Key to New World Gnamptogenys workers

This worker key is based on: [[Media:Camacho, G.P., Franco, W. et al. 2020. Additions to the taxonomy of Gnamptogenys.pdf|Camacho, G.P., Franco, W., Feitosa, R.M. 2020. Additions to the taxonomy of Gnamptogenys Roger (Hymenoptera: Formicidae: Ectatomminae) with an updated key to the New World species. Zootaxa 4747: 450 476]]. This key replaces a New World Gnamptogenys key published by Lattke, Fernández, and Palacio 2007.

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1

 * In dorsal view, promesonotal suture well marked, totally interrupting dorsal mesosomal sculpture (Fig. 1A); in frontal view, frontal carina not expanded or, if expanded into frontal lobe, not completely covering all of base of scape, at least neck visible; in lateral view, petiolar spiracle facing ventrolaterally, not in depression . . . . . 2


 * In dorsal view, promesonotal suture absent to well-impressed but never interrupting dorsal mesosomal sculpture (Fig. 1B); in frontal view, frontal carina not expanded or, if expanded into frontal lobe, not completely covering base of scape, with at least neck visible; in lateral view, petiolar spiracle facing ventrolaterally, not in depression (also see third lug) . . . . . 31


 * In dorsal view, promesonotal suture absent to lightly impressed, never interrupting dorsal mesosomal sculpture (Fig. 1C); in frontal view, frontal carina expanded into a frontal lobe, covering all of scape base, including condyle and neck; in lateral view, petiolar spiracle facing ventrally, located in depression . . . . . A species of Alfaria

2
return to couplet #1
 * In dorsal view, vertex smooth and shiny, sometimes presenting faded striae or rugulae, but never costulate or heavily sculptured; in frontal view, scape not reaching or slightly surpassing the vertex margin, never by more than twice its larger diameter; in lateral view, petiolar node with semiparallel anterior and posterior margins, both forming approximate right angles with the dorsal margin . . . . . 3


 * In dorsal view, vertex completely sculptured, with well-marked costulae; in frontal view, scape always surpassing the vertex margin; in lateral view, petiolar node with a single curved anterodorsal margin or anterior and dorsal margins separated by a blunt angle . . . . . 9

3
return to couplet #2
 * In dorsal view, mesosomal dorsum totally sculptured, usually costulate or rugulose (Fig. 2A) . . . . . 4


 * In dorsal view, mesosomal dorsum with large smooth and shiny areas (Fig. 2B) . . . . . 8

4
return to couplet #3
 * In dorsal view, segments I and II of gaster (abdominal segments III and IV) totally sculptured, costulate or rugulose . . . . . 5


 * In dorsal view, segments I and II of gaster (abdominal segments III and IV) smooth and shiny, sometimes with small striae at the base of the hairs . . . . . 7

5
return to couplet #4
 * In dorsal view, segment I of gaster (abdominal segment III) transversely rugulose; body yellowish. Brazil (PA) and Hispaniola. . . . . Gnamptogenys haytiana


 * In dorsal view, segment I of gaster (abdominal segment III) longitudinally costulate; body black to dark brown . . . . . 6

6
return to couplet #5
 * In frontal view, scape slightly surpassing the vertex margin; in lateral view, propodeal spiracle strongly projecting from integument, forming a tubuliform projection. Guyana . . . . . Gnamptogenys avus


 * In frontal view, scape not reaching the vertex margin; in lateral view, propodeal spiracle not projected. Bolivia, Brazil (AM, BA, PA), Colombia, Ecuador, French Guiana, Mexico, Peru and Venezuela . . . . . Gnamptogenys mina

7
return to couplet #4
 * In frontal view, scape not reaching the vertex margin; metacoxal dorsum with a lobe or denticle; in dorsal view, segments I and II of gaster (abdominal segments III and IV) covered by small ridges or striae, extending from the base of the hairs. Brazil (MG, RS, SC, SP) . . . . . Gnamptogenys lavra


 * In frontal view, scape slightly surpassing the vertex margin; metacoxal dorsum unarmed; in dorsal view, segments I and II of gaster (abdominal segments III and IV) completely smooth and shiny. Brazil (SC) . . . . . Gnamptogenys lenis

