Aphaenogaster

Aphaenogaster is a genus of myrmicine ants. Almost 200 species have been described. Also, 11 fossil species are known. They live worldwide except from South America and Southern Africa. 
They are often confused with "Pheidole" or "Pheidologeton". These two have major and minor workers, while "Aphaenogaster" has only a single worker caste. "Pheidole" has a 3-segmented club on its antenna. But "Aphaenogaster" has four segments and a larger body size. "Pheidologeton" has a 11-segmented antenna, while the antenna in "Aphaenogaster" is 12-segmented.
They make very thick, easily seen nests with many big entrances in a small place. These entrances can have diameters of up to 4 cm and are up to 30 cm deep. This resulted in their common name funnel ants. These nests can be a bad problem for golfers or on pastures and unsealed airstrips, because the fragile ground easily breaks under pressure.
"Aphaenogaster" gets most of its food from tended aphids on the roots of plants. This explains that they are not commonly seen out of their tunnels. The funnel-shaped openings could play a role in trapping arthropods, which are also eaten.
Although these ants are not aggressive, they will bite when their nest is disturbed.