Key to Messor species groups

This key is slightly modified from Cagniant & Espadaler (1997)

1

 * Long “J” shaped hairs forming a “basket” (psammophore) present on gula and mandibles .....2


 * Gula and mandibles with inequal, straight, short and randomly disposed hairs .....5

2
return to couplet .....1


 * Black or dark brown. Head, alitrunk, petiole and postpetiole deeply striated. Gaster reticulated. First segment of the funiculus rounded and slghtly smaller than the second segment. Tibiae in all legs with a pair of pectinated spurs. Big ants TL 4.8-13.6 mm, HW max 3.4 mm …..arenarius group


 * First segment of the funiculus more or less rectangular and flattened, longer than the second segment. Tibiae of the second and third pair of legs with two simple spurs .....3

3
return to couplet .....2


 * Whole body from yellow to yellow brown. Propodeum rounded. Majors can reach a TL of 10 mm (HW max 3,5 mm) …..rufotestaceus group


 * Black or bicoloured. Propodeum forming an angle, or armed with teeth or spines Major ants do not reach TL 9.5 mm (HW max 2,7 mm) .....4

4
return to couplet .....3


 * Scape with a scale on its base …..lobicornis group


 * Scape without a scale on its base …..aegyptiacus group

5
return to couplet .....1


 * Clypeus emarginated. Head in frontal view with erect quetae present all over the head profile. Striated sculpture well developed …..structor group


 * Clypeus not emarginated. Head in frontal view with erect quetae present at the occiput, but not over the genae. Sculpture not so clearly developed, with heads and sometimes alitrunk, petiole and postpetiole smooth .....6

6
return to couplet .....5


 * First funicular segment twice as long as the second. Seen from the interior part, profile rectangular, flat and clearly wider than the second …..antennatus group


 * First funicular segment at most 1.5 times longer than the second …..barbarus group