Neivamyrmex melanocephalus

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Neivamyrmex melanocephalus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dorylinae
Genus: Neivamyrmex
Species: N. melanocephalus
Binomial name
Neivamyrmex melanocephalus
(Emery, 1895)

Neivamyrmex melanocephalus casent0103136 profile 1.jpg

Neivamyrmex melanocephalus casent0103136 dorsal 1.jpg

Specimen labels


Snelling and Snelling (2007) - This rather large distinctive species is only rarely encountered in the United States and its principal range lies in Mexico and Guatemala. One foraging raid of N. melanocephalus was observed. It occurred in full daylight and the workers were taking a variety of small arthropods (B. V. Brown, pers. comm). We believe that Neivamyrmex mandibularis is the likely male of N. melanocephalus, but it is also possible that N. mandibularis could be the opposite sex of Neivamyrmex graciellae.


Smith (1942) - The major worker of melanocephalum can be readily distinguished by the form of the mandibles; size and shape of the scape; conspicuous eyes; rounded posterior comers of the head; the contrast in color and sculpture of head and gaster as compared with thorax; sculpture of pronotum; and the form of the petiole and postpetiole.

The color of the thorax varies considerably, ranging from light yellowish brown through deeper reddish brown to almost blackish; the color seems more variable in smaller workers than in the larger workers. The sculpture of the thorax also varies greatly, being much more rough in some individuals than in others. The head of the smaller worker is uniformly longer and narrower than the head of the major worker.

The major worker is most likely to be confused with that of pilosum. It may be distinguished, however, by the different color and sculpture of the thorax; the more weakly arched pronotum; and the weakly developed tooth on the petiolar peduncle; which is never so large or acute, or directed so far posteriorly, as that of pilosum.

Keys including this Species


United States: Arizona; Mexico: south at least to Oaxaca and Morelos.

Distribution based on Regional Taxon Lists

Nearctic Region: United States.
Neotropical Region: Guatemala, Mexico (type locality).

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb



Known only from the worker caste.



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

  • melanocephalus. Eciton melanocephalum Emery, 1895c: 260 (footnote) (w.) MEXICO (Nayarit).
    • Type-material: syntype workers (number not stated).
    • Type-locality: Mexico: Nayarit, Tepic (T. Pergande).
    • Type-depositories: MCZC, MHNG, MSNG, USNM.
    • Combination in E. (Acamatus): Emery, 1910b: 24;
    • combination in E. (Neivamyrmex): Smith, M.R. 1942c: 549;
    • combination in Neivamyrmex: Borgmeier, 1953: 6.
    • Status as species: Pergande, 1896: 874; Forel, 1899c: 28; Emery, 1910b: 24; Wheeler, W.M. 1914b: 41; Smith, M.R. 1942c: 549 (redescription); Creighton, 1950a: 72; Smith, M.R. 1951a: 780; Borgmeier, 1953: 19; Borgmeier, 1955: 385 (redescription); Smith, M.R. 1958c: 109; Smith, M.R. 1967: 345; Watkins, 1971: 94 (in key); Kempf, 1972a: 156; Watkins, 1972: 348 (in key); Hunt & Snelling, 1975: 21; Watkins, 1976: 16 (in key); Smith, D.R. 1979: 1331; Watkins, 1982: 210 (in key); Watkins, 1985: 481 (in key); Bolton, 1995b: 290; Mackay & Mackay, 2002: 59; Snelling, G.C. & Snelling, 2007: 479; Branstetter & Sáenz, 2012: 254.
    • Senior synonym of xipe: Smith, M.R. 1942c: 549; Creighton, 1950a: 72; Smith, M.R. 1951a: 780; Borgmeier, 1953: 19; Borgmeier, 1955: 385; Kempf, 1972a: 156; Smith, D.R. 1979: 1331; Bolton, 1995b: 290; Snelling, G.C. & Snelling, 2007: 479.
    • Distribution: Guatemala, Honduras, Mexico, U.S.A.
  • xipe. Eciton (Acamatus) melanocephalum subsp. xipe Wheeler, W.M. 1914b: 41 (w.) MEXICO (Hidalgo).
    • Type-material: syntype workers (number not stated, “numerous”).
    • Type-locality: Mexico: Hidalgo, San Miguel, ca 7000 ft, 1913 (W.M. Mann).
    • Type-depositories: MCZC, MHNG, NHMB.
    • Junior synonym of melanocephalus: Smith, M.R. 1942c: 549; Creighton, 1950a: 72; Smith, M.R. 1951a: 780; Borgmeier, 1953: 19; Borgmeier, 1955: 385; Kempf, 1972a: 156; Smith, D.R. 1979: 1331; Bolton, 1995b: 292; Snelling, G.C. & Snelling, 2007: 479.

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



Smith (1942) - Major. Length 4.5-5.5 mm.

Head approximately as broad as long; broadest anteriorly; with convex sides and very weakly emarginate posterior border. Eye ocelluslike, very distinct against black background of head. Mandible rather large, subtriangular, with well-defined superior, inferior, and masticatory borders; superior border without any distinct excision or protuberance. Antennal scape large, curved; exceeding posterior border of eye by at least its greatest width; all segments of funiculus distinctly longer than broad. Promesonotum, in profile, very feebly arched; meso-espinotal constriction weakly developed. Thorax without dorsal sutures. Pronotum with very small but distinct transverse carina. Petiole longer than broad, with somewhat abrupt posterior surface and a more gently sloping anterior surface; anterior surface constricted before its termination at the thorax. Legs rather long. Petiolar peduncle with very small anteroventral tooth, which is directed more ventrad than posteriorly. Postpetiole broader than petiole, subtrapezoidal, broader posteriorly than anteriorly, with convex sides and straight anterior end.