8
return to couplet #3
 * In dorsal view, metanotal groove well-impressed, interrupting dorsal mesosomal sculpture; metacoxal dorsum unarmed; in lateral view, propodeal declivity lacking lobes; propodeal spiracle located directly on the declivity margin, elevated above the integument; in dorsal view, declivitous face of propodeum with transverse costulae. Brazil (AM, PA, MT, RO), Colombia, French Guiana, Guyana, Peru, Suriname and Venezuela . . . . . Gnamptogenys relicta


 * In dorsal view, metanotal groove absent; metacoxal dorsum with a lobe or denticle; in lateral view, propodeal declivity with anterolateral lobe; propodeal spiracle distant from declivity margin; in dorsal view, declivitous face of propodeum smooth and shiny, with some inconspicuous striae. Brazil (MG, PR, RJ, RS, SP, SC), Colombia and Venezuela . . . . . Gnamptogenys reichenspergeri

9
return to couplet #2
 * In dorsal view, mesosomal dorsum with a well-defined metanotal groove (Fig. 3A) . . . . . 10


 * Metanotal groove absent (Fig. 3B) . . . . . 14

10
return to couplet #9
 * In dorsal view, segments I and II of gaster (abdominal segments III and IV) smooth and shiny. Colombia . . . . . Gnamptogenys gentryi


 * In dorsal view, segments I and II of gaster (abdominal segments III and IV) longitudinally costulate . . . . . 11

11
return to couplet #10
 * In lateral view, subpetiolar process subquadrate, with a posterior angle . . . . . 12


 * In lateral view, subpetiolar process forming an anterior projecting lobe, without a posterior angle . . . . . 13

12
return to couplet #11
 * In dorsal view, area between promesonotal suture and metanotal groove narrow and of uniform width; anterior mesonotal margin convex. Belize, Brazil (PA), Colombia, Costa Rica, Ecuador, Mexico and Panama . . . . . Gnamptogenys bisulca


 * In dorsal view, area between promesonotal suture and metanotal groove wide and ovaloid; anterior mesonotal margin forms a blunt angle. Colombia . . . . . Gnamptogenys dichotoma

13
return to couplet #11
 * In frontal view, anterior margin of clypeal lamella bluntly angular; in dorsal view, vertex longitudinally costulate. Colombia . . . . . Gnamptogenys brunnea


 * In frontal view, anterior margin of clypeal lamella evenly convex; in dorsal view, vertex with less than five transverse costulae. Colombia and Panama . . . . . Gnamptogenys auricula

14
return to couplet #9
 * In lateral view, petiolar node erect, the dorsal margin separated from the anterior and posterior margins by blunt angles (Fig. 4A) . . . . . 15


 * In lateral view, petiolar node posteriorly inclined, with a broadly curved anterodorsal margin contrasting with the angle separating the dorsal margin from the posterior margin (Fig. 4B, C) . . . . . 18

15
return to couplet #14
 * In frontal view, scape longer than the total head length, surpassing the vertex margin by almost half its length; in frontal view, lateral margins of the head convex; in lateral view, dorsal face of mesosoma flat, without metanotal impression. Argentina, Bolivia, Brazil (widespread), Colombia, Ecuador, French Guiana, Paraguay, Peru, Suriname and Venezuela . . . . . Gnamptogenys moelleri


 * In frontal view, scape never longer than the total head length, surpassing the vertex margin by a third or less of its length; in frontal view, lateral margins of head subparallel to divergent, never convex; in lateral view, dorsal face of mesosoma convex, with or without metanotal impression . . . . . 16

16
return to couplet #15
 * In frontal view, eye located in a depression in the head, the outer margin slightly surpassing the lateral margin of the head; scape very short, surpassing the vertex margin by 1/6 of its length; in lateral view, dorsal face of mesosoma completely convex, without metanotal impression. Brazil (BA, PA, PB, PE, PI, PR, RS, SE) . . . . . Gnamptogenys pernambucana


 * In frontal view, eye not located in a depression, the outer margin strongly surpassing the lateral margin of the head; scape length variable, surpassing the vertex margin by at least ¼ of its length; in lateral view, dorsal face of mesosoma convex with a visible metanotal impression . . . . . 17

17
return to couplet #16
 * Scape covered by dense decumbent pilosity; in frontal view, several long, erect hairs projecting from the head dorsum, mandible and scape; in lateral view, dorsal meso and metasoma with relatively longer, erect, amber colored hairs; in dorsal view, propodeal declivity with 1-3 transverse costulae; in lateral view, subpetiolar process subquadrate or more often with an anteriorly projected lobe. Argentina, Bolivia, Brazil (widespread), Colombia, Costa Rica, Ecuador, El Salvador, French Guiana, Guyana, Guatemala, Hispaniola, Honduras, Jamaica, Lesser Antilles, Mexico, Nicaragua, Panama, Paraguay, Peru, Puerto Rico, Suriname, Trinidad and Tobago, Uruguay and Venezuela . . . . . Gnamptogenys striatula


