinctly extending laterally beyond level of outline of the side of head (Fig. 58A) . . . . . Leptogenys lavavava


 * Median portion of clypeus not projecting into a toothlike spine; basal portion of mandible slightly to distinctly curved, but not extending beyond level of outline of the side of head (Fig. 58B, 58C) . . . . . 59

59
return to couplet #58
 * Dorsum of head and body with standing hairs longer than the maximum diameter of eyes; in full-face view, head more or less elongate (CI: 80–84), mandible not strongly arched near the base and inner margin evenly slightly concave from the base to the apex (Fig. 59A); antennal scape relatively long (SI> 133), apical third surpassing the posterior margin of head . . . . . Leptogenys barimaso


 * Dorsum of head and body with standing hairs whose length is less than the maximum diameter of eyes; in full-face view, head shorter (CI: 83–88), mandible distinctly arched near the base and becomes feebly concave to almost straight towards the apex (Fig. 59B); antennal scape usually short (SI< 133); only the apical fourth surpassing the posterior margin of head . . . . . Leptogenys chrislaini