Key to Micronesian Ants

This worker key is based on: Clouse, R. M. 2007. The Ants (Hymenoptera: Formicidae) of Micronesia. Micronesica. 39(2): 171–296.

1

Body with two isolated segments (the petiole and postpetiole) between mesosoma and gaster (Fig. 1C) . . . . . 2

Body with one isolated segment between mesosoma and gaster (the petiole), its separation from the gaster being a narrow constriction (Fig. 1A–B) . . . . . 3

Body with one isolated segment between mesosoma and gaster that is broadly attached to the first segment of the gaster (Fig. 9B) (Amblyoponinae) . . . . . 66

2

return to couplet #1

Frontal carinae close and vertical, such that antennal insertions are completely visible from above; pygydium flattened and bordered by tiny denticles (Fig. 3B–C) (Cerapachyinae) . . . . . 4

Frontal carinae usually covering antennal insertions such that they are at most only partly visible from above; pygydium simple (Myrmicinae) . . . . . 5

3

return to couplet #1

Sting present (Ponerinae) . . . . . 67

Sting absent . . . . . 85

4

return to couplet #2

With prominent eyes (Fig. 3B) . . . . . Cerapachys sp. 91952

Without eyes . . . . . Ooceraea biroi

5

return to couplet #2

Antennae with 7 or fewer segments . . . . . 6

Antennae with more than 7 segments . . . . . 14

6

return to couplet #5

Antennae with 7 segments (Fig. 1C) . . . . . Eurhopalothrix procera

Antennae with 6 or fewer segments . . . . . 7

7

return to couplet #6

Mandibles compact and triangular; labial shield without extended lateral margins (never T-shaped); inner margins of mandibles lined with teeth (Fig. 11B) . . . . . 8

Mandibles long and thin; labial shield with extended lateral margins, making the whole sclerite T-shaped; teeth only at ends of the mandibles (Fig. 11C) . . . . . 9

8

return to couplet #7

Eyes present; head with a single, long hair projecting laterally from each side, immediately above end of the antennal scrobe (Fig. 11A) . . . . . Strumigenys karawajewi

Eyes tiny, almost completely missing; head without single, distinct hair projecting laterally from each side . . . . . Strumigenys membranifera

9

return to couplet #7

Antennae with 4 segments . . . . . Strumigenys emmae

Antennae with 6 segments . . . . . 10

10

return to couplet #9

When view from above, mandibles with 3 apical teeth, the middle one shorter than other two (Fig. 11C) . . . . . Strumigenys rogeri

Mandibles with 2 apical teeth . . . . . 11

11

return to couplet #10

Posterior propodeum to anterior gaster covered with a light-colored,

spongy substance (Fig. 11D) . . . . . 12

Without spongy material (Fig. 11E) . . . . . Strumigenys szalayi

12

return to couplet #11

Combining the following: Mesosoma with little or no sponge, most sponge concentrated on the ventral side of the petiolar node and postpetiole; conspicuous standing hairs on the mesonotum consisting of a short pair on the pronotum and mesonotum . . . . . Strumigenys mayri

Not as above . . . . . 13

13

return to couplet #12

HL around 0.7 mm; curved, erect hairs on head long and spaced about as far apart as their length; spongiform bodies on propodeum forming two distinct ridges from the propodeal spines down to the petiolar insertion; the inner margin of the mandibles straight, base of subapical tooth joining base of end tooth, with no straight section of mandible separating the two (Fig. 11E) . . . . . Strumigenys godeffroyi

HL usually less than 0.5 mm; curved, erect hairs on head spaced closer together than their length; two pairs of extremely long hairs often missing; spongiform bodies on propodeum disorganized and not covering propodeal spines; inner margin of mandibles continuously curved, the subapical tooth separated from the base of the end tooth by a section of mandible longer than the subapical tooth’s length . . . . . Strumigenys frivaldszkyi

14

return to couplet #5

Postpetiole attached to dorsal surface of the gaster; small yellow ants . . . . . 15

Postpetiole attached to anterior end of the gaster, the gaster not noticeably suspended below the postpetiole; size and color variable . . . . . 16

15

return to couplet #14

Dorsal edge of each propodeal spine with a stout hair (Fig. 3D) . . . . . Crematogaster biroi cf.

