Key to Pheidole minors of Borneo

This worker key is based on: [[Media:Eguchi 2001a.pdf| Eguchi, K. 2001a. A revision of the Bornean species of the ant genus Pheidole (Insecta: Hymenoptera: Formicidae: Myrmicinae). Tropics Monograph Series. 2:1-154. PDF]]

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1

 * Antenna with 3-segmented club . . . . . 5


 * Antenna with 5-segmented club, or without conspicuous club . . . . . 2

2
return to couplet #1
 * Apical five antennal segments distinctly elongate, and forming conspicuous club; posterior part of head never forming elongate neck . . . . . 3


 * Antenna lacking conspicuous club; posterior part of head forming extremely elongate neck . . . . . 4

3
return to couplet #2
 * Promesonotal dome relatively high; metanotal groove in profile indistinct; in profile posterior declivity of promesonotal dome and dorsum of propodeum bearing ca. 10 standing hairs in total . . . . . Pheidole quinata


 * Promesonotal dome relatively low; metanotal groove in profile distinct; in profile posterior declivity of promesonotal dome and dorsum of propodeum bearing more than 20 standing hairs in total . . . . . Pheidole sabahna

4
return to couplet #2
 * Propodeal spine more than 4 times as long as diameter of propodeal spiracle; body light brown to brown . . . . . Pheidole montana


 * Propodeal spine 2-2.5 times as long as diameter of propodeal spiracle; body brown to dark brown . . . . . Pheidole comata or Pheidole longipes

5
return to couplet #1
 * Promesonotum armed with a pair of long and pointed spines . . . . . 6


 * Promesonotum unarmed, or armed with a pair of processes, but the processes never developed into long and pointed spines (the processes of Pheidole aristotelis well developed but truncate or blunt apically) . . . . . 10

6
return to couplet #5
 * Propodeal spine elongate-triangular, ca. 1.5 times as long as diameter of propodeal spiracle; head smooth and shining . . . . . Pheidole quadricuspis


 * Propodeal spine horn-like, more than 4 times as long as diameter of propodeal spiracle; head usually sculptured at least partly (in Pheidole acantha head sometimes almost smooth and shining) . . . . . 7

7
return to couplet #6
 * Petiolar node in profile acute at apex; dorsum of alitrunk in profile bearing less than 10 standing hairs . . . . . Pheidole acantha


 * Petiolar node in profile blunt at apex; dorsum of alitrunk in profile usually bearing more than 20 standing hairs . . . . . 8

8
return to couplet #7
 * Head punctured, or largely smooth and shining and partly punctured . . . . . Pheidole spinicornis
 * Head strongly reticulate . . . . . 9

9
return to couplet #8
 * Body smaller (AL 1.00-1.20 mm); propodeal spine usually directed upward . . . . . Pheidole quadrensis
 * Body larger (AL 1.74-1.83 mm); propodeal spine usually directed posterodorsally . . . . . Pheidole lokitae

10
return to couplet #5
 * Legs from apex of femur to apex of tersus ivory-white contrasted with the remainder of femur which is dark brown . . . . . Pheidole fantasia


 * Legs almost unicolored . . . . . 11

11
return to couplet #10
 * Eye consisting of 5-6 ommatidia . . . . . Pheidole parvicorpus


 * Eye consisting of more than 10 ommatidia . . . . . 12

12
return to couplet #11 dorsally on head; posterior declivity of promesonotal dome always without a distinct prominence . . . . . 13
 * Head at least above subocular level distinctly sculptured; occipital carina weak or absent


 * Head not, or only weakly, sculptured; occipital carina variable in condition; posterior declivity of promesonotal dome with, or without, a prominence . . . . . 23

13
return to couplet #12
 * Dorsum of head punctured; ventrolateral face of head below subocular level smooth and shining in at least its anterior half . . . . . 14


 * Dorsum of head punctured or reticulate; ventrolateral face of head below subocular level entirely punctured or reticulate; when venter of head less-sculptured (in P. retivertex sp. nov. and P. gombakensis sp. nov.), dorsum of head not punctured but largely rugoso-reticulate . . . . . 16

