Key to Tetramorium marginatum-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. PDF )

1

Mesosomal dorsum unsculptured, generally smooth and shining; body colouration usually a dark brown to black (Fig. 128) . . . . . 2

Mesosomal dorsum irregularly to longitudinally rugulose; body colouration generally yellow, rarely a pale brown (Fig. 129) . . . . . 5

FIGURES 128 & 129. 128. Unsculptured, smooth, and shining mesosomal dorsum of T. valky - CASENT0496394 (Erin Prado 2010). 129. Irregularly to longitudinally rugulose mesosomal dorsum of T. shamshir - CASENT0467696 (Erin Prado 2010).

2

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Head in frontal view distinctly much longer than wide (CI 87 - 90); propodeal spines long (PSLI 26 - 30) (Fig. 130) . . . . . Tetramorium silvicola

Head in frontal view longer than wide to as long as wide, much wider than above (CI 92 - 100); propodeal spines long to very long (PSLI 32 - 52) (Fig. 131) . . . . . 3

FIGURES 130 & 131. 130. Head of T. silvicola in frontal view distinctly much longer than wide - CASENT0042828 (Erin Prado 2010). 131. Head of T. hector in frontal view moderately longer than wide - CASENT0038460 (Erin Prado 2010).

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Petiolar node in profile thickly cuneiform and less anteroposteriorly compressed (LPeI 60 - 66; DPeI 134 - 147) (Fig. 132) . . . . . Tetramorium hector

Petiolar node in profile triangular cuneiform to squamiform and much more anteroposteriorly compressed than above (LPeI 16 - 47; DPeI 189 - 500) (Fig. 133) . . . . . 4

FIGURES 132 & 133. 132. Petiolar node of T. hector in profile with a thickly cuneiform and less anteroposteriorly compressed shape - CASENT0038460 (Erin Prado 2010). 133. Petiolar node of T. valky in profile with a triangular cuneiform and and much more anteroposteriorly compressed - CASENT0496394 (Erin Prado 2010).

4

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Few pairs of hairs present on mesosomal dorsum, but generally restricted to dorsolateral margins of pronotum and mesonotum, rarely some hairs medially present at dorsal border between mesonotum and propodeum (Fig. 134) . . . . . Tetramorium marginatum

Hairs on dorsal mesosoma more abundant than above, scattered throughout whole dorsum, and not restricted to any margin (Fig. 135) . . . . . Tetramorium valky

FIGURES 134 & 135. 134. Mesosoma of T. marginatum in profile with scarce pilosity, which is generally restricted to dorsolateral margins - CASENT0102398 (April Nobile 2005). 135. Mesosoma of T. valky in profile with abundant pilosity, which is not restricted to any margin - CASENT0496394 (Erin Prado 2010).

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Propodeal spines long to extremely long and always distinctly strongly back-curved; frontal carinae moderately developed and either ending at posterior head margin or shortly before; petiolar node in profile high nodiform to weakly cuneiform, not strongly anteroposteriorly compressed dorsally (LPeI 43 - 53; DPeI 163 - 184) (Fig. 136) . . . . . Tetramorium shamshir

Propodeal spines generally long and usually straight-lined, rarely weakly back-curved; frontal carinae often weakly developed and ending between posterior eye margin and posterior head margin, generally closer to posterior eye margin; petiolar node in profile triangular cuneiform and strongly anteroposteriorly compressed dorsally (LPeI 26 - 41; DPeI 195 - 325) (Fig. 137) . . . . . Tetramorium norvigi

FIGURES 136 & 137. 136. Mesosoma and waist segments of T. shamshir in profile, propodeal spines strongly back-curved and petiolar node high nodiform to weakly cuneiform, not strongly anteroposteriorly compressed dorsally - CASENT0467696 (Erin Prado 2010). 137. Mesosoma and waist segments of T. norvigi in profile with triangular cuneiform and strongly anteroposteriorly compressed dorsally petiolar node - CASENT0489037 (Erin Prado 2010).