Dorsal edge of each propodeal spine without a stout hair (Fig. 3E) . . . . . Crematogaster fritzi

16

return to couplet #14

Pronotum, mesonotum, and propodeum each bearing a pair of long spines; workers distinctly dimorphic . . . . . Pheidole sexspinosa

Lacking spines on the mesosoma as described above; workers monomorphic, polymorphic, or dimorphic . . . . . 17

17

return to couplet #16

Body surfaces, except for tarsi, funiculi, and mandibles covered with evenly spaced paddle-like hairs; antennae 12-segmented . . . . . Calyptomyrmex

Paddle-shaped hairs usually absent, or, if present, not covering all body surfaces as described above; antennal segment number variable . . . . . 18

18

return to couplet #17

Large, plate-like keel on the ventral surface of petiole; propodeum without spines (Fig. 15D) . . . . . 19

Ventral petiole without a large, plate-like keel; propodeum often with spines or blunt projections . . . . . 24

19

return to couplet #18

HW and HL more than 0.65 mm (up to 0.875 mm) . . . . . 20

HW 0.37–0.55 mm, HL 0.47–0.62 mm . . . . . 21

20

return to couplet #19

Head and mesosoma covered with thick, smooth, wavy, striate sculpture, giving a wrinkled appearance; HW 0.68 mm; HL 0.76 mm (Fig. 15A) . . . . . Vollenhovia mwereka

Head and mesosoma not sculptured as above (not wrinkled in appearance and with smooth patches on dorsum); head square in front view, both HW and HL about 0.8 mm . . . . . Vollenhovia oblonga

21

return to couplet #19

Area behind eyes distincly striate (Fig. 14C); middle part of frons punctate; HW 0.42–0.45 mm; HL 0.52–0.55 mm, CI = 81–86 (Fig. 14D) . . . . . 22

Area behind eyes smooth (Fig. 15C); middle part of fronts striate or smooth; head either smaller (and usually narrower) or larger and more square . . . . . 23

22

return to couplet #22

Mesosoma completely punctate (Fig. 15D); body dark brown . . . . . Vollenhovia kaselela

Central propodeal dorsum and anterior pronotum with smooth patches; body orangish brown . . . . . Vollenhovia sp. 6041940

23

return to couplet #21

Antennae 11-segmented; HW 0.37–0.41 mm (Fig. 15B); mesosoma mostly punctate, except for smooth patch on central anterior pronotum . . . . . Vollenhovia pwidikidika

Antennae 12-segmented; HW 0.55 mm (Fig. 14B); Mesosoma with smooth areas on dorsal and lateral propodeum and promesonotum . . . . . Vollenhovia sp. 23031948

24

return to couplet #18

Head with a prominent carina on each side that runs below eye from base of the mandibles to posterior corner of the head (Fig. 5C–D) . . . . . Myrmecina sp. 7121952

Head without such a carina . . . . . 25

25

return to couplet #24

Antennae with 10 segments, with the last 2 forming a conspicuous club . . . . . 26

Antennae with 9, 11 or 12 segments . . . . . 27

26

return to couplet #25

Eyes tiny; area around propodeal spiracle shining; workers monomorphic . . . . . Solenopsis papuana

Maximum eye diameter about equal to antennal club width; area around propodeal spiracle dull in larger workers; workers polymorphic . . . . . Solenopsis geminata

27

return to couplet #25

Clypeus forming a flange or shelf above the mandibles . . . . . 28

Clypeus completing the overall curve of the head to the mouth . . . . . 33

28

return to couplet #27

Mesosoma sculptured but lacking teeth, corners, or spines; anterior clypeal border extended forward as a distinctive, narrow, rectangular lobe; antennal scrobes large and deep, partly concealed by broad, downwardly-curving frontal carinae . . . . . Metapone truki

