Key to the Afrotropical Aenictus

This worker key is based in Gómez (2022)

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1

 * Head glassy smooth [Figure 2A]; femora with their distal halves expanded [Figure 2C] (Maximum width / minimum width ~ 3-4) . . . . . 2
 * Head alutaceus to heavily reticulated, matt [Figure 2B]; femora subcylindrical [Figure 2D] (Maximum width / minimum width < 2) . . . . . 7 (koloi group)

2
return to couplet #1
 * Mandibles either linear or triangular, never with either a large blunt, rounded basal tooth nor with its basal half expanded and semi-spherical [Figure 1A, C, D, G, H] . . . . . 3


 * Mandibles massive, neither linear nor triangular, either with a large, blunt, rounded basal tooth separated from the rest by a depression (mitten-shaped) or with its basal half expanded and semi-spherical [Figure 1E, F] . . . . . 6

3
return to couplet #2
 * Mandibles linear, leaving a gap between themselves and the clypeus when closed. Clypeus reduced to two triangular minute teeth between or beneath the antennal sockets [Figure 1C, D] . . . . . 11 (eugenii group)


 * Mandibles linear to triangular with no gap between themselves and the clypeus when mandibles closed. Clypeus usually with a row of minute triangular denticles, and never reduced to two triangular minute teeth between or beneath the antennal sockets [Figure 1A, G, H] . . . . . 4

4
return to couplet #3
 * Mandibles very long, crossing over at the mid-length when closed, each mandibular apex clearly reaching the opposite antennal insertion; apical tooth massive, usually without preapical tooth or denticles [Figure 1G] . . . . . asantei group, one species: Aenictus asantei


 * Mandibles linear to triangular, neither crossing over at the mid-length nor with each mandibular apex; preapical tooth and/or denticles may be present [Figure 1A, H] . . . . . 5

5
return to couplet #4
 * Mandibles linear, with three or four defined teeth. Clypeus reduced to a thin line, virtually not visible in frontal view [Figure 1H] . . . . . 12 (rixator group)


 * Mandibles triangular, always with more than 4 teeth or denticles in total. Dentition variable, usually with one apical tooth followed by a preapical tooth and/or a series of smaller denticles, but some species with an apical tooth followed by smaller well defined triangular teeth. Clypeus present as a narrow lamella or a row of triangular denticles, sometimes small and difficult to see when mandibles closed [Figure 1A] . . . . . 13 (rotundatus group)

6
return to couplet #2
 * Mandibles with basal half expanded and semi-spherical, surrounded by a thin cutting edge [Figure 1E] . . . . . popeyei group, one species: Aenictus popeyei


 * Mandibles with a conspicuous, blunt, large proximal tooth clearly separated from the rest of the mandible, mitten shaped [Figure 1F] . . . . . 9 (decolor group)

7
return to couplet #5
 * Numerous long, white, semierect to erect setae present on scapes, dorsum of mesosoma, petiole, postpetiole and femora. Petiole with clearly more than 10 setae [Figure 22C] . . . . . Aenictus susanae


 * Scattered white, erect setae present on scapes, dorsum of mesosoma, petiole, postpetiole and femora. Petiole with 4 to 8 setae . . . . . 8

8
return to couplet #7
 * Subpetiolar process small, size similar to the prora, shaped as a quarter of ellipse with the vertical face facing forward, followed by an almost horizontal ovoid lamella [Figure 20C]; smaller size (HW< 0.60) . . . . . Aenictus koloi


 * Subpetiolar process very developed, subrectangular and followed by a rectangular lamella usually inclined 45 degrees forward, the whole process clearly larger than the prora [Figure 24C]; larger size (HW>0.65) . . . . . Aenictus xegi

9
return to couplet #8
 * Scapes relatively shorter, slightly surpassing three quarters of head length when laid back (SIL<80), smaller size (HL<0.70, WL<1.15) . . . . . Aenictus bidentatus


 * Scapes relatively longer, distinctly surpassing three quarters of head length when laid back (SIL>80), larger size (HL>0.70, WL>1.15) . . . . . 10

10
return to couplet #9
 * Scapes reaching three quarters of the head length when laid back (8095). Subpetiolar process small and shaped as a quarter of ellipse, with its vertical line anteriorly located [Figure 9C]. . . . . Aenictus villiersi

11
return to couplet #3
 * Scapes with dense, reclined setae that are shorter than scape width, without erect to semierect setae that are much longer than maximum scape width [Figure 18A]; mesosoma covered with subequal reclined short setae, shorter than petiole height [Figure 18C]. Size clearly smaller (0.47<HW<0.63) . . . . . Aenictus mvuvii


 * Scapes with erect to semierect setae that are much longer than maximum scape width [Figure 11A]; mesosoma covered with erect to semierect long setae, unequal in size, the longest clearly longer than petiole height [Figure 11C]. Size larger (0.63<HW<0.94) . . . . . Aenictus eugenii

12
return to couplet #5
 * Ridge separating dorso and posteropropodeum present and clearly visible projecting from the dorsal propodeal surface [Figure 30C]. Mandibles with three teeth similar in size . . . . . Aenictus rixator


