Key to Tetramorium dysalum-group species

Based on Hita Garcia and Fisher (2012. The ant genus Tetramorium Mayr (Hymenoptera: Formicidae) in the Malagasy region—taxonomy of the T. bessonii, T. bonibony, T. dysalum, T. marginatum, T. tsingy, and T. weitzeckeri species groups. Zootaxa 3365: 1-123. [[Media:Hita Garcia & Fisher 2012a.pdf|PDF ]])

1

 * Mesosomal dorsum with fine, irregularly arranged rugulae and larger unsculptured areas (Fig. 69) . . . . . Tetramorium ambatovy


 * Mesosomal dorsum with distinct, longitudinally arranged rugae or rugulae (Fig. 70) . . . . . 2

2
return to couplet #1


 * Species with short to moderately sized propodeal spines or teeth (PSLI 19 - 24) (Fig. 71) . . . . . 3


 * Species with long to very long propodeal spines (PSLI 27 - 44) (Fig. 72) . . . . . 5

3
return to couplet #2


 * Petiolar node rounded high nodiform, anterodorsal and posterodorsal margins situated at approximately same height (Fig. 73) . . . . . Tetramorium robitika


 * Petiolar node shape moderately cuneiform with rounded margins, anterodorsal margin situated higher than posterodorsal and dorsum tapering backwards posteriorly (Fig. 74) . . . . . 4

4
return to couplet #3


 * Mandibles unsculptured, smooth and shining, and body colouration dark brown to black (Fig. 75) . . . . . Tetramorium orc


 * Mandibles longitudinally rugose, and body colouration yellow to light brown (Fig. 76) . . . . . Tetramorium mackae

5
return to couplet #2
 * In dorsal view postpetiole always more than 1.6 times wider than petiolar node, usually distinctly so (PPI 168 - 200) (Fig. 77) . . . . . Tetramorium mallenseana


 * In dorsal view postpetiole usually distinctly less than 1.5 times wider than petiolar node (PPI 119 - 152) (Fig. 78) . . . . . 6

6
return to couplet #5
 * Antennal scape comparatively short (SI 64 - 69); anterodorsal margin of petiolar node sharply defined and situated much higher than posterodorsal margin, dorsum strongly tapering backwards posteriorly; mandibles always completely unsculptured (Figs. 79, 80) . . . . . Tetramorium dysalum


 * Antennal scape always longer than above (SI 71 - 78); anterodorsal margin of petiolar node not sharply defined as above, either anterodorsal and posterodorsal margins situated at same height, or posterodorsal margin weakly lower and dorsum only weakly tapering backwards posteriorly; mandibles usually with distinct longitudinal sculpture, rarely unsculptured (Figs. 81, 82) . . . . . 7

7
return to couplet #6


 * Petiolar node high rounded nodiform with anterodorsal and posterodorsal margins at approximately the same height, dorsum not tapering backwards posteriorly (Fig. 83) . . . . . Tetramorium vohitra


 * Petiolar node high rounded nodiform or squamiform, but anterodorsal margin situated higher than posterodorsal margin, dorsum tapering backwards posteriorly (Fig. 84, 85) . . . . . 8

8
return to couplet #7


 * First gastral tergite with decumbent to subdecumbent long hairs (Fig. 86) . . . . . Tetramorium sargina


 * First gastral tergite with erect to suberect long hairs (Fig. 87) . . . . . 9

9
return to couplet #8


 * Eyes comparatively small (OI 19 - 20); propodeal spines very long (PSLI 40 - 41); propodeal lobes very long and spinose; head, mesosoma, waist segments, and gaster of dark brown to black colouration (Figs. 88, 89) . . . . . Tetramorium yammer


 * Eyes larger (OI 21 - 23); propodeal spines long to very long (PSLI 27 - 44); propodeal lobes short and triangular to elongate-triangular and comparatively long, but never spinose and long as above; head, mesosoma, waist segments, and gaster generally of brownish colour, only rarely dark brown (Figs. 90, 91) . . . . . Tetramorium steinheili