Mesosoma glossy and with teeth, corners, or spines; clypeus projecting outward to form an acutely cornered shelf above the mandibles; antennal scrobes shallow, not concealed by carinae (Fig. 10A–C) . . . . . 29

29

return to couplet #28

Head and mesosoma with strong, coarse, reticulate sculpture; propodeal spines as long as the petiole . . . . . Pristomyrmex punctatus

Reticulate sculpture absent and propodeal spines shorter than the petiole . . . . . 30

30

return to couplet #29

Sharp teeth on the pronotum . . . . . 31

Sharp pronotal teeth absent . . . . . 32

31

return to couplet #30

Pronotal spines nearly as large as the propodeal spines and clearly projecting upwards above the dorsal surface in side view (Fig. 10C) . . . . . Pristomyrmex quadridens

Pronotal spines notably shorter than the propodeal spines and projecting laterally, often not altering the outline of dorsal pronotum in side view . . . . . Pristomyrmex minusculus

32

return to couplet #30

Propodeal spines only about half length of postpetiole; deep, well-defined pits on head, especially laterally between eyes and mandibles; dark brown species (Fig. 10B) . . . . . Pristomyrmex levigatus

Propodeal spines about as long as length of postpetiole; head with shallow pits only; orange species (Fig. 10A) . . . . . Pristomyrmex largus

33

return to couplet #27

Antennal insertions in deep pit, the walls of which are formed by the fused rear clypeus and frontal lobes (Figs. 12B, 12D, 13B, 14A) . . . . . 34

Antennal insertions not in deep pit . . . . . 41

34

return to couplet #33

Antennae 11-segmented . . . . . 35

Antennae 12-segmented . . . . . 36

35

return to couplet #34

Head and mesosoma with distinct, widely spaced, longitudinal and loosely reticulate sculpturing; frons and most of head with longitudinal sculpturing only; petiolar node smooth, shiny, and nearly square in profile

(Fig. 12B) . . . . . Tetramorium sp. 14121952

Mesosoma with deep reticulate sculpturing, head with reticulate sculpturing at vertex; petiolar node sculptured and rounded in profile (Fig. 13E, 14A) . . . . . Tetramorium smithi

36

return to couplet #34

Anterior edge or the dorsal pronotum with four evenly-spaced, stout hairs that are shorter than the spaces between them (Fig. 13C) . . . . . Tetramorium simillimum

Anterior dorsal pronotal hairs numbering more than four and longer than the spaces between them . . . . . 37

37

return to couplet #36

Hairs plumose, giving mesosoma fuzzy appearance (Fig. 13A, B) . . . . . Tetramorium lanuginosum

Mesosoma not fuzzy . . . . . 38

38

return to couplet #37

Mandibles with longitudinal striations . . . . . 39

Mandibles smooth or only weakly pitted . . . . . 40

39

return to couplet #38

Petiolar node quadrate; sculptured middle ridge of the frons distinct and cleanly split into two ridges that run parallel to each other at a point even with eyes, then rejoining before clypeus (Fig. 12C); dorsal propodeal spines longer than the height of the median peduncle by about half this height, about twice as long as ventral propodeal spines . . . . . Tetramorium bicarinatum

Petiolar node rounded in profile; middle ridge of frons indistinct, mixed with dense reticulate sculpturing, not temporarily split at level of eyes; dorsal propodeal spines equal to height of median peduncle and only slightly longer than ventral propodeal spines (Fig. 13F) . . . . . Tetramorium tonganum

40

return to couplet #38

First gastral tergite with basal costulae (rounded ridges) . . . . . Tetramorium pacificum

First gastral tergite without basal costulae . . . . . Tetramorium insolens

41

return to couplet #33

Combining the following: Clypeus with two longitudinal carinae; propodeum smoothly rounded lacking teeth or spines; last 3 segments of the antennae forming a distinct club . . . . . 42