 * Scape with sparse decumbent pilosity, not covering the entire structure; in frontal view head dorsum and mandible with short, stout, suberect hairs; in lateral view, dorsal meso and metasoma with relatively sparser, shorter, stout, suberect, white colored hairs; propodeal declivity devoid of transverse costulae; in lateral view, subpetiolar process subquadrate, without an anterior lobe. Brazil (MA), Guyana and Venezuela. . . . . Gnamptogenys ammophila

18
return to couplet #14
 * In lateral view, petiolar node with blunt or pointed apex overhanging the posterior margin (Fig. 5A); in ventral view, subpetiolar process with edges of mostly uniform width, widening only at the union with sternite . . . . . 19


 * In lateral view, petiolar node apex barely overhanging posterior margin (Fig. 5B); in ventral view, subpetiolar process cuneiform, anteriorly of uniform width, widening posteriorly into a bifurcate process . . . . . 26

19
return to couplet #18
 * Petiolar node with an acute apex in lateral view. Bolivia, Brazil (AM), Colombia and Ecuador . . . . . Gnamptogenys acuta


 * Petiolar node with a blunt apex in lateral view . . . . . 20

20
return to couplet #19
 * In dorsal view, vertex usually with 4–5 transverse costulae next to vertexal carina, extending across the width of the vertex (Fig. 6A); in ventral view, first gastral sternite with a median smooth and shiny area. Brazil (BA, MG), Colombia, French Guiana, Guyana, Suriname and Venezuela . . . . . Gnamptogenys gracilis


 * In dorsal view, vertex usually without transverse costulae (Fig. 6B), or when transverse costulae are present, they are limited to the center of the vertex (Fig. 6C) or are not continuous across the vertex (Fig. 6D); in ventral view, first gastral sternite totally costulate or striate . . . . . 21

21
return to couplet #20
 * Scape with more than 10 long, erect hairs, not including underlying pubescence . . . . . 22


 * Scape with fewer than 10 long, erect hairs, not including underlying pubescence . . . . . 24

22
return to couplet #21
 * In lateral and dorsal views, body striate, sculpture relatively finer; in lateral view, body with dense pubescence under abundant erect hairs; dorsal margin of femur with erect to suberect hairs. Colombia . . . . . Gnamptogenys pilosa


 * In lateral and dorsal views, body costulate or striate, sculpture relatively coarser; in lateral view, body with sparse pubescence under erect hairs; dorsal margin of femur with decumbent to subdecumbent hairs . . . . . 23

23
return to couplet #21
 * In dorsal view, body striate or costulate, with abundant decumbent pubescence; in lateral view, subpetiolar process forming a rounded lobe, without sharp angles; body and legs brown. Colombia . . . . . Gnamptogenys ejuncida


 * In dorsal view, body usually costate, with sparse decumbent pubescence; in lateral view, subpetiolar process usually with a sharp anterior angle, blunt in Central American specimens; body black and legs ferruginous. Bolivia, Brazil (MG, MS, MT), Colombia, Costa Rica, Ecuador, French Guiana, Guatemala, Honduras, Mexico, Nicaragua, Peru and Venezuela . . . . . Gnamptogenys porcata

24
return to couplet #21
 * Scape and tibia with one or no semierect or semidecumbent hairs. Colombia and Ecuador . . . . . Gnamptogenys extra


 * Scape and tibia with five or more erect hairs . . . . . 25

25
return to couplet #24
 * In dorsal view, propodeal declivity with transverse costulae; in lateral view, propodeal spiracle distant from the declivitous face of propodeum by at least the length of its opening; petiolar node slightly pedunculate. Bolivia, Brazil (widespread), Colombia, Ecuador, French Guiana, Lesser Antilles, Panama, Peru, Suriname, Trinidad and Tobago and Venezuela . . . . . Gnamptogenys pleurodon


 * In dorsal view, propodeal declivity with longitudinal costulae; in lateral view, propodeal spiracle located closer than the length of its opening to the declivitous face margin; petiolar node sessile. Colombia . . . . . Gnamptogenys nigrivitrea

