Tetramorium

Within their preferred habitats these ants can be very common. They forage individually on the ground, often in large numbers, and are most active during the morning and evening hours. Nests are in soil with a simple entrance, under stones or wood, in rotten wood either on or above the ground, in twigs and under bark. They are general scavengers or predators and seed collecting is common in some species. A few species have been widely spread through human activity.



Worker of T. simillimum from Norfolk Island.

Identification
The area of the clypeus immediately below the antennal sockets is raised into a sharp-edged ridge which forms the lower section of a pit around the base of the antennae. The front margin of the clypeus is weakly convex, flat or weakly concave and covers only the extreme rear section of the mandibles. The lower surface of the petiole is rounded from side to side. The propodeum near the insertion of the petiole is often armed with a pair of spine-like flanges although sometimes the flanges are rounded. The tip of the sting has a triangular to pennant-shaped extension projecting upwards from the shaft (visible only when the sting is extended).

The ridge-like structure of the clypeus immediately below the antennal sockets and the projection on the tip of the sting are unique to Tetramorium and Rhoptromyrmex. They can be separated by (1) the shape of the head (nearly square or rectangular in Tetramorium, somewhat heart-shaped in Rhoptromyrmex), (2) the length of the clypeus (relatively short in Tetramorium, extending forward in Rhoptromyrmex), (3) the nature of the flanges near the insertion of the petiole (often spine-like in Tetramorium, always rounded in Rhoptromyrmex), and (4) the lower surface of the petiole (rounded in Tetramorium, keel-like in Rhoptromyrmex).

Distribution and Habitats
Australian distribution

Regional Species Lists

 * Australia

Keys to Species

 * Australia