Not with the above combination of characters . . . . . 47

42

return to couplet #41

Maximum diameter of the eyes more than half the width of the antennal club . . . . . 43

Maximum diameter of the eyes less than half the width of the antennal club . . . . . 46

43

return to couplet #42

Dorsal surface of head finely and evenly sculptured, dull . . . . . Monomorium pharaonis

Head shiny . . . . . 44

44

return to couplet #43

Terminal antennal segment about as long as preceding two combined; gaster dark brown to black, other parts of body yellow-brown . . . . . Trichomyrmex destructor

Terminal antennal segment distinctly longer than the combined length of previous two; coloration variable . . . . . 45

45

return to couplet #44

Petiole, including peduncle, longer than tall (Fig. 4F); dorsal pronotum distinctly lighter than the vertex of head . . . . . Monomorium floricola

Petiole, including peduncle, only about as long as tall (Fig. 4E); concolorous dark . . . . . Monomorium chinense-group

46

return to couplet #42

Mesepisternum smooth and shiny; propodeal angles broad, about 140 degrees (Fig. 5A) . . . . . Syllophopsis australica

Mesepisternum with coarse, reticulate sculpturing that gives it a dull appearance; propodeal angles steep, about 100 degrees (Fig 5B) . . . . . Syllophopsis sechellensis

47

return to couplet #41

Dorsal mesosoma without standing hairs . . . . . 48

Dorsal mesosoma with standing hairs . . . . . 52

48

return to couplet #47

Mesosoma in profile with distinct dorsal furrow separating propodeum from promesonotum; propodeal spines long and thin, about as long as the height of petiolar node peduncle (Fig. 3A); head and mesosoma yellow-orange, gaster dark brown . . . . . Cardiocondyla obscurior

Mesosoma smooth and continuous or with only a hint of a metanotal groove; propodeal spines not as long; head and gaster dark brown . . . . . 49

49

return to couplet #48

Postpetiolar sternite convex; maximum height of petiole about equal to maximum height of postpetiole . . . . . Cardiocondyla nuda

Postpetiolar sternite nearly flat; maximum height of petiole greater than maximum height of postpetiole . . . . . 50

50

return to couplet #49

Propodeal spines short and blunt; head, mesosoma, and gaster overall dark brown, the gaster only slightly darker . . . . . Cardiocondyla kagutsuchi

Propodeal spines distinct and pointed; mesosoma clearly lighter than gaster and head . . . . . 51

51

return to couplet #50

Metanotal groove absent but suggested by a slight impression in the mesosomal profile; mesosoma orange to warm yellow, and gaster black to dark brown . . . . . Cardiocondyla tjibodana

Metanotal groove completely absent, dorsal mesosoma flat or convex in profile; mesosoma yellow to brown, but without an orange or warm hue, and gaster black to dark brown . . . . . Cardiocondyla minutior

52

return to couplet #47

Combining the following: Petiole lacking anterior peduncle; frontal carinae elongate; antennal scrobes present; propodeum with thick, long (0.3 mm or longer) spines . . . . . 53

Petiole with anterior peduncle; frontal carinae indistinct and shorter than half the length of antennal scape; antennal scrobes weak or absent; propodeum with or without spines, but if with spines, less than 0.3 mm . . . . . 56

53

return to couplet #52

Propodeal spines approximately 0.5 mm long; pronotum flattened and marginate anteriorly and laterally . . . . . Romblonella palauensis

Propodeal spines 0.3 mm long; pronotum not marginate as described above . . . . . 54

54

return to couplet #53

Mesosomal dorsum with fine, reticulate sculpturing . . . . . 55

Mesosomal dorsum sculpturing predominately shallow longitudinal rugulae and coarse reticulations . . . . . Romblonella yapensis

55

return to couplet #54

Propodeal spines straight or very slightly curved at most; head dark brown, remainder of body light brown . . . . . Romblonella townesi