26
return to couplet #18
 * In lateral view, propodeal dorsum depressed below level of mesonotum; dorsal and declivitous propodeal faces separated by a ridge; postpetiolar sternite with weakly-defined rugulae. Ecuador and Venezuela . . . . . Gnamptogenys pittieri


 * In lateral view, propodeal dorsum not depressed below level of mesonotum; dorsal and declivitous propodeal faces confluent;postpetiolar sternite with well-defined costulae or striae . . . . . 27

27
return to couplet #25
 * Scape with dense white pubescence and 0–2 erect hairs. Bolivia . . . . . Gnamptogenys ilimani


 * Scape with moderate to sparse pubescence and dense decumbent pilosity, with five or more erect hairs . . . . . 28

28
return to couplet #27
 * Head with relatively smaller eyes (OI<0.16); in lateral view, dorsum of mesonotum and propodeum continuous, not separated by a metanotal impression; larger species (HW≥0.84 mm, WL≥0.35 mm) . . . . . 29


 * Head with relatively larger eyes (OI ≥ 0.16); in lateral view, dorsum of mesonotum and propodeum separated by a metanotal impression; smaller species (HW<0.84 mm, WL<0.35 mm) . . . . . 30

29
return to couplet #28
 * In lateral view, subpetiolar process with a poorly developed fenestra. Bolivia. . . . . Gnamptogenys aspera


 * In lateral view, subpetiolar process with a well-developed fenestra. Colombia and Ecuador. . . . . Gnamptogenys andina

30
return to couplet #28
 * In frontal view, vertex margin concave; in dorsal view, humerus rounded; in lateral view, propodeal dorsum depressed in relation to the mesonotal dorsum. Belize, Colombia, Costa Rica, Ecuador, French Guiana, Guatemala, Guyana, Honduras, Jamaica, Mexico, Nicaragua, Panama and Suriname . . . . . Gnamptogenys strigata


 * In frontal view, vertex margin straight; in dorsal view, humerus angulate; in lateral view, dorsum of propodeum and mesonotum continuous, propodeum not depressed relative to mesonotum. Brazil (BA) . . . . . Gnamptogenys latistriata

31
return to couplet #1
 * In frontal view, scape not reaching the vertex margin (Fig. 7A) . . . . . 32


 * In frontal view, scape surpassing vertex margin by at least one apical width (Fig. 7B) . . . . . 49

32
return to couplet #31
 * Mandibular dorsum with striae, costulae or rugulae on at least 1/4 of its length (Fig. 8A) . . . . . 33


 * Mandibular dorsum totally smooth and shiny, with sparse punctuation (Fig. 8B) . . . . . 35

33
return to couplet #32
 * In frontal view, mandible falcate; body with irregular costulae. Hispaniola (known only from the queen caste). . . . . Gnamptogenys falcaria


 * In frontal view, mandible triangular or semitriangular; body with regular striae or costulae . . . . . 34

34
return to couplet #33
 * Mandibular dorsal surface densely striate; eyes small (OI<0.1); metacoxal dorsum unarmed. Argentina, Bolivia, Brazil (AC, AM, BA, GO, MG, MT, PA, RO, SP), Colombia, Costa Rica, Ecuador, French Guiana, Nicaragua, Panama, Peru and Venezuela . . . . . Gnamptogenys haenschi (in part)


 * In frontal view, mandibular dorsal surface costulate on basal fourth or less, the rest smooth and shiny; large eyes (OI>0.2); metacoxal dorsum with a lobe. Argentina, Brazil (BA, PA), Colombia, Costa Rica, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, Peru, USA (TX, LA) and Venezuela . . . . . Gnamptogenys hartmani (in part)

35
return to couplet #32
 * In dorsal view, propodeal dorsum mostly transversely striate (Fig. 9A) . . . . . 32


 * In dorsal view, propodeal dorsum mostly longitudinally striate or costulate (Fig. 9B) . . . . . 38

36
return to couplet #35
 * Head less elongate (CI>0.78); body brown to dark brown . . . . . 37


 * Head more elongate (CI<0.78); body black. Colombia, Costa Rica, Ecuador, Nicaragua and Panama. . . . . Gnamptogenys alfaroi

37
return to couplet #36
 * In dorsal view, mesosoma and petiole costulate; both propodeum and metacoxal dorsum edentate. Brazil (AM, PA, MT), Colombia, Ecuador and Peru . . . . . Gnamptogenys kempfi


