It is difficult to characterize morphologically. Bolton (2003) placed it in the tribe Solenopsidini, but with multiple exceptions to the diagnostic characters for the tribe. The tribal characters include a bicarinate clypeus and a median clypeal seta. Most "Megalomyrmex" species have a smoothly convex clypeus with no trace of the bicarinate condition, and most have abundant clypeal setae with no distinct or differentiated median seta. In Bolton's (1994) key to genera, "Megalomyrmex" keys in multiple places because of variability in mandibular dentition. Nevertheless, the genus has a distinctive habitus: the antenna is 12-segmented with a 3-segmented club; the general integument is smooth and shiny without coarse sculpture or dull areas; the promesonotum is evenly arched, without promesonotal groove; the propodeum is usually smoothly curved between dorsal and posterior faces, at most with blunt, broad-based tubercles, and never with spines; and the hind tibial spur is simple. In short, the workers look like a "Solenopsis" with "Pheidole" antennae. The mandibular dentition varies from a simple set of 5 similar teeth on the masticatory margin, gradually diminishing in size basally, to a condition with 2 large apical teeth followed by up to 12 small denticles.