Propodeal spines distinctly curved; coloration of head, mesosoma, petiole, postpetiole, and gaster black . . . . . Romblonella sp. 6051940

56

return to couplet #52

Antennae nine-segmented and with a two-segmented club . . . . . Carebara atoma

Antennae 12-segmented, clubbing variable . . . . . 57

57

return to couplet #56

Antennae lacking apical club or appearing to have an indistinct four-segmented club; mesosoma generally smooth and shiny except for strongly punctate mesopleuron . . . . . Aphaenogaster osimenseis

Antennae with three-segmented apical club, indistinctly only in Rogeria sp. 25111995; mesosomal sculpturing variable . . . . . 58

58

return to couplet #57

Mesosomal profile smooth and more or less evenly convex, interrupted only by a small, notch-like metanotal groove . . . . . 59

Mesosomal profile concave in profile, dropping between pronotum and propodeum . . . . . 60

59

return to couplet #58

Dorsal propodeum between and anterior to propodeal spines coarsely punctate . . . . . Rogeria stigmatica

Dorsal propodeum between and anterior to propodeal spines smooth and shining . . . . . Rogeria sp. 25111995

60

return to couplet #58

Pronotal dorsum sculptured, not smooth and shining . . . . . 61

Pronotal dorsum smooth and shining . . . . . 63

61

return to couplet #60

Entire mesosoma of minors with deep, reticulate sculpturing (Fig 7A, B); (majors unknown) . . . . . Pheidole sp. 24041958

Entire mesosoma of minors with punctate sculpturing (Fig. 8B); majors with mostly punctate sculpturing, except for small smooth areas . . . . . 62

62

return to couplet #61

Majors: Frontal carinae short: punctate sculpturing near eyes blending with linear sculpturing between antennae; entire mesosoma mostly punctured, even under reticulate sculpturing, except for small patches under the pronotal protuberances; Majors and minors: entire body reddish brown to orange. Minors: dorsal propodeum fairly flat in profile . . . . . Pheidole nindi

Majors: Frontal carinae long, clearly separating punctate sculpturing near eyes from linear sculpturing between antennae; mesosoma mostly covered in punctate sculpturing, although reticulate sculpturing on pronotum and smooth patches on lateral pronotum and mesosoma distinct; Majors and minors: entire body blackish orange to ashy brown. Minors: dorsal propodeum convex in profile . . . . . Pheidole recondita

63

return to couplet #60

Pronotum and mesonotum fused to form the promesonotum; in minor workers, promesonotum shiny dorsally . . . . . 64

Pronotum and mesonotum separated by an impression that causes the mesonotum to look distinctly humped in side view, forming a separate section from pronotum and propodeum; mesonotum dull and sculptured dorsally . . . . . 65

64

return to couplet #63

Majors with a large, often blunt median hypostomal tooth, flanked closely by two teeth, one on each side (two lateral teeth, one each near the mandibular insertions, are also present but difficult to see); propodeal teeth of minors reduced to minute denticles . . . . . Pheidole umbonata

Major with two lateral hypostomal teeth (one each next to the mandibular insertions) only; minors with short but distinct propodeal teeth (Fig. 8A) . . . . . Pheidole megacephala

65

return to couplet #63

Majors: Area between eye and the antennal insertion with at least some reticulate sculpturing (Fig. 7C); dorsum of postpetiole mostly smooth and shining; majors and minors: propodeal spine horter than maximum width of propodeal spiracle (Fig. 7D) . . . . . Pheidole fervens

Majors: Area between eye and antennal insertion with longitudinal sculpturing only (Fig. 7E); dorsum of postpetiole mostly punctate, weakly shining; majors and minors: propodeal spine longer than maximum width of propodeal spiracle (Fig. 7F) . . . . . Pheidole oceanica

66

return to couplet #1

Entire body surface matte due to dense punctures . . . . . Prionopelta opaca

Body surface slightly shining due to weaker sculpturing . . . . . Prionopelta kraepelini