 * In dorsal view, mesosoma and petiole finely striate; both propodeum and metacoxal dorsum dentate. Bolivia, Brazil (AC, AM, AP, BA, MT, PA, PR, RJ, RO, RR, SP), Colombia, Costa Rica, French Guiana, Ecuador, Guyana, Honduras, Nicaragua, Panama, Peru, Suriname and Venezuela . . . . . Gnamptogenys annulata

38
return to couplet #38
 * In frontal view, clypeal lamella laterally rounded, never angular (Fig. 10A); in lateral view, subpetiolar process usually rounded, rarely with a posterior tooth . . . . . 39


 * In frontal view, clypeal lamella with sharp lateral angles (Fig. 10B); in lateral view, subpetiolar process with a posterior tooth . . . . . 46

39
return to couplet #39
 * In frontal view, mandible triangular; in lateral view, metanotal groove absent. Argentina and Brazil (GO, PA, SP) . . . . . Gnamptogenys nana


 * In frontal view, mandible semitriangular to semifalcate; in lateral view, metanotal groove well-defined . . . . . 40

40
return to couplet #40
 * Metacoxal dorsum unarmed, at most with a low tubercle or swelling . . . . . 41


 * Metacoxal dorsum with a lobe or tooth . . . . . 43

41
return to couplet #41
 * In frontal view, clypeal lamella with a broad median concavity and laterally rounded; in ventral view, second gastral sternite sculptured; body costulate. Brazil (PR), Colombia, Costa Rica, French Guiana, Guatemala, Honduras, Jamaica, Mexico, Panama, Suriname and Venezuela . . . . . Gnamptogenys interrupta


 * In frontal view, clypeal lamella projecting medially, with a small median concavity, and laterally with blunt angles; in ventral view, second gastral sternite smooth and shiny, body striate or costulate . . . . . 42

42
return to couplet #41
 * In frontal view, head with fewer than 20 striae between frontal carina; in lateral view, base of pro, meso and metapleuron smooth and shiny; body costulate. Colombia, Costa Rica and Panama. . . . . Gnamptogenys andersoni


 * In frontal view, head with more than 30 striae between frontal carina; in lateral view, base of pro, meso and metapleuron with longitudinal striae; body striate. Colombia and Costa Rica . . . . . Gnamptogenys stellae

43
return to couplet #40
 * Metacoxal dorsum with a slender and parallel-sided lobe or tooth; HW>1.12 mm, WL>1.81 mm. Argentina, Brazil (AM, ES, GO, PA, PE, RJ, SP), Colombia, Costa Rica, Ecuador, French Guiana, Guyana, Honduras, Mexico, Nicaragua, Panama, Peru, Suriname, Trinidad and Tobago and Venezuela . . . . . Gnamptogenys mordax


 * Metacoxal dorsum with a low triangular lobe; HW<1.12 mm, WL<1.81 mm . . . . . 44

44
return to couplet #43
 * In lateral view, propodeal spiracle separated from declivity by less than its diameter. Brazil (BA) . . . . . Gnamptogenys wilsoni


 * In lateral view, propodeal spiracle separated from declivity by more than its diameter . . . . . 45

45
return to couplet #44
 * In frontal view, head dorsum striate (Fig. 11A). Bolivia and Peru . . . . . Gnamptogenys boliviensis


 * In frontal view, head dorsum costulate (Fig. 11B). Belize, Bolivia, Brazil (AM, BA, MG, PR, RJ, RR, SC, SE, SP), Colombia, Costa Rica, Ecuador, French Guiana, Guyana, Honduras, Mexico, Panama, Paraguay, Peru, Suriname and Venezuela . . . . . Gnamptogenys continua

46
return to couplet #38
 * Metanotal groove well-defined, visible in any angle; subpetiolar process without a posterior tooth . . . . . 47


 * Metanotal groove weakly defined, visible only in limited angles; subpetiolar process with posterior tooth . . . . . 48

47
return to couplet #46
 * In frontal view, anterior margin of clypeal lamella straight; metacoxal dorsum with a lobe. Brazil (BA, RJ, SC) . . . . . Gnamptogenys rimulosa


 * In frontal view, anterior margin of clypeal lamella with a bluntly angular concavity; metacoxal dorsum unarmed. Panama . . . . . Gnamptogenys biquetra

