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

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