Identification key to species in the Tetramorium solidum group (workers)

1. Body with branched pilosity (Fig. 2C) ................................................... T. rothschildi (Forel, 1907) – Body either lacking pilosity or with simple pilosity (Fig. 2 A–B, D–I)..........................................2

2. Dorsum of mesosoma in profile without any erect hairs, with appressed pubescence only (Fig. 2 D–H)........................................................................................................................................3 – Dorsum of mesosoma in profile with erect hairs (Fig. 2 A–B, I).............................................14

3. Body with short, broad, blunt, much flattened and strongly appressed glittering silvery hairs (Fig. 2 D–F)....................................................................................................................................4 – Body without such hairs, only with sparse simple appressed pubescence (Fig. 2 G–H)...............6

4. Appressed pubescence long, dense and strap-like, hairs often overhanging one another (Fig. 2E) ............................................................................................................ T. galoasanum Santschi, 1910 – Appressed pubescence sparse and spaced out, not strap-like and not overlapping (Fig. 2 D–E)...5

5. The base of the first gastral tergite in profile forming a thick, laterally projecting downcurved flange, which obscures the tergosternal suture basally and base of the sternite; reddishbrown or red species (Fig. 3A) ........................................................ T. setuliferum Emery, 1895

– The base of the first gasteral tergite in profile not projecting as above, the tergosternal suture and base of the sternite clearly visible; blackish brown to black species (Fig. 3B) ....................... ......................................................................................................................... T. clunum Forel, 1913

6. In dorsal view both waist segments much broader than long and transverse, especially postpetiole extremely broadened with very well developed alar extensions making it approximately as broad as pronotum (Fig. 3C) ............................................................ T. grandinode Santschi, 1913

– Waist segments, especially the postpetiole never shaped as above; if postpetiole with small alar extensions, then petiole not broadened (Fig. 3 D–F)........................................................................7

7. Propodeum unarmed, lacking propodeal spines (Fig. 3G) .................. T. jordani Santschi, 1937 – Propodeum armed with a pair of spines (Fig. 3 H–I).................................................................8

8. Petiole in dorsal view broadened with lateral extensions on the sides (Fig. 3D) ............................ ................................................................. T. lerouxi Mbanyana, Robertson & Hita Garcia sp. nov. – Petiole in dorsal view without any lateral extensions as above (Fig. 3 E–F)....................................9

9. In full-face view head narrower in front of eyes than behind eyes (Fig. 3J) ...................................... ................................................................................................................ T. barbigerum Bolton, 1980 – In full-face view head broader in front of eyes than behind the eyes, or same width (Fig. 3 K–M)...10

10. In profile posterodorsal corner of petiolar node sharply angled and slightly projecting posteriorly (Fig. 3N) ................................................ T. duncani Mbanyana, Robertson & Hita Garcia sp. nov.

– In profile posterodorsal corner of petiolar node rounded or rectangular but not sharply angled as above (Fig. 3 O–P)............................................................................................................................11

11. Head broader in front of eyes than behind eyes (Fig. 3K) ............... T. pogonion Bolton, 1980 – Head same width in front of eyes as behind eyes (Fig. 3 L–M).............................................12

12. Dorsum of mesosoma completely longitudinally or irregularly rugulose/rugose (Fig. 4A) ........... .................................................................................................................... T. signatum Emery, 1895

– Dorsum of mesosoma either predominantly shiny with only superficial punctate sculpture, or densely reticulate punctate, often with few faint longitudinal costulae, median area of mesosoma usually very weakly sculptured (Fig. 4B)..................................................................13

13. Propodeal spines short, broad and acute apically (PSLI 4–8) (Fig. 3H) ... T. glabratum Stitz, 1923 – Propodeal spines long and narrow (PSLI 16–23) (Fig. 3I) ........................ T. rufescens Stitz, 1923

14. Abundant erect hairs on all dorsal surfaces of head and body (Fig. 2 D–E)........................15 – Only one to four pairs of hairs present on dorsum of mesosoma (Fig. 2L).................................18

15. Antennal scapes with erect hairs (Fig. 4C)...................................................................................16 – Antennal scapes without erect hairs, only with flattened pubescence (Fig. 4D)........................17

16. Dorsal surface of mesosoma with strongly developed irregular reticulate sculpture; colour orange (Fig. 4E, G) ................................................................................................ T. peringueyi Arnold, 1926

– Dorsal surface of mesosoma with short longitudinal rugulae; ground sculpture mainly smooth and shiny with peripheral patches of fine, superficial reticulations; colour uniformly black (Fig. 4F, H) ............................... T. margueriteae Mbanyana, Robertson & Hita Garcia sp. nov.

17. Propodeum armed with acute spines (PSLI 10–16); colour light brown, with gaster a little bit darker compared to mesosoma (Fig. 4I) .................................................. T. dichroum Santschi, 1932

– Propodeum with short propodeal teeth (PSLI 6); colour reddish brown, with gaster black (Fig. 4J) ........................................... T. brigitteae Mbanyana, Robertson & Hita Garcia sp. nov.

18. Propodeum with elongate and acute spines (PSLI 17–21) (Fig. 4K) .... T. solidum Emery, 1886 – Propodeum with short triangular teeth (PSLI 5–9) (Fig. 4L) .......................................................... .................................................................... T. aisha Mbanyana, Robertson & Hita Garcia sp. nov .