48
return to couplet #46
 * In dorsal view, propodeal declivity with longitudinal costulae that converge posteriorly; anterior face of petiolar node transversely costulate; mesometapleural suture absent or weakly impressed. Argentina, Bolivia, Brazil (widespread), Colombia, Costa Rica, Ecuador, French Guiana, Guyana, Lesser Antilles, Panama, Peru, Suriname, Trinidad and Tobago and Venezuela . . . . . Gnamptogenys horni


 * In dorsal view, propodeal declivity with parallel longitudinal costulae; most of anterior face of petiolar node longitudinally costulate, but frequently with a basal strip of transverse costulae that occasionally covers all of anterior face; mesometapleural suture well-impressed. Argentina, Brazil (widespread), Colombia, Costa Rica, Ecuador, French Guiana, Guyana, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Suriname and Venezuela . . . . . Gnamptogenys regularis

49
return to couplet #31
 * In frontal view, mandible falcate or semifalcate, with just the apex touching or overlapping the opposite mandible when totally closed (Fig. 12A) . . . . . 50


 * In frontal view, mandible triangular to elongate, with a fourth or more of the masticatory border overlapping the opposite mandible when closed (Fig. 12B) . . . . . 54

50
return to couplet #49
 * In lateral view, propodeal declivity with teeth or denticles; metacoxal dorsum with tooth; mostly continental species . . . . . 50


 * In lateral view, propodeal declivity rounded, without teeth or denticles; metacoxal dorsum unarmed; endemic to Hispaniola (see also third lug) . . . . . 53


 * In lateral view, propodeal declivity with teeth or denticles; metacoxal dorsum unarmed; endemic to Cuba . . . . . Gnamptogenys rumba

51
return to couplet #50
 * In frontal view, mandible with short triangular tooth on basal internal margin . . . . . 52


 * In frontal view, mandible with a lobe or broad convexity on basal internal margin. Brazil (AC, AL, AM, BA, CE, MG, PA, RJ) and Ecuador . . . . . Gnamptogenys mediatrix

52
return to couplet #51
 * In frontal view, clypeus with a lobe anterior to each antennal fossa, each lobe partially covering the clypeal lamella; in lateral view, mesonotal spiracle in depression below level of surrounding integument. Ecuador . . . . . Gnamptogenys laticephala


 * In frontal view, clypeus without lobes between antennal fossae and lamella; in lateral view, mesonotal spiracle at same level as surrounding integument. Colombia, Costa Rica, Ecuador, Panama and Nicaragua . . . . . Gnamptogenys banksi

53
return to couplet #50
 * In frontal view, mandible elongate and slender; propodeal dorsal surface with smooth transverse costulae. Hispaniola . . . . . Gnamptogenys schmitti


 * In frontal view, mandible shorter and thicker; propodeal dorsal surface with vermiculate longitudinal costulae. Hispaniola . . . . . Gnamptogenys semiferox

54
return to couplet #49
 * In frontal view, mandibular dorsal surface mostly smooth and shiny, sometimes with striae or costulae extending to basal third; mesosomal dorsum usually without transverse sutures, if otherwise, then the ant is ferruginous and finely striate . . . . . 55


 * In frontal view, mandibular dorsal surface mostly striate or rugulose; metanotal groove well-impressed . . . . . 68

55
return to couplet #54
 * Very large species (HW≥1.4 mm; WL≥2.3 mm) . . . . . 56


 * Smaller species (HW<1.4 mm; WL<2.3 mm) . . . . . 57

56
return to couplet #55
 * In dorsal view, mesosoma costulate; metacoxa with dorsal tooth; in lateral view, apex of petiolar node ending in a blunt angle; body black. Brazil (AC, AM, PA, RO, RR), Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname and Venezuela . . . . . Gnamptogenys tortuolosa


 * In dorsal view, mesosoma striate; metacoxal dorsum unarmed; in lateral view, apex of petiolar node ending in a blunt point; body ferruginous. Bolivia, Brazil (AC, AM, AP, BA, MT, PA, RO), Colombia, Costa Rica, Ecuador, French Guiana, Panama, Peru and Venezuela . . . . . Gnamptogenys concinna

57
return to couplet #55
 * In dorsal view, mesosoma striate; transverse crest, distinct from mesosomal striae, separating the propodeal dorsum from the propodeal declivity (Fig. 13A) . . . . . 58


