Aenictus Shuckard, 1840

Gómez, Kiko, 2022, A revision of the Afrotropical species of the Dorylinae ant genus Aenictus (Hymenoptera: Formicidae) based on the worker caste, Belgian Journal of Entomology 124, pp. 1-86 : 6-16

Genus Aenictus Shuckard, 1840

Aenictus SHUCKARD, 1840: 266 .

Type-species: Aenictus ambiguus , by original designation.

Enictus WALKER, 1860: 306 ; SMITH, 1865: 79; incorrect subsequent spellings of Aenictus: BOLTON, 1995: 19 . [unavailable name].

Paraenictus WHEELER, 1929: 27 [as subgenus of Aenictus ]. Type-species: Aenictus (Paraenictus) silvestrii , by monotypy. [Junior synonym of Aenictus: WILSON, 1964: 444 ].

Typhlatta SMITH, 1857: 79 . Type-species: Typhlatta laeviceps , by monotypy. [Junior synonym of Aenictus: FOREL, 1890 : ciii.; revived from synonymy as subgenus of Aenictus: WHEELER, 1930: 198 ; junior synonym of Aenictus: WILSON, 1964: 444 ].

An excellent account on morphology, phylogeny, taxonomy and biology of the genus is given in BOROWIEC (2016), including a detailed description for worker and male castes. FISHER & BOLTON (2016) also diagnoses the worker caste for the Afrotropical species. The following notes complement these two main sources and apply solely to the worker caste of the Afrotropical species.

Most species are monomorphic, with some having a wide range of sizes (e.g. CSR up to 144 for A. eugenii ) but without marked allometric morphological differences among the maxima and minima workers other than size, colour or sculpturation. However, some species in the rotundatus group represent the extreme of this variation with noticeable allometry in some indexes (e.g. A. hitai sp. nov. 0.28<HW<0.60, CSR 178, 74<CI<100) which led EMERY (1895) to comment about A. mariae “it is hardly correct to say that workers of this species are monomorphic”. As a rule of thumb, minima workers present smaller SIL and CI than maxima workers, meaning that they have more elongated heads with relatively shorter scapes.

Some Asian Aenictus species possess clearer cuticular patches laterally at the upper half of the head (“ Typhlatta spot”), but this character is always absent in the Afrotropical species described to date. In the Afrotropical species antennae are 10 segmented, with subcylindrical scapes, bent outwards in frontal view and widening in its apical half to almost twice its width, usually the basal third narrow and the rest widening to the apex. Its length range from short to medium (30<SIL<100) not reaching the occipital margin and never as long as in some Asian species groups where scapes reach and even surpass the occipital margin (A. hottai, A. inflatus, A. laeviceps, A. pachycerus, A. wroughtonii (part) groups) ( JAITRONG & YAMANE, 2011).

Mandible shape is remarkably diverse among the Afrotropical species and relatively stable within species groups. As a consequence, mandible shape is the main character used to define such groups. Most species display linear or triangular shapes, but may have highly specialized morphology (as in the decolor or popeyei groups which are not present in any other Aenictus group worldwide). Mandibular dentition is also variable and linked to the mandibular shape. In triangular mandibles it consists of a long apical tooth followed or not by a preapical, and up to 8–12 smaller denticles, but in the rixator group with 3–4 defined teeth, in the asantei group just an apical tooth and in the decolor and popeyei groups apical and preapical tooth. No Afrotropical species has a row of basal teeth or denticles as seen in the Asian minutulus (formerly piercei) group ( JAITRONG & HASHIMOTO, 2012) nor a large basal tooth as in the Asian javanus group ( JAITRONG & YAMANE, 2012). Sometimes a sharp, differentiated edge can be present basally (e.g. A. popeyei ), but in most species the basal mandibular margin is flat and undifferentiated.

Usually pro- and mesonotum are convex and the propodeum almost flat, both meeting at an angle, except for some minute species with almost flat mesosoma in lateral view (e.g. rixator species group or minima workers in rotundatus species group). Mesonotum-mesopleuron ridge is always absent (present in the Asian philippinensis group) ( JAITRONG & YAMANE, 2012).