67

return to couplet #3

Mandibles long, falcate, and without teeth; pretarsal claws pectinate . . . . . Leptogenys falcigera

Mandibles and pretarsal claws not as above . . . . . 68

68

return to couplet #67

Mandibles long, slender, straight, bent sharply at apex (Fig. 1A) . . . . . 69

Mandibles short and more or less triangular . . . . . 71

69

return to couplet #68

Petiolar node with a single, sharp, apical spine . . . . . Odontomachus simillimus

Apex of petiolar node rounded or acute, but no spine present . . . . . 70

70

return to couplet #69

Dorsal surface of head and pronotum largely smooth and shining; petiolar apex acute in profile; head notably darker than remainder of body . . . . . Anochetus splendidulus

Median dorsal surface of head and usually rest of pronotal dorsum with conspicuous sculpture; petiolar apex rounded in profile; body and head concolorous, usually dark brown, although many specimens orange . . . . . Anochetus graeffei

71

return to couplet #68

Pretarsal claws with a single median tooth (Fig. 8C); petiolar node longer than wide when viewed from above; body nearly devoid of erect hairs; antennal insertions widely separated by broad clypeus; hind legs with 2 pectinate spurs at apex of tibia . . . . . Platythyrea parallela

Pretarsal claws simple; petiolar node usually broader or nearly as broad as long when viewed from above; body with erect hairs; antennal insertions closely approximated; tibial spurs not as above . . . . . 72

72

return to couplet #71

Apex of hind tibia with two spurs: a large pectinate spur behind a much smaller, simple spur . . . . . 73

Apex of hind tibia with one large pectinate spur . . . . . 75

73

return to couplet #72

Sides of pronotum with fine longitudinal striations . . . . . Brachyponera atrata

Sides of pronotum without striations . . . . . 74

74

return to couplet #73

In profile, mesosoma flat or weakly convex, propodeum continuous with promesonotum; mesopleuron rough and dull with various degrees of pilosity . . . . . Pseudoponera stigma

Mesosoma when viewed in profile with a distinct drop from mesonotum down to propodeum; mesopleuron smooth and shining, without hairs or sculpturing . . . . . Brachyponera luteipes

75

return to couplet #72

Compound eyes absent (Figs. 1B, 3F) . . . . . 76

Compound eyes present . . . . . 77

76

return to couplet #75

In profile, anterior face of petiole strongly concave while posterior face lightly convex (Figs. 1B, 4A); head and gaster with blackish-orange coloration . . . . . Cryptopone butteli

In profile, petiole with anterior and posterior faces sloping upward at nearly equal angles (Fig. 4B); body concolorous orange or head and gaster slightly darker . . . . . Cryptopone testacea

77

return to couplet #75

Ventral keel of petiole with a small translucent “window” and with two small teeth projecting posteriorly (Fig. 9A) . . . . . 78

Ventral keel of petiole simple, lobe-like, completely opaque . . . . . 82

78

return to couplet #77

Mesometanotal suture distinctly visible on dorsal mesonotum; antennae with a weak, five-segmented club; HW 0.36–0.40 mm . . . . . Ponera incerta

Mesometanotal suture absent from dorsal mesonotum; antennal club variable; HW usually larger or smaller . . . . . 79

79

return to couplet #78

Large species (HW 0.51–0.58); mesosoma dorsum with numerous erect hairs; antennal club indistinctly four- or five-segmented . . . . . Ponera loi

HW smaller; dorsal mesosoma lacking standing hairs; antennal club distinctly four-segmented . . . . . 80

80

return to couplet #79

Tiny species (HW 0.325 mm in single specimen); antennae with four-segmented club; anterior gaster with distinct corners when viewed from above (Fig 8E); overall color light orange-brown . . . . . Ponera sp. 10091995

HW 0.39–0.48 mm; gaster and antennal club not as above (Fig 8F); color orangish brown to dark brown . . . . . 81