 * In dorsal view, mesosoma costulate; propodeal declivity and propodeal dorsum not separated by crest distinct from mesosomal striae (Fig. 13B) . . . . . 59

58
return to couplet #57
 * Posterior face of petiolar node longitudinally costulate. Argentina, Brazil (BA, PA), Colombia, Costa Rica, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, Peru, USA (TX, LA) and Venezuela . . . . . Gnamptogenys hartmani (in part)


 * Posterior face of petiolar node transversely costulate. Argentina, Brazil (BA, RR, RS, SP) and Paraguay . . . . . Gnamptogenys bruchi

59
return to couplet #57
 * Posterior face of petiolar node longitudinally costulate . . . . . 60


 * Posterior face of petiolar node transversely costulate . . . . . 64

60
return to couplet #59
 * In frontal view, clypeal lamella laterally angular; mandible elongate, the basal and masticatory margins separated by a broad convexity . . . . . 61
 * In frontal view, clypeal lamella laterally rounded; mandible triangular, the basal and masticatory margins separated by an angle . . . . . 63

61
return to couplet #60
 * In lateral view, petiolar node with a pointed apex; propodeal declivity longitudinally costulate; body uniformly brown. Bolivia, Brazil (widespread), Colombia, Costa Rica, French Guiana, Ecuador, Guyana, Panama, Peru, Suriname and Venezuela . . . . . Gnamptogenys acuminata


 * In lateral view, petiolar node sometimes with a posterior projection but never pointed; propodeal declivity usually transversely costulate, rarely longitudinal; color variable, usually with both brown and ferruginous parts, rarely totally brown . . . . . 62

62
return to couplet #61
 * Metacoxal teeth absent or vestigial; in lateral view, propodeal declivity without lateral lobes; body dark brown to bicolored. Argentina, Belize, Bolivia, Brazil (widespread), Colombia, Costa Rica, Ecuador, El Salvador, French Guiana, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Suriname and Venezuela . . . . . Gnamptogenys sulcata


 * Small metacoxal teeth present; in lateral view, propodeum with small lateral lobes; body yellow. Bolivia . . . . . Gnamptogenys flava

63
return to couplet #60
 * In frontal view, clypeal lamella with two convexities; metacoxal dorsum with a lobe; in lateral view, petiolar node with dorsal and posterior margins forming approximately a right angle. Panama . . . . . Gnamptogenys transversa


 * In frontal view, clypeal lamella with a single convexity; metacoxal dorsum unarmed; in lateral view, petiolar node with an apical point that overhangs the posterior margin. Brazil (AM, PA), Colombia, Ecuador, Peru and Venezuela . . . . . Gnamptogenys fernandezi

64
return to couplet #59
 * In frontal view, clypeal lamella laterally sharply angular . . . . . 65


 * In frontal view, clypeal lamella laterally rounded or obtusely angular . . . . . 66

65
return to couplet #64
 * HW<1.1 mm; WL<1.7 mm; in frontal view, clypeal lamella with a straight anterior margin. Bolivia, Brazil (AC, RO, MG), Colombia, French Guiana, Guyana and Venezuela . . . . . Gnamptogenys ericae


 * HW>1.1 mm; WL>1.7 mm; in frontal view, clypeal lamella medially convex, laterally concave. Brazil (AM, RR), Colombia, Panama and Venezuela . . . . . Gnamptogenys curvoclypeata

66
return to couplet #64
 * In frontal view, clypeal lamella straight medially and rounded laterally; mandible semitriangular, the basal and masticatory margins separated by a broad convexity; propodeal declivity longitudinally costulate . . . . . 67


 * In frontal view, clypeal lamella medially concave and convex laterally; mandible triangular, the basal and masticatory margins separated by an angle; propodeal declivity transversely costulate. Costa Rica . . . . . Gnamptogenys volcano

67
return to couplet #66
 * In lateral view, petiolar node with a more or less convex dorsal margin; metacoxal dorsum with an acute tooth; subpetiolar process with sharp angles. Brazil (BA, MG, PR, RJ, SC, SP) . . . . . Gnamptogenys lucaris


 * In lateral view, petiolar node with a straight dorsal margin; metacoxal dorsum with a triangular tooth; subpetiolar process with blunt angles. . . . . . Gnamptogenys siapensis

68
return to couplet #54
 * Scape usually smooth and shiny with sparse punctulae (Fig. 14A) . . . . . 69


 * Scape rugulose or striate (sculpture sometimes attenuated) (Fig. 14B) . . . . . 75