Petiole is always sessile or weakly subsessile. Subpetiolar process is always present, highly specific and interspecifically variable, with a long range of shapes and sizes and presenting or not a flat lamella. Petiolar carinae are usually present and developed: anterolateral and anterodorsal carinae are often present, while dorsolateral carinae, when present, are weak and not surpassing the petiolar spiracle (except for the heavily sculptured A. susanae ). A few heavily sculptured species may present petiolar posterolateral and/or posterodorsal carinae.

Femora and tibiae with their distal halves swollen (maximum width/minimum width~3–4 typically), except for the koloi species group, in which femora and tibiae have cylindrical shapes.

Setae are always present, usually unequal, with very long and shorter setae, from semierect to erect in the whole body. A few species may have reclined and similar in length setae (e.g. A. mvuvii , A. jacki ). Funiculus is always coated with short, dense pubescence and semierect short setae, slightly longer than funiculus width. Pubescence is absent in the rest of the body, except for A. steindachneri Mayr, 1901, which presents short, dense pubescence on lateropropodeum and petiolar sides.

SPECIES GROUPS: AFROTROPICAL VS. PALAEARCTIC, ASIAN AND AUSTRALASIAN FAUNA

West Palaearctic

The Western Palaearctic Aenictus fauna lacks a global taxonomic revision and comprises four species: A. arabicus Sharaf & Aldawood, 2012; A. dlusskyi Arnol’di, 1968; A. rhodiensis Menozzi, 1936 and A. vaucheri Emery, 1915.

JAITRONG & RUANGSITTICHAI (2018) have modified the initial definition of the wroughtonii group given in JAITRONG & YAMANE (2011) to include species with short scapes and listing A. arabicus and A. rhodiensis into that group.

Asia, Indomalaya and Australasia

WILSON (1964) defined five species groups for the Indo-Australian area based on morphological characters. These groups were modified and refined for the Eastern Oriental, Indo-Australian and Australasian regions ( JAITRONG & YAMANE, 2011; JAITRONG & HASHIMOTO, 2012; JAITRONG & RUANGSITTICHAI, 2018). The current definition includes twelve groups and comprises the whole distribution range for the genus excluding the four Palaearctic species and the Afrotropical region.

Twelve Afrotropical species were included in WILSON (1964), and though these species were not included in the final groups, a brief statement was given on the African fauna:

“On examining the numerical data on African Aenictus […], it can be seen that the following form a closely knit group: asperivalvus, mariae , mentu, rotundatus , steindachneri and weissi . These, in turn are allied to the ceylonicus group of species in Asia, especially peguensis of Burma” [ WILSON, 1964: 436].

The inclusion of asperivalvus in the analysis must be considered as an error, as it’s only known from males. GOTWALD & BARR (1988) follow Wilson’s definition and include all the Afrotropical species studied into this group. Further redefinition of the group ( JAITRONG & YAMANE, 2011) leave aside almost all of the Afrotropical species. Also note that all the mentioned species but mentu are included in this revision under the rotundatus species group.

Lacking molecular and/or genetic evidence, the morphological information suggests that the relation of Afrotropical and Asian groups appears to be weak. This is suggested from the following characters:

• the absence of the “ Typhlatta spot” in any Afrotropical species excludes the currax, inflatus, laeviceps and leptotyphlatta groups;

• scapes relatively short-medium sized (usually SIL<85) and never reaching posterolateral corner of head excludes hottai and pachycerus groups. This is true except for the Afrotropical group decolor with relatively long scapes (SIL 85-100), but their characteristic mandibular morphology is not found in any Asian species;

• 10 segmented antennae excludes silvestrii group;

• absence of a conspicuous row of denticles at the basal margin of mandibles excludes minutulus (formerly piercei) group ( JAITRONG & HASHIMOTO, 2012);

• the absence of a mesonotum-mesopleuron ridge excludes the philippinensis group;

• the lack of a masticatory margin with a large basal tooth excludes javanus group.

The remaining two groups (ceylonicus and wroughtonii) deserve a more detailed analysis.

The ceylonicus group comprises the species, among other characteristics “with mandibles closed, a gap present between mandibles and anterior margin of clypeus; anterior clypeal margin weakly concave or almost straight, lacking denticles” ( JAITRONG & YAMANE, 2010, see also LIU et al., 2015). Two Afrotropical species have linear mandibles that do not close against the clypeus ( A. eugenii and A. mvuvii ) but both species present two small clypeal denticles between ( eugenii ) or just below ( mvuvii ) the antennal insertions.

