Megalomyrmex ayri

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

Megalomyrmex ayri casent0902327 p 1 high.jpg

Megalomyrmex ayri casent0902327 d 1 high.jpg

Specimen Labels

Specimens collected by W. L. Brown Jr. at Faz. Junqueira Vilela came from a nest collected at 3 km east of the farm house in the forest. The paratypes from Vilhena came from a polygynous colony found by Dra. Ana Harada within the litter near a small stream in the forest. (Brandão 1990)


Workers from Megalomyrmex goeldii and M. ayri are very similar, but the shape of the clypeus and size clearly separate them. Queens are more di­verse and can be distinguished by the ocelli (only the anterior one is developed in M . goeldii) and by the given measurements.


Latitudinal Distribution Pattern

Latitudinal Range: -3.133333333° to -21.16666667°.

Tropical South

Distribution based on Regional Taxon Lists

Neotropical Region: Brazil (type locality).

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.


Brandão (2003) - Dr. Heraldo Vasconcellos collected two workers of Megalomyrmex ayri at Km 72, BR 174, Manaus, Amazonas state, Brazil (03°08’S, 60°01’W), in March 1990 (# 4642). A.B. Casimiro collected a worker and a gyne of M. ayri also in Manaus (# 4832 – Rs 2108 – E3). These are the first records of the species in Central Amazon, and the first records after the description of the species by Brandão (1990). Regarding the Modestus species group, only Megalomyrmex wallacei was previously recorded in the Amazonian basin. Megalomyrmex ayri appears to be uncommon in Manaus, as this locality has been intensively collected in recent years by several colleagues, and only these two samples have turned up thus far.

J. Delabie (CEPLAC, Itabuna, Bahia state, Brazil) sent me for study material collected in three localities in eastern Bahia state, Brazil: 3 alate gynes and a worker (# 4733) in Cachoeira, collected by G. Santos, in December 11, 1993, a worker from Ubatã (14°13’32”S, 39°27’56”W), collected by J.C.S. Carmo in December 27, 1996, and a worker from Ilhéus (# 4544B), collected by A.B. Casimiro in August 25, 1992. Workers of these three samples fit the definition of M. ayri since they show a clear suture between anepisternun and katepisternun. However, the Cachoeira gynes are problematically assigned as they present smooth mandibles. Also all other M. ayri samples come from Amazonian localities. For this reason, it is preferable to wait for more Bahian material before applying a name to these samples.



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

  • ayri. Megalomyrmex ayri Brandão, 1990b: 420, figs. 1, 12, 26, 36 (w.q.) BRAZIL (Mato Grosso, Rondônia).
    • Type-material: holotype worker, 56 paratype workers, 6 paratype queens.
    • Type-locality: holotype Brazil: Mato Grosso, Utiariti, Rio Papagaio (no collector’s name); paratypes: 20 workers with same data, 10 workers Mato Grosso, Munic. Diamantino, Faz. Junqueira Vilela (W.L. Brown), 3 workers Mato Grosso, Sinop (no collector’s name), 29 workers Rondônia, Vilhena (A. Harada).
    • Type-depositories: MZSP (holotype); BMNH, INPA, MCZC, MZSP (paratypes).
    • Status as species: Brandão, 1991: 354; Bolton, 1995b: 249; Brandão, 2003: 146.
    • Distribution: Brazil.

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



Mandibles smooth, clypeus with concave an­terior border between the feeble carinae, that delimit a median depression; promesonotal su­ture impressed dorsally; faces of propodeum meeting in a gentle angle; declivity either smooth or with one rugosity around the foramen; ventral face of petiole with anterior denticle and a longi­ tudinal translucid flange; dorsal margin of petio­lar node slope straight in side view; ventral face of postpetiole with a small globose process.

Pilosity: Long hairs (more than .2mm) all over the body surface; except mandibles, legs and posterior faces of petiole and postpetiole. Small hairs (ca. .1 mm) at mandibles, legs and head.

Color: yellowish-brown.


Mandibles finely striate; ocelli equally devel­ oped; notaulus and parapsidal sutures impressed; dorsal face and declivity of propodeum meeting by means of lateral tubercles confining a shallow median depression; postpetiole with laterally produced spiracles and ventral face with rugosi­ ties at its posterior end.

Pilosity: Only long hairs (same as workers) more profuse than in conspecific workers.

Type Material

Type Loc.: Utiariti, Rio Papagaio, MT, Brasil (13° 02'S, 58° 17'W). Holotype and 20 paratypes; Faz. Junqueira Vilela, munic. Diamantino, MT, Brasil (14° 25'S, 56° 26'W), 10 paratypes; Sinop, MT, Brasil (12" 31'S. 55" 37'W), 3 paratypes; Vilhena, RO, Brasil ( 12° 43'S. 60° 07'W), 29 paratypes.

Holotype (worker) and 11 paratypes (1 queen, 10 workers) from Utiariti, 3 paratypes (worker) from Sinop, 6 ( 1 queen, 5 workers) from Junqueira Vilela and 10 (2 queens, 8 workers) from Vilhena at Museu de Zoologia da USP: 4 paratypes (workers) from Utiariti, 2 (workers) from Junqueira Vilela and 2 (workers) from Vilhena at British Museum of Natural History; 5 paratypes (workers) from Utiariti, 2 (workers) from Junqueira Vilela and 3 (workers) from Vilhena at Museum of Comparative Zoology; 14 paratypes (2 queens, 12 workers) from Vilhena at Instituto Nacional de Pesquisas da Amazonia, Manaus.

Kempf already noticed that the specimens collected in Utiariti might belong to a new species. Accordingly he labelled them as: “Megalomyrmex pr. goeldii, talvez n. sp., W.W. Kempf det.”


The name ayri means small in Tupi, referring to the workers of this species, relatively smaller than Megalomyrmex goeldii workers.


References based on Global Ant Biodiversity Informatics

  • Dias N. D. S., R. Zanetti, M. S. Santos, M. F. Gomes, V. Peñaflor, S. M. F. Broglio, and J. H. C. Delabie. 2012. The impact of coffee and pasture agriculture on predatory and omnivorous leaf-litter ants. Journal of Insect Science 13:29. Available online:
  • Dias N. S., R. Zanetti, M. S. Santos, J. Louzada, and J. H. C. Delabie. 2008. Interaction between forest fragments and adjacent coffee and pasture agroecosystems: responses of the ant communities (Hymenoptera, Formicidae). Iheringia, Sér. Zool., Porto Alegre, 98(1): 136-142.
  • Santos M. S., J. N. C. Louzada, N. Dias, R. Zanetti, J. H. C. Delabie, and I. C. Nascimento. 2006. Litter ants richness (Hymenoptera, Formicidae) in remnants of a semi-deciduous forest in the Atlantic rain forest, Alto do Rio Grande region, Minas Gerais, Brazil. Iheringia, Sér. Zool., Porto Alegre, 96(1): 95-101.
  • 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.
  • da Silva de Oliveira A. B., and F. A. Schmidt. 2019. Ant assemblages of Brazil nut trees Bertholletia excelsa in forest and pasture habitats in the Southwestern Brazilian Amazon. Biodiversity and Conservation 28(2): 329-344.