The Bullet Ant (Paraponera clavata) is probably the most infamous ant in the world.
This conspicuous insect is known for an unusually painful sting, similar to that of getting shot with a gun.
It is considered to be the worst pain caused by an insect and the pain can last up to 24 hours.
Bullet Ants are only found in low-elevation forests in Central or South America, from Honduras south to Paraguay.
It is not the only big rainforest ant, however, and other species are frequently mistaken for it.
Bullet Ants are not just large, they are massive: 2 - 3 cm (over an inch long!).
Bullet Ants have a pair of blunt horns on the first segment of the thorax (clearly shown on the photo). No other ant this size has the horns.
In addition, the waist of the Bullet Ant has a sharp, forward-leaning triangular node.

Ants are the world’s most ecologically important insects, both in terms of biomass and diversity of ecosystem services.
About 15,000 species inhabit almost all terrestrial habitats, including deserts and high mountains.
Ants are social insects characterised by a highly sophisticated division of labour: different individuals carry out different functions.

Dominik Hofer, a Swiss nature photographer and identifier on several animal website fora helped me identifying this species.

Old Buenavista Road, Buenaventura area, Valle del Cauca, Colombia, 14 June 2016