 * Ridge separating dorso and posteropropodeum absent, so dorso and posteroprodeum form a smooth continuous surface [Figure 28C]. Mandibles with an apical tooth followed by three smaller denticles . . . . . Aenictus mentu

13
return to couplet #5
 * Scapes relatively very short (SIL<58). If 58 62). If 5862)
 * SIL <58, usually SIL <56 . . . . . 15

15
return to couplet #14
 * Lateral surfaces of mesonotum, propodeum, petiole and postpetiole covered with a white, short, dense pubescence, much shorter than setae on dorsal surfaces (best viewed in dorsal view) [Figure 39D] . . . . . Aenictus steindachneri


 * Lateral surfaces of mesonotum, propodeum, petiole and postpetiole bare, setation restricted to some occasional isolated setae [Figure 54D] . . . . . 16

16
return to couplet #15
 * Dorsopropodeum densely sculptured, punctated-reticulated even in the minima workers as a faint reticulum [Figure 35D, Figure 34D]. Dorsopronotum with very dense pilosity, covered with more than 20 white short reclinated setae, without bare zones where cuticle is clearly seen [Figure 35C, Figure 35C] . . . . . Aenictus hitai


 * Dorsopropodeum smooth, although some kind of shagreened sculpturation may be present laterally [Figure 32D, Figure 37D]. Dorsopronotum with very sparse pilosity, clearly with less than 20 white short setae, extensive zones bare where cuticle is clearly seen [Figure 32C, Figure 37C] . . . . . 17

17
return to couplet #16
 * Metanotal groove demarcated, slightly indented in profile and dorsal views; postpetiole with clearly defined anterior and posterior vertical faces, subrectangular with rounded angles and relatively higher (PPI: 113 [107-127]) [Figure 32C, D]. Western Africa . . . . . Aenictus boltoni


 * Metanotal groove not demarcated, mesopropodeal profile almost a straight line; postpetiole hemispherical, without anterior and posterior vertical faces and relatively lower (PPI: 138 [130-150]). Southern Africa [Figure 37C, D] . . . . . Aenictus mariae

18
return to couplet #13
 * Setae adpressed everywhere [Figure 41A, C]. Clypeus with a row of very conspicuous long, conical teeth, much longer than wide, the two central smaller than the rest [Figure 41]. Subpetiolar process subrectangular, clearly lower than long, oriented 45° forward, mostly digit shaped [Figure 41C] . . . . . Aenictus congolensis


 * Setae from semierect to erect everywhere [Figure 44A, C]. Clypeus with a row of triangular teeth, about as long as wide [Figure 44E]. Subpetiolar process never digitiform and elongated, but ellipsoidal, followed or not by a lamella . . . . . 19

19
return to couplet #18
 * Scapes very long (SIL >80). Meatanotal groove in profile wide, rounded, U-shaped [Figure 54C] . . . . . Aenictus nyuyi


 * Scapes short (SIL<75). Metanotal groove in profile not conspicuous, V-shaped as the mesonotum meets the propodeum at an angle [Figure 59A] . . . . . 20

20
return to couplet #19
 * Setae on dorsal surface of mesosoma reclined, very abundant and with similar length [Figure 32C, Figure 37C]; lateral surfaces of head covered with clearly more than 20 small, adpressed setae, the size of each about equal to the maximum scape width [Figure 32A, Figure 37A] . . . . . Aenictus jacki


 * Setae on dorsal surface of mesosoma erect to semierect and scattered, unequal, with some setae clearly longer than petiole height [Figure 59C]; lateral surfaces of head almost bare, with clearly less than 20 long setae, the size of each clearly longer than the maximum scape width [Figure 59A] . . . . . 21

21
return to couplet #20
 * Head subquadrate (CI>95) [Figure 59A] with stouter mesosoma (WL/PRW<250) [Figure 59C, D] . . . . . Aenictus ugaduwensis


 * Head more elongated (CI<93) [Figure 61A] with more slender mesosoma (WL/PRW>270) [Figure 61C, D] . . . . . 22

22
return to couplet #21
 * Dorso and posteropropodeum separated by a developed, horizontal ridge clearly visible in lateral view, so there is not a smooth transition into each other [Figure 61C]; in dorsal view this ridge projecting itself as a horizontal shelf, not reduced to a single line [Figure 61D]. Subpetiolar process elongated and without lamellae, usually a quarter ellipse with its vertical side anteriorly, overall size clearly smaller than petiolar node [Figure 61C] . . . . . Aenictus weissi


 * Dorso and posteropropodeum not separated by a horizontal ridge, so having a continuous smooth transition into each other [Figure 44C]; if a continuous ridge is present laterally and dorsally, it’s weak and in dorsal view only a faint line, not projecting itself as a horizontal shelf [Figure 44D]. Subpetiolar process rounded and usually with a triangular to ellipsoidal lamella . . . . . 23

23
return to couplet #22
 * PL/PH>1.35. If 1.250. East and Southern Africa . . . . . Aenictus rotundatus