Key to New World Gnamptogenys workers

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This worker key is based on: 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 (doi:10.11646/zootaxa.4747.3.2). 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
Figure 1. Dorsal view of mesosoma, showing: A) promesonotal suture well marked, totally interrupting dorsal mesosomal sculputure (Gnamptogenys pleurodon-CASENT0281219); B) promesonotal suture well impressed, but not interrupting dorsal mesosomal sculpture (Gnamptogenys mediatrix-CASENT0281839); and C) promesonotal suture absent (Gnamptogenys minuta-CASENT0281213). Photos by Estella Ortega (A, C) and Shannon Hartmann (B).
  • 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 . . . . . 81

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
Figure 2. Dorsal view of mesosoma, showing: A) mesosomal dorsum completely sculptured (Gnamptogenys avus-USNMENT00413910); and B) mesosomal dorsum with smooth and shiny areas (Gnamptogenys relicta-USNMENT00412058). Photos by Jeffrey Sosa-Calvo.
  • 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
Head of Gnamptogenys haytiana worker
Profile of Gnamptogenys haytiana worker
  • 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
Head of Gnamptogenys avus worker
Profile of Gnamptogenys avus worker
  • 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
Head of Gnamptogenys mina worker
Profile of Gnamptogenys mina worker

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
Head of Gnamptogenys lavra worker
Profile of Gnamptogenys lavra worker
  • 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
Head of Gnamptogenys lenis worker
Profile of Gnamptogenys lenis worker

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
Head of Gnamptogenys relicta worker
Profile of Gnamptogenys relicta worker
  • 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
Figure 3. Dorsal view of mesosoma, showing: A) promesonotal suture (1) and metanotal groove (2) (Gnamptogenys bisulca- CASENT0281521); and B) only promesonotal suture (1) (Gnamptogenys moelleri-CASENT0246692). Photos by Zach Lieberman (A) and Andrea Walker (B).

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
Head of Gnamptogenys bisulca worker
Profile of Gnamptogenys bisulca worker
  • In dorsal view, area between promesonotal suture and metanotal groove wide and ovaloid; anterior mesonotal margin forms a blunt angle. Colombia . . . . . Gnamptogenys dichotoma
Head of Gnamptogenys dichotoma worker
Profile of Gnamptogenys dichotoma worker

13

return to couplet #11

  • In frontal view, anterior margin of clypeal lamella bluntly angular; in dorsal view, vertex longitudinally costulate. Colombia . . . . . Gnamptogenys brunnea
Head of Gnamptogenys brunnea worker
Profile of Gnamptogenys brunnea worker
  • 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
Head of Gnamptogenys auricula worker
Profile of Gnamptogenys auricula worker

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
Figure 4. Lateral view of petiole, showing: A) anterior and dorsal margins of petiole separated by blunt angles (Gnamptogenys striatula-CASENT0106042); B, C) anterodorsal margin of petiole curved, no angle separating dorsal and anterior margins (Gnamptogenys porcata-CASENT0281222, Gnamptogenys strigata-CASENT0217487). Photos by Michael Branstetter (A), Estella Ortega (B) and Will Ericson (C).
  • 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
Head of Gnamptogenys moelleri worker
Profile of Gnamptogenys moelleri worker
  • 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
Profile of Gnamptogenys pernambucana worker
  • 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
Head of Gnamptogenys striatula worker
Profile of Gnamptogenys striatula worker
  • 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
Head of Gnamptogenys ammophila worker
Profile of Gnamptogenys ammophila worker

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
Figure 5. Lateral view of petiole, showing: A) apex of petiolar node overhanging the posterior margin (Gnamptogenys porcata-CASENT0281222); and B) petiolar node apex not overhanging the posterior margin (Gnamptogenys pittieri-CASENT0281218). Photos by Estella Ortega.
  • 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
Head of Gnamptogenys acuta worker
Profile of Gnamptogenys acuta worker
  • 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
Head of Gnamptogenys gracilis worker
Profile of Gnamptogenys gracilis worker
Figure 6. Dorsal view of head, showing A) transverse costulae extending across the width of the vertex (Gnamptogenys gracilis- CASENT0281525); B) vertex without transverse costulae (Gnamptogenys illimani-CASENT0179988); C) transverse costulae limited to the center of the vertex (Gnamptogenys pittieri-CASENT0281218); and D) transverse costulae not extending all across the vertex (Gnamptogenys porcata-CASENT0281222). Photos by Zach Lieberman (A), Erin Prado (B) and Estella Ortega (C, D).
  • 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
Head of Gnamptogenys pilosa worker
Profile of Gnamptogenys pilosa worker
  • 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
Head of Gnamptogenys ejuncida worker
Profile of Gnamptogenys ejuncida worker
  • 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
Head of Gnamptogenys porcata worker
Profile of Gnamptogenys porcata worker

