Myrmecorhynchus

These small, inconspicuous ants nest in soil or in twigs and vines on shrubs or trees. They are most often encountered while foraging on vegetation or tree trunks. Although they can be locally common they are often overlooked because of their slow movements and arboreal habits. Very little is known concerning their biology.

Identification
The mandibles usually have 10 to 13 teeth, although some large individuals have as few as 6. The frontal carinae are distinctly arched. The upper surface of mesosoma between the metanotum and propodeum is always low and flat or concave and never expanded upwards. The worker caste is variable in size (strongly polymorphic) and has distinct major and minor workers.

Smaller workers of Myrmecorhynchus are identifiable by the large number of teeth on the mandibles. However larger workers have a reduced number of teeth (down to 6 in some individuals) and are similar to some species of Notoncus. These individuals can be identified by the configuration of the frontal carinae which are curved in Myrmecorhynchus while they are straight in Notoncus, and the polymorphic worker caste with distinct majors and minors (Notoncus is weakly polymorphic and without distinct majors and minors). Additionally, some species of Notoncus have an upwards projection on the upper surface of the mesosoma at the metanotal groove. This region of the mesosoma is always flat or concave in Myrmecorhynchus.