14
return to couplet #13
 * In profile head below subocular level punctured and dull in its posterior half; petiolar node higher; eye broader . . . . . Pheidole bugi


 * In profile head below subocular level entirely smooth and shining; petiolar node lower; eye narrower . . . . . 15

15
return to couplet #14
 * Body brown . . . . . Pheidole rugifera


 * Body dark brown to blackish brown . . . . . Pheidole tenebricosa

16
return to couplet #13
 * Both head and alitrunk reticulate; propodeal spine ca. 6 times as long as diameter of propodeal spiracle . . . . . Pheidole sayapensis


 * At least mesopleuron and lateral face of propodeum punctured; propodeal spine usually less than 4.5 times as long as diameter of propodeal spiracle . . . . . 17

17
return to couplet #16
 * Promesonotum with a pair of well-developed spines with blunt apices . . . . . Pheidole aristotelis


 * Promesonotum unarmed, or only with a pair of low tubercles which never develop into distinct spines . . . . . 18

18
return to couplet #17
 * Median part of clypeus distinctly punctured and dull . . . . . 19


 * Median part of clypeus smooth and shining . . . . . 20

19
return to couplet #18
 * Posterior declivity of promesonotal dome relatively steep; propodeal spine longer than that of P. rabo . . . . . Pheidole tjibodana


 * Posterior declivity of promesonotal dome relatively gentle; propodeal spine shorter than that of P. tjibodana . . . . . Pheidole rabo

20
return to couplet #18
 * Promesonotum without a pair of tubercles; propodeal spine triangular or elongate-triangular, at most twice as long as diameter of propodeal spiracle . . . . . 21


 * Promesonotum with a pair of low tubercles; propodeal spine horn-like, at least 3 times as long as diameter of propodeal spiracle . . . . . 22

21
return to couplet #20
 * Promesonotum smooth and shining . . . . . Pheidole gombakensis


 * Lateral part of promesonotum weakly punctured . . . . . Pheidole retivertex

22
return to couplet #20
 * Ventrolateral face of head below subocular level punctured . . . . . Pheidole angulicollis


 * Ventrolateral face of head below subocular level reticulate . . . . . Pheidole poringensis

23
return to couplet #12
 * Propodeal spine extremely long, extending over petiole . . . . . Pheidole modiglianii


 * Propodeal spine sometimes long, but never extending over petiolar node . . . . . 24

24
return to couplet #23
 * Alitrunk completely lacking standing hairs . . . . . Pheidole huberi


 * Alitrunk bearing standing hairs . . . . . 25

25
return to couplet #24
 * Declivitous face of promesonotal dome without any distinct prominence . . . . . 26


 * Declivitous face of promesonotal dome with a prominence . . . . . 39

26
return to couplet #25
 * Petiolar node very high; mesopleuron divided into two parts, of which lower part is more or less margined dorsally . . . . . 27


 * Petiolar node not so high; mesopleuron usually not divided into upper and lower parts; if it is divided into two parts, the lower part is usually not margined dorsally . . . . . 28

27
return to couplet #26
 * Longest axis of eye having 4 ommatidia; body yellowish brown . . . . . Pheidole sarawakana


 * Longest axis of eye having at least 5 ommatidia; body yellowish brown to dark brown . . . . . Pheidole sauberi or . . . . . Pheidole elisae

28
return to couplet #26
 * Occipital carina complete . . . . . 29


 * Occipital carina almost evanescent, or absent dorsally on head . . . . . 36

29
return to couplet #28
 * Distance between mandibular insertion and anterior margin of eye 1.5-1.6 times as long as maximal diameter of eye . . . . . Pheidole havilandi


 * Distance between mandibular insertion and anterior margin of eye at most 1.1 times as long as maximal diameter of eye . . . . . 30

30
return to couplet #28
 * Metanotal groove in profile being a deep emargination . . . . . Pheidole tawauensis


 * Metanotal groove shallow or indistinct . . . . . 31

31
return to couplet #30
 * Petiole more than 1.7 times as long as postpetiole; anterior declivity of promesonotal dome in profile relatively steep . . . . . Pheidole lucioccipitalis