24

return to couplet #21

  • Scape and tibia with one or no semierect or semidecumbent hairs. Colombia and Ecuador . . . . . Gnamptogenys extra
Head of Gnamptogenys extra worker
Profile of Gnamptogenys extra worker

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
Head of Gnamptogenys pleurodon worker
Profile of Gnamptogenys pleurodon worker
  • 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
Profile of Gnamptogenys nigrivitrea worker

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
Head of Gnamptogenys pittieri worker
Profile of Gnamptogenys pittieri worker
  • 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

Head of Gnamptogenys ilimani worker
Profile of Gnamptogenys ilimani worker
  • 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
Head of Gnamptogenys aspera worker
Profile of Gnamptogenys aspera worker


  • In lateral view, subpetiolar process with a well-developed fenestra. Colombia and Ecuador. . . . . Gnamptogenys andina
Head of Gnamptogenys andina worker
Profile of Gnamptogenys andina worker

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
Head of Gnamptogenys strigata worker
Profile of Gnamptogenys strigata worker
  • 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
Profile of Gnamptogenys latistriata worker

31

return to couplet #1

  • In frontal view, scape not reaching the vertex margin (Fig. 7A) . . . . . 32
Figure 7. Frontal view of head, showing: A) scape not reaching vertex margin (Gnamptogenys interrupta-CASENT0178679); B) scape surpassing vertex margin by at least one apical width (Gnamptogenys tortuolosa-CASENT0907192). Photos by April Nobile (A) and Will Ericson (B).
  • 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
Figure 8. Frontal view of mandibles, showing: A) mandibular dorsum striated (Gnamptogenys haenschi-CASENT0281527); and B) mandibular dorsum smooth and shiny (Gnamptogenys annulata-CASENT0281514). Photos by Zach Lieberman.
  • 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
Head of Gnamptogenys falcaria queen
Profile of Gnamptogenys falcaria queen
  • 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)
Head of Gnamptogenys haenschi worker
Profile of Gnamptogenys haenschi worker
  • 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
Figure 9. Dorsal view of mesosoma, showing: A) propodeum dorsum transversely striate (Gnamptogenys annulata-CASENT0217480); and B) propodeum dorsum longitudinally striate (Gnamptogenys stellae-CASENT0281227). Photos by Will Ericson (A) and Estella Ortega (B).
  • 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
Head of Gnamptogenys alfaroi worker
Profile of Gnamptogenys alfaroi worker

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
Head of Gnamptogenys kempfi worker
Profile of Gnamptogenys kempfi worker
  • 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
Head of Gnamptogenys annulata worker
Profile of Gnamptogenys annulata worker

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
Figure 10. Frontal view of head, showing: A) clypeal lamella laterally rounded (Gnamptogenys stellae-CASENT0281227); and B) clypeal lamella with sharp lateral angles (Gnamptogenys regularis-CASTYPE00616). Photos by Estella Ortega (A) and April Nobile (B).
  • 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
Head of Gnamptogenys nana worker
Profile of Gnamptogenys nana worker


  • 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

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
Profile of Gnamptogenys interrupta worker
  • 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
Head of Gnamptogenys andersoni worker
Profile of Gnamptogenys andersoni worker
  • 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
Head of Gnamptogenys stellae worker
Profile of Gnamptogenys stellae worker

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
Head of Gnamptogenys mordax worker
Profile of Gnamptogenys mordax worker
  • 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
Head of Gnamptogenys wilsoni worker
Profile of Gnamptogenys wilsoni worker
  • In lateral view, propodeal spiracle separated from declivity by more than its diameter . . . . . 45

45

return to couplet #44

Figure 11. Frontal view of head, showing: A) head dorsum striate (Gnamptogenys boliviensis- CASENT0900556); and B) head dorsum costulate (Gnamptogenys continua-CASENT0178676). Photos by Ryan Perry (A) and April Nobile (B).
Profile of Gnamptogenys boliviensis worker
  • 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
Head of Gnamptogenys continua worker
Profile of Gnamptogenys continua worker

