Megalomyrmex leoninus

Dr. Klaus Jaffe kindly forwarded me a colony of M. leoninus collected by him at Cucuta, Merida, Venezuela among stones. He did not notice any definite entrances, galleries or chambers. The colony contained 450 workers and 35 males, but no immatures, nor queens. (Brandão 1990)

Identification
Brandão (1990) - M. leoninus is the type species of the genus by monotypy. It's original description includes some highly variable characters as color, size and pilosity. M. leoninus presents the widest range of variation on the morphometric measurements taken. This variation is followed by an extreme variation in color pattern, from a bright red to a deep brown, almost black.

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil, Colombia, Ecuador, French Guiana, Guyana, Suriname, Trinidad and Tobago, Venezuela.

Nomenclature

 * . Megalomyrmex leoninus Forel, 1885a: 372 (w.) COLOMBIA.
 * Type-material: lectotype worker (by designation of Brandão, 1990b: 436), 2 paralectotype workers.
 * Type-locality: lectotype Colombia: (no further data) (Landolt); paralectotypes with same data.
 * Type-depositories: MHNG (lectotype); MHNG, MZSP (paralectotypes).
 * Status as species: Emery, 1890a: 65; Emery, 1890b: 47 (footnote, in key); Dalla Torre, 1893: 71; Forel, 1901h: 61; Forel, 1905b: 159; Wheeler, W.M. 1909b: 237 (in key); Emery, 1922e: 190; Wheeler, W.M. 1925a: 34 (in key); Ettershank, 1966: 105; Kempf, 1972a: 140; Brandão, 1990b: 436 (redescription); Brandão, 1991: 355; Bolton, 1995b: 249; Brandão, 2003: 153; Fernández & Serna, 2019: 806.
 * Distribution: Brazil, Colombia, Suriname, Trinidad, Venezuela.

Worker
Brandão (1990) - Mandibles smooth: anterior clypeal border round with median denticle: 3-segmented antennal club: frontal suture impressed; 22 ocular facets at compound eye largest diameter; occipital margin raised but not visible in head full face view; promesonotal suture impressed; mesosternum and metasternum without acrotergites; declivity smooth: epipetiolar carina complete; nonpedunculate petiole with anteroventral tooth but no flange; dorsal margin of petiolar node, in side view. concave; dorsal margin of petiole, in frontal view, round; postpetiole ventral face without process; apex of femura acuminate.

Color: reddish-brown (gaster may be darker than rest of the body).

Type Material
Colombia. Lectotype designation: Lectotype and paralectotype at Museum de la Ville de Geneve. Paralectotype at Museu de Zoologia da USP.

References based on Global Ant Biodiversity Informatics

 * Brandao, C.R.F. 1991. Adendos ao catalogo abreviado das formigas da regiao neotropical (Hymenoptera: Formicidae). Rev. Bras. Entomol. 35: 319-412.
 * 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
 * Emery C. 1890. Voyage de M. E. Simon au Venezuela (Décembre 1887 - Avril 1888). Formicides. Annales de la Société Entomologique de France (6)10: 55-76.
 * Fernandes I., and J. de Souza. 2018. Dataset of long-term monitoring of ground-dwelling ants (Hymenoptera: Formicidae) in the influence areas of a hydroelectric power plant on the Madeira River in the Amazon Basin. Biodiversity Data Journal 6: e24375.
 * Fernández, F. and S. Sendoya. 2004. Lista de las hormigas neotropicales. Biota Colombiana Volume 5, Number 1.
 * Forel A. 1901. Formiciden des Naturhistorischen Museums zu Hamburg. Neue Calyptomyrmex-, Dacryon-, Podomyrma- und Echinopla-Arten. Mitt. Naturhist. Mus. Hambg. 18: 43-82.
 * Forel A. 1905. Miscellanea myrmécologiques II (1905). Ann. Soc. Entomol. Belg. 49: 155-185.
 * Franco W., N. Ladino, J. H. C. Delabie, A. Dejean, J. Orivel, M. Fichaux, S. Groc, M. Leponce, and R. M. Feitosa. 2019. First checklist of the ants (Hymenoptera: Formicidae) of French Guiana. Zootaxa 4674(5): 509-543.
 * Leponce M., J. H. C. Delabie, J. Orivel, J. Jacquemin, M. Calvo Martin, and A. Dejean. 2019. Tree-dwelling ant survey (Hymenoptera, Formicidae) in Mitaraka, French Guiana, in Touroult J. (ed.), “Our Planet Reviewed” 2015 large-scale biotic survey in Mitaraka, French Guiana. Zoosystema 41 (10): 163-179.
 * Salinas P. J. 2010. Catalogue of the ants of the Táchira State, Venezuela, with notes on their biodiversity, biogeography and ecology (Hymenoptera: Formicidae: Amblyioponinae, Ponerinae, Proceratiinae, Myrmicinae, Ecitoninae, Formicinae, Pseudomyrmecinae, Dolichoderinae). Boletín de la SEA 47: 315-328.