 * Petiole at most 1.5 times as long as postpetiole; anterior declivity of promesonotal dome in profile relatively gentle . . . . . 32

32
return to couplet #31
 * Several conspicuous rugulae running immediately above eye . . . . . Pheidole submonticola


 * No conspicuous rugulae running immediately above eye . . . . . 33

33
return to couplet #32
 * Upper part of mesopleuron, and lateral face of propodeum largely smooth and shining . . . . . 34


 * Mesopleuron and lateral face of propodeum punctured . . . . . 35

34
return to couplet #33
 * Eye small, with ca. 5 ommatidia on longest axis; head in full-face view oval . . . . . Pheidole upeneci


 * Eye large, with ca. 10 ommatidia on longest axis; head in full-face view subrectangular . . . . . Pheidole manukana

35
return to couplet #33
 * Body yellowish brown; promesonotum with a pair of very low tubercles dorsolaterally . . . . . Pheidole kikutai


 * Body brown; promesonotum without tubercles . . . . . Pheidole megacephala

36
return to couplet #28
 * Propodeal spine 3.5-4 times as long as diameter of propodeal spiracle . . . . . Pheidole deltea


 * Propodeal spine at most twice as long as diameter of propodeal spiracle . . . . . 37

37
return to couplet #36
 * In profile promesonotum convex, with steep posterior declivity . . . . . Pheidole hortensis or Pheidole clypeocornis


 * In profile promesonotum evenly convex, or flat and low . . . . . 38

38
return to couplet #37
 * Promesonotal dome in profile lower, and flatter dorsally; CI 89-95 . . . . . Pheidole merimbun or Pheidole planidorsum


 * Promesonotal dome in profile higher, and convexer dorsally; CI 84-89 . . . . . Pheidole butteli

39
return to couplet #25
 * Promesonotum with a pair of low tubercles . . . . . 40


 * Promesonotum without a pair of tubercles . . . . . 41

40
return to couplet #39
 * Distance between mandibular insertion and anterior margin of eye 1.3-1.5 times as long as maximal diameter of eye; postpetiole 2.3-2.5 times as broad as petiolar node; anterior declivity of promesonotal dome relatively steep; lateral face of promesonotum weakly punctured . . . . . Pheidole ghigii


 * Distance between mandibular insertion and anterior margin of eye 0.9-1.0 times as long as maximal diameter of eye; postpetiole 2.0-2.2 times as broad as petiolar node; anterior declivity of promesonotal dome relatively gentle; lateral face of promesonotum smooth and shining . . . . . Pheidole plinii

41
return to couplet #39
 * Prominence on posterior declivity of promesonotal dome, and dorsum of propodeum each bearing a pair of standing hairs . . . . . Pheidole cariniceps


 * Prominence on posterior declivity of promesonotal dome, and dorsum of propodeum each bearing more than one pair of standing hairs . . . . . 42

42
return to couplet #41
 * Occipital carina forming a well-developed flange, which is in full-face view narrowed at its base . . . . . Pheidole aglae


 * Occipital carina sometimes forming a flange, but in full-face view not narrowed at base . . . . . 43

43
return to couplet #42
 * Clypeus weakly and irregularly rugose and weakly shining . . . . . Pheidole plagiaria


 * Clypeus smooth and shining . . . . . 44

44
return to couplet #43
 * Large part of dorsum of head very weakly punctured; promesonotal dome in profile higher and rounder . . . . . Pheidole inornata


 * Dorsum of head except the area around antennal insertion smooth over the surface; promesonotal dome in profile lower . . . . . 45

45
return to couplet #44
 * Lower part of mesopleuron smooth and shining, or slightly punctured; petiole 0.9-1.0 times as long as postpetiole . . . . . Pheidole annexa


 * Mesopleuron punctured; petiole at least 1.3 times as long as postpetiole . . . . . 46

46
return to couplet #45
 * Head broader (CI 82-87) . . . . . Pheidole fervens


 * Head narrower (CI 78-81) . . . . . Pheidole orophila