81

return to couplet #80

Petiolar node wide (PNI 80–93); HW 0.43–0.48 . . . . . Ponera clavicornis

Petiolar node narrow (PNI 66–78), HW 0.39–0.45 . . . . . Ponera tenuis

82

return to couplet #77

Petiolar node tapering dorsally, and its height (not counting the ventral process) distinctly greater than length; mesepisternum usually smooth and outlined by a carina . . . . . 83

Anterior and posterior faces of petiolar node parallel, or if tapering slightly, then the height (not counting ventral process) nearly the same as the length; mesepisternum usually sculptured and fused with mesonotum . . . . . 84

83

return to couplet #82

Eyes with 6 or fewer ommatidia (average of 4) (Fig. 4C); petiolar node tapering, but not severely, its dorsal tip flattened; often orange-brown, although some specimens dark brown . . . . . Hypoponera confinis

Eyes with 7 to 20 ommatidia (average of 12); petiolar node tapering significantly, often creating a narrow, rounded dorsal point in profile; color dark brown to black . . . . . Hypoponera pruinosa

84

return to couplet #82

Petiole quadrate, its length at base about the same as petiole height, not counting ventral process (Fig. 4D) . . . . . Hypoponera punctatissima

Petiolar node tall and parallel-sided in profile . . . . . Hypoponera opaciceps

85

return to couplet #3

Petiole and propodeum with a pair of spines . . . . . 86

Petiole and propodeum without spines . . . . . 87

86

return to couplet #85

Dorsal mesosoma bordered by a flange that starts behind the head and continues to the propodeal spines; flange forming distinct corners on anterior-lateral pronotum (Fig 8D) . . . . . Polyrhachis sp. 91952

Dorsal mesosoma missing a flange; anterior-lateral pronotum with sharp spines . . . . . Polyrhachis dives

87

return to couplet #85

Antennae with 9 segments . . . . . Brachymyrmex obscurior

Antennae with 11 or 12 segments . . . . . 88

88

return to couplet #87

Antennal sockets set back from rear border of clypeus; antennae 12- segmented; workers polymorphic . . . . . 89

Antennal sockets located at rear border of clypeus; antennae 11- or 12-segmented; workers monomorphic . . . . . 98

89

return to couplet #88

Petiolar node flattened (Fig. 2D) . . . . . 90

Petiolar node a raised projection or point (Fig. 2A–C, E–F) . . . . . 91

90

return to couplet #89

Clypeus wider than tall; head tapering toward mandibles in front view; head and mesosoma reddish orange . . . . . Camponotus erythrocephalus

Clypeus width and height nearly the same or slightly taller than wide; head nearly square in front view; body overall matte black . . . . . Camponotus peleliuensis

91

return to couplet #89

Propodeum with distinct dorsal and posterior faces, mesosoma almost squarish in profile (Fig. 2E) . . . . . 92

Propodeum lacking distinct dorsal and posterior faces, sloping with varying degrees of smoothness . . . . . 93

92

return to couplet #90

Dorsum of gaster with a shiny coat of gold hairs; mesosoma and petiole with silver hairs of various lengths covering both dorsum and sides; body color uniformly black . . . . . Camponotus flavicomans

Dorsum of gaster lacking coat of gold hairs: body overall mahogany to black and hairs silver and scattered . . . . . Camponotus marianensis

93

return to couplet #91

Gastral tergites with orange-brown posterior margins and yellow coloration anteriorly, creating a gaster with distinct transverse stripes . . . . . Camponotus variegatus

Gaster not as above . . . . . 94

94

return to couplet #93

Heads of smaller workers about as wide as long (excluding mandibles); propodeum in profile not sloping smoothly (Fig. 2F); mesosoma and gaster equally black or deep brown, although can fade to lighter shades at joints . . . . . 95