The wroughtonii group (clypeus with a row of triangular teeth and poorly developed subpetiolar process) has been recently redefined ( JAITRONG & RUANGSITTICHAI, 2018) to include the species with short scapes. Under this new definition, several Afrotropical species could belong to this group except for the fact that very similar species may or may not present or not developed subpetiolar processes, even in series from the same nest in some species.

The above data strongly suggests that the similarities of the Afrotropical groups with their Asian counterparts is more of convergent nature, and there is substantial morphological differentiation between the groups in both biogeographical regions. Therefore, instead of expanding the definitions of ceylonicus and wroughtonii groups, and along with the other clearly differentiated Afrotropical five groups, I prefer to define the new eugenii and rotundatus groups for the Afrotropical species until genetic or molecular studies are available and the real affinities can be properly established.

Despite this decision, these two pairs of species groups seem to be the best candidates for a link between Asian and Afrotropical faunas.

AFROTROPICAL SPECIES GROUPS: DEFINITION AND IDENTIFICATION TIPS

Unfortunately, genetic data for the reviewed species were not available for this study and building a phylogeny to define species groups based on it was not possible. From this point of view, the species groups defined in this paper should be considered as informal and preliminary, waiting for complementary studies.

This revision proposes organizing the Afrotropical species in seven groups, is based mainly on mandibular and clypeal shape. These two characters alone seem to be good enough to separate the species groups in a robust manner. The A. koloi group is defined based on its cylindrical legs and sculptured heads (which are swollen and glassy smooth respectively in the other groups). The rotundatus group is also separated into two species complexes based on SIL index.

Besides the cited clypeal and mandibular shape, the most helpful characters to differentiate species are subpetiolar process, propodeal shape, scape length relative to head length (SIL), sculpture and setation. When mounting specimens it is important to lift the abdomen upwards and push the third pair of legs forward, so that the subpetiolar process is visible.

SYNOPSIS OF AFROTROPICAL SPECIES

Only species with described worker caste. [Q] ‘Queen also described’

asantei group

asantei Campione, Novak & Gotwald, 1983 [Q]

decolor group

bidentatus Donisthorpe, 1942 stat. rev.

decolor ( Mayr, 1879) [Q]

= batesi Forel, 1911

villiersi Bernard, 1953

eugenii group

eugenii Emery, 1895 [Q]

=brazzai Santschi, 1910 syn. nov.

= eugenii caroli Forel, 1910 syn. nov.

= eugeniae v. kenyensis Santschi, 1933

= eugenii henrii Santschi, 1924 syn. nov.

mvuvii sp. nov.

koloi group

koloi sp. nov.

susanae sp. nov.

xegi sp. nov.

popeyei group

popeyei sp. nov.

rixator group

mentu Weber, 1942

rixator Emery, 1901

rotundatus group

mariae species complex

boltoni sp. nov.

hitai sp. nov.

mariae Emery, 1895

= mariae natalensis Emery, 1901 syn. nov.

steindachneri Mayr, 1901

rotundatus species complex

congolensis Santschi, 1911 [Q]

guineensis Santschi, 1924

jacki sp. nov.

nyuyi sp. nov.

rotundatus Mayr, 1901

=furibundus Arnold, 1959 syn. nov.

= rotundatus merwei Santschi, 1932 syn. nov.

ugaduwensis sp. nov.

weissi Santschi, 1910 [Q cited, not described]

KEY TO SPECIES (WORKERS)

1 Head glassy smooth ( Fig. 2 A ); femora with their distal halves expanded ( Fig. 2 C ) (Maximum width / minimum width ~ 3–4) .............................................................................. 2

- Head alutaceus to heavily reticulated, matt ( Fig. 2 B ); femora subcylindrical ( Fig. 2 D ) (Maximum width / minimum width <2) ........................................................... 7 ( koloi group)

2 (1) Mandibles either linear or triangular, never with either a large blunt, rounded basal tooth nor with its basal half expanded and semi-spherical ( Fig. 1 A, 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 ( Fig. 1 E, F ) ...................................................................................................... 6

3 (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 ( Fig. 1 C, 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 ( Fig. 1 A, G, H ) ......... ................................................................................................................................................... 4

4(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 ( Fig. 1 G ) ............................................. ( asantei group), one species, 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 ( Fig. 1 A, H ) .................... 5

5 Mandibles linear, with three or four defined teeth. Clypeus reduced to a thin line, virtually not visible in frontal view ( Fig. 1 H ) ............................................................. 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 ( Fig. 1 A ) .................................................... 13 ( rotundatus group)

6 (2) Mandibles with basal half expanded and semi-spherical, surrounded by a thin cutting edge ( Fig. 1 E ) ........................................................... popeyei group (one species, popeyei sp. nov.)

