Key to Micronesian Ants

This worker key is based on: [[Media:Clouse 2007a.pdf|Clouse, R. M. 2007. The Ants (Hymenoptera: Formicidae) of Micronesia. Micronesica. 39(2): 171–296. PDF]]

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List of Micronesia Ant species

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 . . . . . Cerapachys 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 spongy substance (Fig. 11D) . . . . . 12
 * Posterior propodeum to anterior gaster covered with a light-colored,


 * 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