Characterized by a pronounced polymorphism among its worker caste, this taxon displays individuals that vary extensively in size, ranging from 4 to 10 mm in length. Their body coloration is predominantly dark brown to charcoal black, giving them a dull, matte appearance. As a key diagnostic anatomical feature of the genus, the dorsal surface of the thorax is adorned with three pairs of spines (pronotal, mesonotal, and propodeal), which distinguishes it from other closely related genera. The head is remarkably wide, featuring prominent occipital spines on the posterolateral corners and robust, serrated mandibles designed specifically for shearing tough plant tissue. Queens are considerably larger, reaching up to 15 mm in length, possessing a muscular, well-developed mesosoma to support flight wings prior to dispersal.

Geographical distribution: Occurs widely across the southern cone of South America. Its presence is highly documented throughout the central and northern regions of Argentina, including major agricultural provinces such as Buenos Aires, Santa Fe, and Córdoba, as well as across the entire territory of Uruguay. Furthermore, its range extends into southern Brazil, particularly within the state of Rio Grande do Sul, and adjacent regions of Paraguay, showing an exceptional tolerance to temperate and subtropical climate regimes.

Habitat: Settles primarily in open grassland biomes, savannas, forest edges, and scrubby steppes. It is a highly adaptable species that thrives in anthropogenically altered environments, making it a common inhabitant of agricultural fields, commercial forestry plantations, pastures, and urban gardens. Their subterranean nests are structurally complex, often reaching several meters in depth, and are marked externally by mounds of loose soil and dry plant debris piled around the main entrance holes.

Feeding: Functions under an obligate mutualistic relationship with a symbiotic basidiomycete fungus belonging to the genus Leucoagaricus. To maintain this vital food source, workers harvest a wide array of vegetation, including leaves, flowers, and tender stems from both monocotyledonous and dicotyledonous plant species. This harvested material is not consumed directly by the ants; instead, it is transported deep into the nest, masticated, and treated with fecal fluids and salivary enzymes to serve as a growth substrate for the fungus. The colony members, particularly the larvae and the queen, feed exclusively on specialized, nutrient-rich structures produced by the fungal mycelium known as gongylidia.

Behavior: Exhibits a complex social structure characterized by division of labor based on physical size, known as caste-based polyethism. Minor workers remain deep within the nest to tend to the brood and cultivate the fungus gardens, while media and major workers are responsible for foraging, nest excavation, and colony defense. They establish highly organized, cleared foraging trails that can extend for over 100 meters from the nest entrance. Although active year-round, foraging peaks during spring and summer; during excessively hot periods, they shift to nocturnal foraging to prevent thermal stress and desiccation. They maintain strict colonial hygiene, keeping specialized waste chambers separate from the fungus gardens to prevent contamination.

Reproduction: Initiates its reproductive cycle via a synchronized nuptial flight, a massive event occurring during late spring or early summer, typically triggered by heavy rainfall followed by warm, humid conditions. During this event, winged virgin queens and males leave their natal nests to mate in flight. Males perish shortly after mating, while the fertilized queen drops to the ground, sheds her wings, and searches for a suitable spot to excavate a small founding chamber. To establish the new colony, the queen relies on a small pellet of the parental fungus that she carries within her infrabuccal pocket, ensuring the survival of the mutualistic fungus for her future offspring.

Conservation status: Has not been evaluated by the IUCN Red List, as its populations are stable, highly abundant, and secure. Rather than being threatened, this species is widely classified as a major agricultural pest within its native range, causing substantial economic damage to citrus crops, forestry, and ornamental plants due to its intense defoliation activities. Its high ecological resilience in human-dominated landscapes ensures its long-term survival.