Nothing is known about the biology of Megalomyrmex pusillus.
Brandão (1990) - Forel (1912) observed a wide deep brown transversal band at the first gaster segment, contrasting with the light-yellow body. This condition is not constant for most samples, but it is present in the three available dealated females. I noticed intraspecific variation among workers in terms of color, presence of median seta at the clypeal set, degree of development of the anteromedian clypeal denticle and propodeum shape. The sample from Alto da Serra, SP, Brasil (types and non-types) have extreme values for all measured characters, as already noticed by Borgmeier (1939).
Distribution based on Regional Taxon Lists
Distribution based on AntMaps
Distribution based on AntWeb specimens
Check data from AntWeb
Brandão (2003) - Of this rather rarely collected, although very distinctive species, I received from Laboratório de Mirmecologia CEPEC / CPDC a worker collected in Poços de Caldas, Minas Gerais state, Brazil (21°48’S, 46°34’W), in October 28, 1991, by A.M.D. Aguiar. This is the first record of this species in Minas Gerais.
Known only from the worker caste.
The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.
- pusillus. Megalomyrmex pusillus Forel, 1912g: 15 (w.) BRAZIL. Brandão, 1990: 453 (q.).
Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.
Brandão (1990) - Smooth mandibles with dental formula (1-2) + 4; anterior border of clypeus in general round with median denticle; frontal suture not impressed; occipital margin not raised: promesonotal suture when present faintly impressed at dorsum; dorsal face and declivity of propodeum meeting in lateral acute tubercles divergent at apex and laterally compressed: declivity smooth; epipetiolar carina not complete dorsally; ventral face of postpetiole with anterior denticle; postpetiole ventral face without process.
Pilosity: long erect or suberect hairs (exceeding compound eyes diameter) at body dorsum and smaller subdecumbert hairs at clypeus, antennae and legs.
Color: bright light yellow.
Brandão (1990) - Differs from conspecific workers in the following characters: triangular head in frontal view with areas of striation at the antenna! sockets and distal portion of lateral area of clypeus. Ocelli equally developed. Median propodeal depression deeper than in workers. Postpetiolar node distinctly broader than petiolar node.
Brandão (1990) - Alto da Serra, SP, Brasil (23°47'S, 46°19'W). Lectotype designation: Lectotype and 1 paralectotype at the Museum de la Ville de Geneve; 1 paralectotype at Naturhistorisches Museum. Basel.
- Brandão, C. R. F. 1990b. Systematic revision of the Neotropical ant genus Megalomyrmex Forel (Hymenoptera: Formicidae: Myrmicinae), with the description of thirteen new species. Arq. Zool. (São Paulo) 31: 411-481 (page 453, queen described)
- Brandão, C. R. F. 2003. Further revisionary studies on the ant gentus Megalomyrmex Forel (Hymenoptera: Formicidae). Pap. Avulsos Zool. (São Paulo) 43: 145-159 PDF
- Forel, A. 1912h. Formicides néotropiques. Part IV. 3me sous-famille Myrmicinae Lep. (suite). Mém. Soc. Entomol. Belg. 20: 1-32 (page 15, worker described)