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

KEY FOR koloi GROUP

7 (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 ( Fig. 22 C ) ................ .......................................................................................................................... susanae sp. nov.

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

8 (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 ( Fig. 20 C ); smaller size (HW<0.60) ...................................................................................... koloi sp. nov.

- Subpetiolar process very developed, subrectangular and followed by a rectangular lamella usually inclined 45 degrees forward, the whole process clearly larger than the prora ( Fig. 24 C ); larger size (HW>0.65) ........................................................................................... xegi sp. nov.

KEY FOR decolor GROUP

9 (8) Scapes relatively shorter, slightly surpassing three quarters of head length when laid back (SIL<80), smaller size (HL<0.70, WL<1.15) ........................................................... 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 (9) Scapes reaching three quarters of the head length when laid back (80<SIL<95). Subpetiolar process subrectangular, volume slightly smaller than petiolar dome and of similar shape, displaced forward ( Fig. 7 C ) ............................................................................... decolor

- Scapes almost reaching the occipital border when laid back (SIL>95). Subpetiolar process small and shaped as a quarter of ellipse, with its vertical line anteriorly located ( Fig. 9 C ) ....... ......................................................................................................................................... villiersi

KEY FOR eugenii GROUP

11 (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 ( Fig. 18 A ); mesosoma covered with subequal reclined short setae, shorter than petiole height ( Fig. 18 C ). Size clearly smaller (0.47<HW<0.63) .................................................................................. mvuvii sp. nov.

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

12 (5) Ridge separating dorso and posteropropodeum present and clearly visible projecting from the dorsal propodeal surface ( Fig. 30 C ). Mandibles with three teeth similar in size ..... rixator

- Ridge separating dorso and posteropropodeum absent, so dorso and posteroprodeum form a smooth continuous surface ( Fig. 28 C ). Mandibles with an apical tooth followed by three smaller denticles ............................................................................................................... mentu

KEY FOR rotundatus GROUP

NOTE: A. rotundatus minima workers with HW<0.46 present SIL = 60, with one single worker presenting a SIL of 59 for HW=0.39. Larger workers always present SIL>62. The minima workers can only be confused with some samples of A. boltoni sp. nov.

13 (5) Scapes relatively very short (SIL<58). If 58 <SIL<62, then setae on the mesosoma semierect to erect, unequal and long mixed with shorter reclinated setae ( Fig. 57 C ) ............... ....................... 14 ( mariae species complex, minima workers of A. rotundatus with HW<0.46)

- Scapes relatively longer (SIL ≥ 60, usually>62). If 58<SIL<62, then setae on the mesosoma reclinated and similar in length ( Fig. 52 C ) .......................... 18 ( rotundatus species complex)

KEY FOR mariae SPECIES COMPLEX

14 (13) SIL 58–60 ....................................................................................................................... rotundatus (part, exceptionally small minima workers with HW<0.46. Larger HW always SIL>62)

- SIL <58, usually SIL <56 ..................................................................................................... 15

15 (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) ( Fig. 39 D ) ....................................................................................... steindachneri

- Lateral surfaces of mesonotum, propodeum, petiole and postpetiole bare, setation restricted to some occasional isolated setae ( Fig. 54 D ) ............................................................................ 16

16 (15) Dorsopropodeum densely sculptured, punctated-reticulated even in the minima workers as a faint reticulum ( Fig. 35 D , Fig. 34 D ). Dorsopronotum with very dense pilosity, covered with more than 20 white short reclinated setae, without bare zones where cuticle is clearly seen ( Fig. 35 C , Fig. 35 C ) ............................................................................................ hitai sp. nov.