Head, dorsal surface of petiole and postpetiole, and gaster smooth and shining; mandibles, funiculi, thorax, and tarsi subopaque or opaque. Mandibles longitudinally striated, with scattered piligerous punctures. Head highly polished, bearing very small, scattered, piligerous punctures. Thorax covered with dense, granular punctures, which are interspersed with foveolae; meso- and metapleura more coarsely sculptured, the sculpturing of a rugose-reticulate nature; pronotum longitudinally rugulose.

Body with numerous suberect to erect, yellowish hairs of unequal length, some of which are unusually long.

Head and gaster almost black. Mandibles, anterior border of head, thorax, legs, petiole, and postpetiole of a much lighter reddish brown.

Type Material

Smith (1942) - Tepic, Mexico. Cotypes in the United States National Museum.


  • Alatorre-Bracamontes, C.E., Vásquez-Bolaños, M. 2010. Lista comentada de las hormigas (Hymenoptera: Formicidae) del norte de México. Dugesiana 17(1): 9-36.
  • Borgmeier, T. 1953. Vorarbeiten zu einer Revision der neotropischen Wanderameisen. Stud. Entomol. 2: 1-51 (page 6, Combination in Neivamyrmex; page 19, Senior synonym of xipe)
  • Borgmeier, T. 1955. Die Wanderameisen der neotropischen Region. Stud. Entomol. 3: 1-720 (page 385, see also)
  • Emery, C. 1895d. Beiträge zur Kenntniss der nordamerikanischen Ameisenfauna. (Schluss). Zool. Jahrb. Abt. Syst. Geogr. Biol. Tiere 8: 257-360 (page 260, (footnote) worker described)
  • Snelling, G. C.; Snelling, R. R. 2007. New synonymy, new species, new keys to Neivamyrmex army ants of the United States. In Snelling, R. R., B. L. Fisher, and P. S. Ward (eds). Advances in ant systematics (Hymenoptera: Formicidae): homage to E. O. Wilson - 50 years of contributions. Memoirs of the American Entomological Institute 80:459-550. PDF
  • Smith, M. R. 1942c. The legionary ants of the United States belonging to Eciton subgenus Neivamyrmex Borgmeier. Am. Midl. Nat. 27: 537-590 (page 549, Combination in E. (Neivamyrmex), Senior synonym of xipe)

References based on Global Ant Biodiversity Informatics

  • Alatorre-Bracamontes, C.E. and M Vasquez-Bolanos. 2010. Lista comentada de las hormigas (Hymenoptera: Formicidae) del norte de México. Dugesiana 17(1):9-36
  • Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology
  • Esteves F. A., C. R. F. Brandao, and L. P. Prado. 2011. The type specimens of Dorylomorph ants (Hymenoptera, Formicidae: Aenictinae, Ecitoninae, Cerapachyinae, Leptanilloidinae) deposited in the Museu de Zoologia da Universidade de Sao Paulo, Brazil. Papeis Avulsos de Zoologia 51(22): 341-397.
  • Fernandes, P.R. XXXX. Los hormigas del suelo en Mexico: Diversidad, distribucion e importancia (Hymenoptera: Formicidae).
  • Hernandez, F. Varela and G. Castano-Meneses. 2010. Checklist, Biological Notes and Distribution of Ants (Hymenoptera: Formicidae) from Barranca de Metztitlán Biosphere Reserve, Hidalgo, Mexico. Sociobiology 56(2):397-434
  • Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
  • Pergande, T. 1895. Mexican Formicidae. Proceedings of the California Academy of Sciences Ser. 2 :850-896
  • Quiroz-Robledo, L.N. and J. Valenzuela-Gonzalez. 2006. Las hormigas Ecitoninae (Hymenoptera: Formicidae) de Morelos, México. Revista Biologia Tropical 54(2):531-552
  • Snelling G. C. and R. R. Snelling. 2007. New synonymy, new species, new keys to Neivamyrmex army ants of the United States. Memoirs of the American Entomological Institute 80: 459-550
  • Varela-Hernandez, F., M. Rocha-Ortega, W. P. Mackay, and R. W. Jones. 2016. Lista preliminar de las hormigas (Hymenoptera: Formicidae) del estado de Queretaro, Mexico. Pages 429-435 in . W. Jones., and V. Serrano-Cardenas, editors. Historia Natural de Queretaro. Universidad Autonoma de Queretaro, Mexico.
  • Vasquez-Bolanos M. 2011. Checklist of the ants (Hymenoptera: Formicidae) from Mexico. Dugesiana 18(1): 95-133.
  • Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133
  • Watkins II, J.F. 1982.The army ants of Mexico (Hymenoptera: Formicidae: Ecitoninae). Journal of the Kansas Entomological Society 55(2): 197-247.
  • Watkins J. F., II 1976. The identification and distribution of New World army ants (Dorylinae: Formicidae). Waco, Texas: Baylor University Press, 102 pp