Megalomyrmex acauna

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Megalomyrmex acauna
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Solenopsidini
Genus: Megalomyrmex
Species group: leoninus
Species: M. acauna
Binomial name
Megalomyrmex acauna
Brandão, 1990

Megalomyrmex-acauna ills.jpg

Megalomyrmex acauna is the only species of this group to be found in cerrados.

At a Glance • Ergatoid queen  


Occipital margin visible in head frontal view; head largest diameter at vertex; non-pedunculate petiole with a round posterior face; anterior slope of postpetiole round.

Brandão (1990) - M. acauana is close to Megalomyrmex balzani from which can be separated by the characters listed in the diagnosis.


Latitudinal Distribution Pattern

Latitudinal Range: -13.61666667° to -16.46666667°.

Tropical South

Distribution based on Regional Taxon Lists

Neotropical Region: Brazil (type locality), Peru.

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.


This species was described from two samples collected in Gustavo Dutra and another locality in the Chapada dos Guimarães, near Cuiabá, Mato Grosso state, Brazil. Dr. Antonio Mayhé-Nunes visited the area recently and discovered that Gustavo Dutra was actually the name of an Agricultural School. The small village is now known as São Vicente, and is located in the county of Santo Antonio do Leverger, some 100 Km East of the state capital, Cuiabá.

Megalomyrmex acauna is the only Leoninus group species recorded in the "cerrados". The Leoninus group is otherwise an entirely Amazonian group. In fact, Prof. Marcelo Tavares sent me recently a sample from the Indian Reserve Tadarimana, Rondonópolis, state of Mato Grosso state, Brazil (16°28'S, 54°38'W). I collected in May 6 to 29, 1996, two colonies of M. acauna in Uruaçu, northwestern Goiás, Brazil (14°17'06"S, 48°55'01"W). Both localities are situated within the "cerrado" biome. The ants live in fairly large colonies that occupy spaces among stones, in a way that is very similar to the most closely related species, M. balzani. In both cases the colonies were found along gallery forests and all attempts to rear them in the lab failed.



The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

  • acauna. Megalomyrmex acauna Brandão, 1990b: 429, figs. 39, 56 (w.) BRAZIL (Mato Grosso).
    • Type-material: holotype worker, 18 paratype workers.
    • Type-locality: holotype Brazil: Mato Grosso, Gustavo Dutra, 25.x.1953 (C.R. Gonçalves); paratypes: 17 workers with same data, 1 worker Mato Grosso, Chapada, vii.1960 (C. Aman).
    • Type-depositories: MZSP (holotype); MCZC, MNRJ, MZSP (paratypes).
    • [Misspelled as acauana by Brandão, 1990b: 431.]
    • Brandão, 2003: 151 (m.).
    • Status as species: Brandão, 1991: 354; Bolton, 1995b: 249; Brandão, 2003: 150; Guénard & Economo, 2015: 227.
    • Distribution: Brazil, Peru.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.



Mandibles smooth; anterior clypeal border straight with median denticle; 3-segmented an­ tenna! club; frontal suture impressed; 18 ocular facets at com pou nd eye largest diameter; promesonotal suture impressed dorsally: mesos­ternum and metasternum without acrotergites; propodeum dorsum not depressed; declivity smooth; epipetiolar carina complete; non-pedun­culate petiole with anteroventral denticle; dorsal margin of petiole in side view straight; ventral face of postpetiole without process; genual plate acuminate.


Brandão (2003) - From Los Angeles County Museum of Natural History, I received a male of M. acauna (undescribed) collected by F.S. Truxal in June 13, 1956, in a locality 24 Km East of Formoso (13°37'S, 48°54'W), Goiás state, Brazil.

Clypeus smooth without anterior denticle; cephalic integument smooth next to the compound eyes: first funicular segment similar in size to scape, second and third smaller; mesonotum with parapsidal furrows impressed, but no notaulus; epipetiolar carina complete; dorsal face of propodeum smooth; petiole compressed dorso-ventrally; petiolar spiracles laterally produced; petiolar and postpetiolar nodes almost indistinct; postpetiole without ventral process; genual plates rounded.

Type Material

Gustavo Dutra, MT, Brasil (14°43'S, 55°39'W); Chapada, MT. Brasil, (15°26'S, 55°45'W).

Holotype (G. Dutra) and 10 paratypes (1 from Chapada, 9 from G. Dutra) at Museu de Zoologia da USP; 2 (G. Dutra) paratypes at Museum of Comparative Zoology, Harvard; 6 paratypes (G. Dutra) at Museu Nacional do Rio de Janeiro.

The types from Gustavo Dutra have been collected by the late Dr. Cincinnato R. Gorn;:alves in October. 25, 1953. The paratype from Chapada has been collected by C. Aman in July. 1960.


The specimen choosen as holotype bears a labels saying "Megalomyrmex nigricornis, sp. n., Borgmeier det." Accordingly I select the name acauna, meaning black horns in the Tupi lan­guage, due to the black scapes of the antennae, that differentiate this species from all others in the group.


References based on Global Ant Biodiversity Informatics

  • Brandão C. R. F. 1990. Systematic revision of the Neotropical ant genus Megalomyrmex Forel (Hymenoptera: Formicidae: Myrmicinae), with the description of thirteen new species. Arquivos de Zoologia (São Paulo) 31: 411-481
  • Brandão C. R. F. 2003. Further revisionary studies on the ant genus Megalomyrmex Forel (Hymenoptera: Formicidae). Papeis Avulsos de Zoologia (São Paulo) 43: 145-159
  • Ulyssea M. A., C. R. F. Brandao. 2013. Catalogue of Dacetini and Solenopsidini ant type specimens (Hymenoptera, Formicidae, Myrmicinae) deposited in the Museu de Zoologia da Universidade de Sao Paulo, Brazil. Papies Avulsos de Zoologia 53(14): 187-209.