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

17 (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]) ( Fig. 32 C, D ). Western Africa .... boltoni sp. nov.

- 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 ( Fig. 37 C, D ) ............................................................................. mariae

KEY FOR rotundatus SPECIES COMPLEX

18 (13) Setae adpressed everywhere ( Fig. 41 A, C ). Clypeus with a row of very conspicuous long, conical teeth, much longer than wide, the two central smaller than the rest ( Fig. 41 ). Subpetiolar process subrectangular, clearly lower than long, oriented 45° forward, mostly digit shaped ( Fig. 41 C ) ................................................................................................... congolensis

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

19 (18) Scapes very long (SIL>80). Meatanotal groove in profile wide, rounded, U-shaped ( Fig. 54 C ) ........................................................................................................... nyuyi sp. nov.

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

20 (19) Setae on dorsal surface of mesosoma reclined, very abundant and with similar length [ Fig. 32C , Fig. 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 ( Fig. 32 A , Fig. 37 A ) ............................................................................................................................... jacki sp. nov.

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

21 Head subquadrate (CI>95) ( Fig. 59 A ) with stouter mesosoma (WL/PRW<250) ( Fig. 59 C, D ) ........................................................................................................ ugaduwensis sp. nov.

- Head more elongated (CI<93) ( Fig. 61 A ) with more slender mesosoma (WL/PRW>270) ( Fig. 61 C, D ) ......................................................................................................................... 22

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

- Dorso and posteropropodeum not separated by a horizontal ridge, so having a continuous smooth transition into each other ( Fig. 44 C ); 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 ( Fig. 44 D ). Subpetiolar process rounded and usually with a triangular to ellipsoidal lamella .. ................................................................................................................................................. 22

22 (21). PL/PH>1.35. If 1.25<PL/PH<1.35 then 26.225*PH/PL+8.680WL/SL-40.524<0. West Africa ......................................................................................................................... guineensis

- PL/PH<1.25. If 1.25<PL/PH<1.35 then 26.225*PH/PL+8.680WL/SL-40.524>0. East and Southern Africa ........................................................................................................ rotundatus

Figures

Fig. 2. Head sculpture and femora shapes. A, C, Aenictus guineensis (CASENT0876634). B, Aenictus xegi sp. nov. (NHMUK012849243). D, Aenictus susanae sp. nov. (CASENT0406729).

Fig. 1. Mandibular and clypeal shapes for the different species groups. A, gr. rotundatus (Aenictus guineensis, CASENT0876634). B, gr. koloi (Aenictus koloi, sp. nov., KGCOL00552). C, gr. eugenii (Aenictus eugenii, CASENT0235822). D, gr. eugenii (Aenictus mvuvii, sp. nov., CASENT0350555). E, gr. popeyei (Aenictus popeyei, sp. nov., CASENT0810234). F, gr. decolor (Aenictus decolor, CASENT0317077). G, gr. asantei (Aenictus asantei, NHMUK012849241). H, gr. rixator (Aenictus rixator, CASENT0907030).

Fig. 22. Aenictus susanae sp. nov., holotype (CASENT0406728). A, head, dorsal view. B, habitus, lateral view. C, mesosoma, petiole and postpetiole, lateral view. D, mesosoma, petiole and postpetiole, dorsal view.

Fig. 20. Aenictus koloi sp. nov., paratype (KGCOL00552). A, head, dorsal view. B, habitus, lateral view. C, mesosoma, petiole and postpetiole, lateral view. D, mesosoma, petiole and postpetiole, dorsal view. E, mandibles and clypeus, dorsal view.

Fig. 24. Aenictus xegi sp. nov., holotype (NHMUK012849243). A, head, dorsal view. B, habitus, lateral view. C, mesosoma, petiole and postpetiole, lateral view. D, mesosoma, petiole and postpetiole, dorsal view. E, mandibles and clypeus, dorsal view.

Fig. 7. Aenictus decolor, worker (CASENT0317077). A, head, dorsal view. B, habitus, lateral view. C, mesosoma, petiole and postpetiole, lateral view. D, mesosoma, petiole and postpetiole, dorsal view. E, mandibles and clypeus, dorsal view.

Fig. 9. Aenictus villiersi, syntype (CASENT0915327). A, head, dorsal view. B, habitus, lateral view. C, mesosoma, petiole and postpetiole, lateral view. D, mesosoma, petiole and postpetiole, dorsal view.

