Megalomyrmex wallacei Mann 1916

Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia

worker lateral view

worker face view


Mandibles with 5 distinct teeth, apical tooth largest, proximal tooth considerably smaller, remaining three teeth the smallest and subequal in size; mandibles shining, with large piligerous punctures; occipital carina visible in face view; propodeal suture deeply impressed; propodeum not bituberculate; ventral margin of postpetiole produced as a rounded lobe; color red brown; HW 0.99; HL 1.35, SL 1.55; WL 1.91 (n=1).


Brazil (Amazonas, Rondonia, Pará, Tocantins), Guyana, Colombia, Costa Rica (Brandčo 1990, 2003). Costa Rica: Atlantic and southern Pacific lowlands.

Natural History

This species occurs in mature wet forest. It nests in small cavities in the low arboreal zone, and recruits to baits on the forest floor.

Selected Records

Longino #3733: La Selva. I collected an entire nest. It was inside a 6cm long rotten cacao pod on the trunk of a cacao tree overhanging the trail. 93 workers were inside the pod. There was no definite queen, and there was abundant brood of all sizes, from eggs to pupae. The workers showed considerable size variation, and larger workers had an enlarged mesonotum. I also found a lone Pheidole queen in the pod.

Barger #NNB/PLT/02: La Selva. Recruiting to baits on ground.

Longino 4Dec81/1140: Los Planes, Corcovado National Park. General collection of ants from ground and low vegetation.


Brandčo (2003) identified Costa Rican material as wallacei. He notes that the species exhibits considerable morphological variation. Costa Rican specimens will not key to wallacei in Brandčo's 1990 revision because the mandibles are smooth with large piligerous punctures rather than striate. Also Brandčo's figure of wallacei (1990:456, fig. 7) shows a subquadrate propodeal profile with little impression of the metanotal groove, in striking contrast to the Costa Rican material.

Literature Cited

Brandčo, 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, Sčo Paulo 31:411-481.

Brandčo, C. R. F. 2003. Further revisionary studies on the ant genus Megalomyrmex Forel (Hymenoptera: Formicidae: Myrmicinae: Solenopsidini. Papéis Avulsos de Zoologia 43:145-159.

Page author:

John T. Longino, The Evergreen State College, Olympia WA 98505 USA.

Date of this version: 20 March 2004.
Previous versions of this page: 2 June 1998.
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