Notoncus

Nests of these common ants are found in open soil or under stones and logs on the ground. They are general predators, foraging on the ground surface. Although active all year, in some areas they can be more active during the winter. They are frequently seen in urban gardens and parks.

Identification
The mandibles have 6 or 7 teeth. The frontal carinae are weakly arched or straight along their entire length (except the extreme forward ends near the antennal sockets, which are curved). The worker caste is only slightly variable in size (weakly polymorphic) and without distinct major and minor workers. The upper surface of the mesosoma between the mesonotum and propodeum is sometimes expanded upwards into a rounded or angular process, or it may be flat.

Notoncus contains two distinct sets of species. One set has a distinct rounded or angular projection extending upwards from the area between the mesonotum and propodeum. This configuration is unique within the Australian formicines (with the exception of a single species of Melophorus) and can be used to identify these species. The other set of species has the upper surface of the mesosoma flat or weakly concave and not set off from the surrounding regions of the mesosoma. These species are similar to Myrmecorhynchus in overall shape and size and can be separated from them by having the frontal carinae straight, and by being only weakly polymorphic and without distinct major and minor workers. They also have only 6 or 7 teeth on the mandibles while all but the largest Myrmecorhynchus workers have between 10 and 13 teeth.

Species by Region
Number of species within biogeographic regions, along with the total number of species for each region.

Nomenclature

 *  NOTONCUS [Formicinae: Myrmecorhynchini]
 * Notoncus Emery, 1895g: 352. Type-species: Camponotus ectatommoides, by original designation.
 * Notoncus senior synonym of Diodontolepis: Brown, 1955d: 477.
 * DIODONTOLEPIS [junior synonym of Notoncus]
 * Diodontolepis Wheeler, W.M. 1920: 53. Type-species: Melophorus spinisquamis, by original designation.
 * Diodontolepis junior synonym of Melophorus: Emery, 1925b: 11.
 * Diodontolepis revived status as genus: Wheeler, W.M. 1935c: 71.
 * Diodontolepis junior synonym of Notoncus: Brown, 1955d: 477.