Fig. 18. Aenictus mvuvii sp. nov., holotype (CASENT0350555). A, head, dorsal view. B, habitus, lateral view. C, mesosoma, petiole and postpetiole, lateral view. D, mesosoma, petiole and postpetiole, dorsal view. E, mandibles and clypeus, dorsal view.

Fig. 11. Aenictus eugenii, worker (CASENT0235822). A, head, dorsal view. B, habitus, lateral view. C, mesosoma, petiole and postpetiole, lateral view. D, mesosoma, petiole and postpetiole, dorsal view.

Fig. 30. Aenictus rixator, holotype (CASENT0907030). A, head, dorsal view. B, habitus, lateral view. C, mesosoma, petiole and postpetiole, lateral view. D, mesosoma, petiole and postpetiole, dorsal view. E, mandibles and clypeus, dorsal view.

Fig. 28. Aenictus mentu, syntype (MCZC:ENT:26131). A, head, dorsal view. B, habitus, lateral view. C, mesosoma, petiole and postpetiole, lateral view. D, mesosoma, petiole and postpetiole, dorsal view.

Fig. 57. Aenictus rotundatus, major worker (CASENT0249285). A, head, dorsal view. B, habitus, lateral view. C, mesosoma, petiole and postpetiole, lateral view. D, mesosoma, petiole and postpetiole, dorsal view.

Fig. 52. Aenictus jacki sp. nov., paratype (CASENT0840036). A, head, dorsal view. B, habitus, lateral view. C, mesosoma, petiole and postpetiole, lateral view. D, mesosoma, petiole and postpetiole, dorsal view.

Fig. 39. Aenictus steindachneri, syntype (CASENT0919642). A, head, dorsal view. B, habitus, lateral view. C, mesosoma, petiole and postpetiole, lateral view. D, mesosoma, petiole and postpetiole, dorsal view.

Fig. 54. Aenictus nyuyi sp. nov., paratype (KGCOL00562). A, head, dorsal view. B, habitus, lateral view. C, mesosoma, petiole and postpetiole, lateral view. D, mesosoma, petiole and postpetiole, dorsal view.

Fig. 35. Aenictus hitai sp. nov., major worker (CASENT0777863). A, head, dorsal view. B, habitus, lateral view. C, mesosoma, petiole and postpetiole, lateral view. D, mesosoma, petiole and postpetiole, dorsal view.

Fig. 34. Aenictus hitai sp. nov., minor, holotype (NHMUK012849306). A, head, dorsal view. B, habitus, lateral view. C, mesosoma, petiole and postpetiole, lateral view. D, mesosoma, petiole and postpetiole, dorsal view.

Fig. 32. Aenictus boltoni sp. nov., holotype (NHMUK012849298). A, head, dorsal view. B, habitus, lateral view. C, mesosoma, petiole and postpetiole, lateral view. D, mesosoma, petiole and postpetiole, dorsal view.

Fig. 37. Aenictus mariae, worker (CASENT0256570). A, head, dorsal view. B, habitus, lateral view. C, mesosoma, petiole and postpetiole, lateral view. D, mesosoma, petiole and postpetiole, dorsal view.

Fig. 41. Aenictus congolensis, worker (CASENT0066799). A, head, dorsal view. B, habitus, lateral view. C, mesosoma, petiole and postpetiole, lateral view. D, mesosoma, petiole and postpetiole, dorsal view.

Fig. 44. Aenictus guineensis, major worker (CASENT0876634). A, head, dorsal view. B, habitus, lateral view. C, mesosoma, petiole and postpetiole, lateral view. D, mesosoma, petiole and postpetiole, dorsal view. E, mandibles and clypeus, dorsal view.

Fig. 59. Aenictus ugaduwensis sp. nov., holotype (NHMUK012849272). A, head, dorsal view. B, habitus, lateral view. C, mesosoma, petiole and postpetiole, lateral view. D, mesosoma, petiole and postpetiole, dorsal view.

Fig. 61. Aenictus weissi, worker (CASENT0317076). A, head, dorsal view. B, habitus, lateral view. C, mesosoma, petiole and postpetiole, lateral view. D, mesosoma, petiole and postpetiole, dorsal view.