Key to Tetramorium schaufussii species complex

This worker key is based on: [[Media:Hita Garcia, F. & Fisher, B.L. 2014. The hyper-diverse ant genus Tetramorium in the Malagasy region ‑ taxonomic revision of the T. naganum, T. plesiarum, T. schaufussii, and T. severini species.pdf|Hita Garcia, F. & Fisher, B.L. 2014. The hyper-diverse ant genus Tetramorium Mayr (Hymenoptera, Formicidae) in the Malagasy region ‑ taxonomic revision of the T. naganum, T. plesiarum, T. schaufussii, and T. severini species groups. ZooKeys 413, 1–170 (doi: 10.3897/zookeys.413.7172).]]

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 * Tetramorium schaufussii  species group (species list, diagnosis, distribution, etc.)
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1

 * Petiolar node relatively long and low, in profile around 1.2 to 1.4 times higher than long (LPeI 72–81) and in dorsal view between 1.0 to 1.2 times longer than wide (DPeI 87–98) (Fig. 40A) [Madagascar] . . . . . Tetramorium nassonowii


 * Petiolar node shorter and higher than above, in profile around 1.5 to 2.2 times higher than long (LPeI 45–67) and in dorsal view between 1.1 to 1.5 times wider than long (DPeI 109–154) (Fig. 40B, C) . . . . . 2

2
return to couplet #1
 * Eyes relatively small (OI 20) (Fig. 41A) [Madagascar] . . . . . Tetramorium pseudogladius


 * Eyes usually much larger than above (OI 25–28, rarely OI 22–24) (Fig. 41B, C, D) . . . . . 3

3
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 * Propodeal spines moderate to long (PSLI 22–24) and propodeal lobes relatively well developed, spines and lobes strongly inclined towards each other (Fig. 42A) [Madagascar] . . . . . Tetramorium scutum


 * Character combination never as above, propodeal spines usually shorter than PSLI 18, if longer than PSLI 21, then propodeal spines and lobes not inclined towards each other (Fig. 42B, C, D) . . . . . 4

4
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 * Smaller species (HW 0.46–0.49; WL 0.58–0.64); propodeal spines relatively long (PSLI 21–25); petiolar node thinly cuneiform, in profile 2.0 to 2.2 times higher than long (LPeI 45–50); waist segments without long, standing pilosity; body colour whitish yellow to light brown (Fig. 43A) [Madagascar] . . . . . Tetramorium rala


 * Character combination never as above, larger species (HW 0.53–0.84; WL 0.70–1.20) with relatively short propodeal spines/teeth, which are always shorter than above (PSLI 8–18); petiolar node variably shaped but always lower than above, in profile around 1.5 to 1.9 times higher than long (LPeI 52–67); waist segments with or without long, standing pilosity; body colour variable (Fig. 43B, C, D) . . . . . 5

5
Larger species (HW 0.71–0.84; WL 1.00–1.20); antennal scapes relatively long (SI 77–82); dorsum of promesonotum with seven to ten pairs of long, standing hairs; waist segments usually without any long, standing pilosity, rarely one pair present on petiole or postpetiole (Fig. 44A) [Madagascar]. . . . . Tetramorium obiwan
 * return to couplet #4


 * Character combination never as above; antennal scapes always shorter (SI 66–75); usually smaller species, but if body size in range above HW 0.70 and WL 1.00, then both waist segments with several pairs of long, standing hairs (Fig. 44B, C, D) . . . . . 6

6
return to couplet #5
 * Dorsum of promesonotum usually with two to four pairs of long, standing hairs; propodeum and waist segments without any standing pilosity (Fig. 45A) [Madagascar] . . . . . Tetramorium sikorae


 * Dorsum of promesonotum always with more than four pairs of long, standing hairs; waist segments always with standing pilosity (Fig. 45B, C, D) . . . . . 7

7
return to couplet #6
 * Bicoloured species, head and/or mesosoma very dark brown to black and strongly contrasting with yellow to light brown waist segments and gaster (rarely also mesosoma) (Fig. 46A, B) [Madagascar] . . . . . Tetramorium xanthogaster (in part - also )


 * More or less uniformly coloured species, sometimes gaster darker than rest of body (Fig. 46C, D) . . . . . 8

8
return to couplet #7
 * Head relatively long and thin (CI 86–90); clypeus always with well-developed and regular median longitudinal ruga (Fig. 47A, B) [Madagascar, Reunion] . . . . . Tetramorium schaufussii


 * Head relatively shorter and thicker (CI 92–95); clypeus usually with either median area unsculptured or traces of median ruga present but weakly developed and irregularly shaped (Fig. 47C, D), very rarely with a well-developed longitudinal ruga (Fig. 47E) . . . . . 9

9
return to couplet #8
 * Frontal carinae relatively better developed; cephalic dorsum between frontal carinae with nine to thirteen relatively regularly shaped, mostly unbroken rugae; propodeal spines short to medium-sized (PSLI 18–22) (Fig. 48A, B) [Madagascar] . . . . . Tetramorium monticola


 * Frontal carinae relatively more weakly developed; cephalic dorsum between frontal carinae with six to ten relatively irregularly shaped, often meandering or broken rugulae; propodeal spines reduced to short to very short teeth/denticles (PSLI 8–16) (Fig. 48C, D) . . . . . 10

10
return to couplet #9
 * Relatively smaller species (HW 0.54–0.69; WL 0.72–0.92); dorsum of propodeum usually with long, standing pilosity (Fig. 49A) [Madagascar] . . . . . Tetramorium xanthogaster (in part - also )


 * Relatively larger species (HW 0.69–0.79; WL 1.01–1.10); dorsum of propodeum without any long, standing pilosity (Fig. 49B) [Madagascar] . . . . . Tetramorium merina