69
return to couplet #68
 * Mandibular dorsal surface striate or rugulose; metacoxal dorsum toothed . . . . . 70


 * Mandibular dorsal surface smooth and shiny; metacoxal dorsum unarmed. Hispaniola . . . . . Gnamptogenys insularis

70
return to couplet #69
 * Masticatory margin of mandible with distinct denticles . . . . . 71


 * Masticatory margin of mandible edentate or with indistinct denticulation . . . . . 72

71
return to couplet #70
 * In lateral view, propodeum unarmed; body striate. Brazil (AM, CE, RR), Hispaniola and Lesser Antilles . . . . . Gnamptogenys lineolata


 * In lateral view, propodeum with denticles; body costulate. Colombia . . . . . Gnamptogenys ingeborgae

72
return to couplet #70
 * In frontal view, scape surpasses vertex by at least twice apical width of scape; HW>1.1 mm; WL>1.6 mm . . . . . 73


 * In frontal view, scape surpasses vertex by not more than apical width of scape; HW<1.1 mm; WL<1.6 mm. Argentina, Bolivia, Brazil (AL, BA, PR, RJ, RS, SC, SP), Paraguay and Peru. . . . . Gnamptogenys rastrata

73
return to couplet #72
 * In dorsal view, petiolar node shorter than wide. Brazil (AP, PA), Colombia and Ecuador . . . . . Gnamptogenys lanei


 * In dorsal view, petiolar node longer than wide . . . . . 74

74
return to couplet #73
 * In lateral view, propodeal tooth longer than diameter of propodeal spiracle; subpetiolar process projecting anteriorly as a triangular lobe. Brazil (PA), Colombia and French Guiana . . . . . Gnamptogenys enodis (in part)


 * In lateral view, propodeal tooth shorter than diameter of propodeal spiracle; subpetiolar process subquadrate. Brazil (BA, ES, MG, PA, PR, RJ, RS, SP) and Colombia . . . . . Gnamptogenys menozzii

75
return to couplet #68
 * Propodeal teeth absent. Argentina, Bolivia, Brazil (AC, AM, BA, GO, MG, MS, PA, RO, SP), Colombia, Costa Rica, Ecuador, French Guiana, Nicaragua, Panama, Peru and Venezuela . . . . . Gnamptogenys haenschi (in part)


 * Propodeal teeth present . . . . . 76

76
return to couplet #75
 * In frontal view, eyes not prominent nor protruding, relatively flat; in dorsal view, anterior pronotal margin with longitudinal costulae. Argentina, Bolivia, Brazil (AC, AM, ES, GO, MT, PA, PR, SC, SP), Colombia, Costa Rica, Ecuador, French Guiana, Guyana, Panama, Peru, Suriname, Uruguay, USA (exotic in FL, AL, MS, TX) and Venezuela . . . . . Gnamptogenys triangularis


 * In frontal view, eyes prominent and protruding; in dorsal view, anterior pronotal margin with at least 5 transverse rugulae or costulae . . . . . 77

77
return to couplet #76
 * In dorsal view, vertex with 4–5 transverse costulae; anterior half of first gastral tergite rugose . . . . . 78


 * In dorsal view, vertex longitudinally costulate; anterior half of first gastral tergite longitudinally costulate . . . . . 79

78
return to couplet #77
 * In lateral view, propodeal teeth at least as long as the distance between their bases; body ferruginous. Colombia, Costa Rica and Panama . . . . . Gnamptogenys bispinosa


 * In lateral view, propodeal teeth short; body black. Brazil (PA), Colombia and Ecuador . . . . . Gnamptogenys perspicax

79
return to couplet #77
 * Dorsal face of propodeum transversely costulate. Costa Rica and Panama . . . . . Gnamptogenys cuneiforma


 * Dorsal face of propodeum longitudinally costulate . . . . . 80

80
return to couplet #79
 * In dorsal view, pronotum longitudinally costulate; in lateral view, subpetiolar process rectangular. Bolivia, Brazil (AM, PA), Colombia, Costa Rica, Ecuador, French Guiana, Guatemala, Nicaragua and Panama . . . . . Gnamptogenys mecotyle


 * In dorsal view, pronotum with anterior strip of transverse costulae; in lateral view, subpetiolar process a modest lobe, without angles. Brazil (PA), Colombia and French Guiana . . . . . Gnamptogenys enodis (in part)