Heads of all workers, but especially small ones, much longer than wide (excluding mandibles); propodeum in lateral view sloping smoothly to petiolar insertion (Fig. 2A, B, C); mesosoma yellow-orange to reddish brown (at least posteriorly), head and gaster orange or dark brown to black . . . . . 96

95

return to couplet #94

Mesosoma with long, recumbent, silver hairs which are especially abundant on the dorsal surface . . . . . Camponotus sp. 121958

Mesosoma with some long standing hairs and more numerous small, fine, recurved hairs . . . . . Camponotus reticulatus

96

return to couplet #94

Maximum HW 2.3 mm and maximum HL 2.6 mm in major workers; maximum total body length 6.5 mm . . . . . 97

Maximum HW 2.8 mm and maximum HL 3.0 mm in major workers; maximum total body length exceeding 8.0 mm . . . . . Camponotus sp. 1945

97

return to couplet #96

Long, standing hairs lateral to eyes present in majors; head and gaster orange, mesosoma often more yellow . . . . . Camponotus chloroticus

Long, standing hairs absent in majors; head and gaster dark brown to black, mesosoma yellow to yellow-orange . . . . . Camponotus eperiamorum

98

return to couplet #88

HW < 0.4 mm and mesosoma without standing hairs . . . . . Tapinoma (all species)

HW > 0.5 mm, but if smaller (as in Paratrechina minutula, below), then mesosoma with standing hairs . . . . . 99

99

return to couplet #98

Antennal scapes more than 1.5X length of head . . . . . 100

Antennal scapes less than 1.5X length of head . . . . . 101

100

return to couplet #99

Dorsum without standing hairs . . . . . Anoplolepis gracilipes

Dorsum with numerous standing hairs . . . . . Paratrechina longicornis

101

return to couplet #99

Anterior clypeal border evenly rounded, straight, or slightly concave; dorsal mesosoma with pubescence and coarse, standing hairs . . . . . 102

Anterior mid-clypeal border with distinct concavity that in some cases appears as an obvious notch (Technomyrmex), or clypeal border with a projection (Iridomyrmex) in the middle; dorsal mesosoma without coarse, standing hairs, although some fine standing hairs are visible . . . . . 105

102

return to couplet #101

HW < 0.4 mm; black, coarse, standing hairs on mesosoma; overall yellow (except for population on Guam, which is dusky orange-brown) . . . . . Paraparatrechina minutula

HW > 0.4 mm; brown, black, or gray . . . . . 103

103

return to couplet #102

Upper sides of propodeum glossy (above the spiracle); katepisternum dark brown, bulbous and glossy, without pubescence or sculpturing (Fig. 6A–C) . . . . . Nylanderia clandestina

Sides of propodeum above the spiracle pubescent; katepisternum not as above . . . . . 104

104

return to couplet #103

Katepisternum pubescent; significant pubescence between propodeal spiracle and dorsum which continues ventrally anterior to propodeal spiracle (Fig. 5E) . . . . . Nylanderia bourbonica

Katepisternum glossy and without hairs (a few isolated hairs may be present along posterior and ventral borders of both katepisternum and pronotum, and a few isolated hairs may appear at central portion of katepisternum); pubescence between propodeal spiracle and dorsum slight and lacking pubescence around spiracle and often anteriorly to border with katepisternum (Fig 5F) . . . . . Nylanderia vaga

105

return to couplet #101

Anterior clypeal border with projection in middle; petiole with distinct node that rises steeply to height more than half that of propodeum; dorsal mesosoma without standing hairs . . . . . Iridomyrmex anceps

Anterior clypeal border with notch in middle; petiole a flattened scale, often covered by gaster; dorsal mesosoma with standing hairs . . . . . 106

106

return to couplet #105

Body length approximately 2 mm; antennal scapes barely extending beyond vertex; uniformly dark grey . . . . . Technomyrmex albipes

Body length > 2 mm; antennal scapes clearly reaching beyond vertex by more than one fourth their length; uniformly brown . . . . . Technomyrmex kraepelini