Mystrium

These ants are rarely encountered and are poorly known. They are presumably predacious, especially of Chilopoda, but this has yet to be confirmed. Specimens have been found under rocks or dry logs on the ground and in leaf litter. They lie motionless when disturbed.

Identification
The mandibles are long and slender, with numerous (always more than 5) teeth which are similar in size and scattered along the inner margins, and with the tips rounded and with very short teeth. The frontal lobes extend only slightly forward of the antennal sockets and do not cover the clypeus when viewed from the front. The petiole has distinct front and upper faces but lacks a rear face, and its attachment to the gaster is broad and approximately the same height as the petiole so that the upper surfaces of petiole and gaster are separated by at most a shallow impression. The head and body have scattered hairs which are broad and rounded (spatulate).

The long, thin mandibles with rounded tips and the spatulate hairs on the head and body, as well as the shape of the head, are unique to these ants and will allow their ready identification.

Biology
Species of the genus in Madagascar show two distinct reproductive strategies and relevant colony structures (Molet et al. 2006). In some species (e.g. Mystrium rogeri) each colony has a single dealate queen with a larger thorax than workers but with mandibles similar to those of the workers. In colonies of other species (e.g. “M. `red`” in Molet et al. 2006) winged queens are missing and half of the female adults belong to wingless reproductives which are smaller and allometrically distinct from workers. (Bihn & Verhaagh 2007)

Castes


Worker of M. camillae from the Northern Territory, Australia.

Nomenclature

 *  MYSTRIUM [Amblyoponinae]
 * Mystrium Roger, 1862a: 245. Type-species: Mystrium mysticum, by monotypy.

Additional References

 * [[Media:Bihn & Verhaagh 2007.pdf|Bihn, J.H. & Verhaagh, M. 2007. A review of the genus Mystrium in the Indo-Australian region. Zootaxa 1642: 1-12. PDF]]


 * Roger, J. (1862) Einige neue exotische Ameisen-Gattungen und Arten. Berliner Entomologische Zeitschrift, 6: 233–254.