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
Head of Gnamptogenys horni worker
Profile of Gnamptogenys horni worker
  • 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
Head of Gnamptogenys regularis worker
Profile of Gnamptogenys regularis worker

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
Figure 12. Frontal view of head, showing: A) falcate mandible (Gnamptogenys rumba-CASENT0179954); and B) semitriangular mandible (Gnamptogenys tortuolosa-ECOFOG-IT14-0450-23). Photos by Erin Prado (A) and Marta Soltysiak (B).
  • 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
Head of Gnamptogenys rumba worker
Profile of Gnamptogenys rumba worker

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
Head of Gnamptogenys mediatrix worker
Profile of Gnamptogenys mediatrix worker

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
Head of Gnamptogenys banksi worker
Profile of Gnamptogenys banksi worker

53

return to couplet #50

  • In frontal view, mandible elongate and slender; propodeal dorsal surface with smooth transverse costulae. Hispaniola . . . . . Gnamptogenys schmitti
Head of Gnamptogenys schmitti worker
Profile of Gnamptogenys schmitti worker
  • In frontal view, mandible shorter and thicker; propodeal dorsal surface with vermiculate longitudinal costulae. Hispaniola . . . . . Gnamptogenys semiferox
Head of Gnamptogenys semiferox worker
Profile of Gnamptogenys semiferox worker

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

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
Profile of Gnamptogenys tortuolosa worker
  • 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
Head of Gnamptogenys concinna worker
Profile of Gnamptogenys concinna worker

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
Figure 13. Dorsal view of mesosoma, showing: A) propodeal dorsum separated from propodeal declivity by a transverse crest (Gnamptogenys bruchi-CASENT0173382); and B) propodeal dorsum and declivity without crest (Gnamptogenys acuminata-CASENT0281511). Photos by April Nobile (A) and Zach Lieberman (B).
  • 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
Head of Gnamptogenys bruchi worker
Profile of Gnamptogenys bruchi worker

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
Head of Gnamptogenys acuminata worker
Profile of Gnamptogenys acuminata worker
  • 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
Head of Gnamptogenys sulcata worker
Profile of Gnamptogenys sulcata worker
  • 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
Profile of Gnamptogenys transversa worker
  • 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
Profile of Gnamptogenys fernandezi worker

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
Head of Gnamptogenys ericae worker
Profile of Gnamptogenys ericae worker
  • 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
Profile of Gnamptogenys curvoclypeata worker

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
Head of Gnamptogenys volcano worker
Profile of Gnamptogenys volcano worker

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
Head of Gnamptogenys siapensis worker
Profile of Gnamptogenys siapensis worker

68

return to couplet #54

  • Scape usually smooth and shiny with sparse punctulae (Fig. 14A) . . . . . 69
Figure 14. Frontal view of head, showing: A) scape smooth and shiny (Gnamptogenys rastrata-CASENT0281223); and B) scape with sparse sculpture (Gnamptogenys haenschi-CASENT0179994). Photos by Estella Ortega (A) and Erin Prado (B).
  • 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
Head of Gnamptogenys insularis worker
Profile of Gnamptogenys insularis worker

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
Head of Gnamptogenys lineolata worker
Profile of Gnamptogenys lineolata worker
Profile of Gnamptogenys ingeborgae worker

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
Head of Gnamptogenys rastrata worker
Profile of Gnamptogenys rastrata worker

73

return to couplet #72

  • In dorsal view, petiolar node shorter than wide. Brazil (AP, PA), Colombia and Ecuador . . . . . Gnamptogenys lanei
Head of Gnamptogenys lanei worker
Profile of Gnamptogenys lanei worker

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)
Head of Gnamptogenys enodis worker
Profile of Gnamptogenys enodis worker
  • 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
Head of Gnamptogenys menozzii worker
Profile of Gnamptogenys menozzii worker

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)
Head of Gnamptogenys haenschi worker
Profile of Gnamptogenys haenschi worker

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
Profile of Gnamptogenys triangularis worker
  • 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
Head of Gnamptogenys bispinosa worker
Profile of Gnamptogenys bispinosa worker
  • In lateral view, propodeal teeth short; body black. Brazil (PA), Colombia and Ecuador . . . . . Gnamptogenys perspicax
Head of Gnamptogenys perspicax worker
Profile of Gnamptogenys perspicax worker

79

return to couplet #77

Profile of Gnamptogenys cuneiforma worker
  • 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
Head of Gnamptogenys mecotyle worker
Profile of Gnamptogenys mecotyle worker
  • 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)
Head of Gnamptogenys enodis worker
Profile of Gnamptogenys enodis worker

81

return to couplet #1

82

return to couplet #81

  • Integument mostly opaque, sculpturing predominantly granulose with variable degrees of areolae/foveolae (Fig. 15A) . . . . . 83
Figure 15. Frontal view of head, showing: A) integument opaque with granulose sculpturing (Gnamptogenys fieldi-CASENT0178675); and B) integument smooth and shiny, foveolate (Gnamptogenys simulans-CASENT0281522). Photos by April Nobile (A) and Zach Lieberman (B).
  • Integument mostly shiny or silky, sculpturing can be finely striolate or smooth with variable degrees of areolae/foveolae (Fig. 15B) . . . . . 85

83

return to couplet #81

  • In frontal view, mandible falcate, masticatory margin edentate and concave. Venezuela . . . . . Gnamptogenys fieldi
Head of Gnamptogenys fieldi worker
Profile of Gnamptogenys fieldi worker
  • In frontal view, mandible triangular, masticatory margin fairly straight and denticulate or crenulate . . . . . 84

84

return to couplet #83

  • In lateral view, metanotal groove well-impressed; propodeum and petiole spiracles shiny and conspicuous. Venezuela . . . . . Gnamptogenys petiscapa
Head of Gnamptogenys petiscapa worker
Profile of Gnamptogenys petiscapa worker
  • In lateral view, metanotal groove absent; propodeum and petiole spiracles opaque and not conspicuous. Belize, Bolivia, Brazil (widespread), Colombia, Costa Rica, Ecuador, French Guiana, Guatemala, Guyana, Mexico, Nicaragua, Panama, Peru, Suriname and Venezuela . . . . . Gnamptogenys minuta
Head of Gnamptogenys minuta worker
Profile of Gnamptogenys minuta worker

85

return to couplet #82 Mandible falcate. Brazil (AC), Colombia, Ecuador, Peru and Venezuela . . . . . Gnamptogenys falcifera

Head of Gnamptogenys falcifera worker
Profile of Gnamptogenys falcifera worker

- Mandible triangular . . . . . 86

86

return to couplet #85

  • In frontal view, eyes not prominent, broadly convex; anterior clypeal margin broadly convex; occipital lobe rounded. Costa Rica, Ecuador, Guatemala, Honduras, Mexico, Nicaragua and Panama . . . . . Gnamptogenys simulans
Head of Gnamptogenys simulans worker
Profile of Gnamptogenys simulans worker
  • In frontal view, eyes prominent, semispherical; anterior clypeal margin medially concave; occipital lobe sub-angular. Brazil (MT) and . . . . . Gnamptogenys vriesi
Head of Gnamptogenys vriesi worker
Profile of Gnamptogenys vriesi worker

87

return to couplet #81

  • Meso and metatibial spurs absent. Argentina, Brazil (MA, MG, PA, PR, RO), Colombia, Paraguay and Venezuela . . . . . Gnamptogenys caelata
Head of Gnamptogenys caelata worker
Profile of Gnamptogenys caelata worker

88

return to couplet #87

  • In frontal view, clypeal lamella present; clypeus with a median tooth. Brazil (BA, MG, SC) . . . . . Gnamptogenys striolata
Head of Gnamptogenys striolata worker
Profile of Gnamptogenys striolata worker
  • In frontal view, clypeal lamella absent; clypeus with a median lobe. Brazil (RJ) . . . . . Gnamptogenys piei
Head of Gnamptogenys xxx piei
Profile of Gnamptogenys xxx piei

Notes

An earlier key, replaced by the above, is found in: Lattke, J.E., Fernández, F. & Palacio, E.E. 2007. Identification of the species of Gnamptogenys Roger in the Americas (pp. 254-270). In Snelling, R.R., Fisher, B.L. & Ward, P.S. (eds). Advances in ant systematics: homage to E.O. Wilson – 50 years of contributions. Memoirs of the American Entomological Institute 80: 690 pp

This key was added to Antwiki in 2014. It is obsolete but can still be found here: Key to New World Gnamptogenys Species.