
They are about the same size as Messor Barbarus, the queen is 0,9-1 cm long and workers are 0,4-0,8cm. Could be bigger though, i think i saw bigger ones in nature.
They live(d) in a desert-like place with sand, rocks and a some plants here and there, about 500m above sea-level. They were found living under a rock in sand by me.
However, problems have occurred. When i collected them, they had around 20 workers, brood and the queen, but today when i checked on them, half of the workers were dead, and all of the brood are gone.
I kept them in a empty water bottle for about a week and after that i placed the bottle in a tank and added a fresh test-tube in there, too. They are now living in the test-tube without access to the arena, because of the deaths.
So if someone could identify these ants (I'm pretty sure they are Messor species becuase of their looks and i saw their kind carrying seeds in nature), and also give me an idea what could be the cause of all the deaths?
EDIT: A picture of the same species in nature:













