Neivamyrmex opacithorax (Emery),

Snelling, G. C. & Snelling, R. R., 2007, New synonymy, new species, new keys to Neivamyrmex army ants of the United States., Advances in ant systematics (Hymenoptera: Formicidae): Homage to E. O. Wilson - 50 years of contributions. (Memoirs of the American Entomological Institute 80), pp. 459-550: 486-487

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Neivamyrmex opacithorax (Emery)


Neivamyrmex opacithorax (Emery)  HNS 

Figures 108, 109, 120, 134, 145

Eciton (Acamatus) californicum subsp. opacithorax Emery  HNS  , 1894: 184 (w, in key). U. S. A., Missouri, Doniphan ( MHNG). Emery, 1895 b: 259. Pergande, 1895: 874. Forel, 1899: 28  .

Eciton (Acamatus) opacithorax  HNS  : Emery, 1900 a: 524; Emery, 1910: 25. Wheeler & Long, 1901: 163, 173 (w, q). Wheeler, 1908 b: 411 (m). M. R. Smith, 1924: 84. Mallis, 1941: 62.

Eciton (Acamatus) carolinense  HNS  : Wheeler, 1921: 314 (q). Misidentification

Eciton (Neivamyrmex) opacithorax  HNS  : M. R. Smith, 1932: 555 (w, q, m). M. R. Smith, 1951 [in Muesebeck, et al.]: 781. Buren, 1944: 180. Creighton, 1950: 74.

Eciton (Acamatus) opacithorax var. castaneum Borgmeier  HNS  , 1939 a: 416 (w). COSTA RICA, San Jose ( MCSN)  .

Eciton (Acamatus) californicum  HNS  : Mallis, 1941: 62 (w). Misidentification

Eciton (Neivamyrmex) californicum  HNS  : M. R. Smith, 1942: 560 (w). Misidentification

Eciton (Neivamyrmex) opacithorax subsp. castaneum  HNS  : Borgmeier, 1948: 191 (w, q m). COSTA RICA, San Jose.

Neivamyrmex opacithorax  HNS  : Borgmeier, 1953: 6. Watkins, 1972: 349; Watkins, 1976: 16, 22. Watkins, 1985: 482, 484.


UNITED STATES: Virginia and Tennessee, south to Florida, west to California; MEXICO (Baja California, Jalisco); GUATEMALA; COSTA RICA. SPECIMENS EXAMINED

We have 51 records from within the United States.


Although N. opacithorax  HNS  is a widespread species it is not as commonly encountered as other members of the N. nigrescens  HNS  group. Within the group it is readily recognized by the distinctively shaped mandible and the shiny head. It is presumably a raider on other ant species. Workers of this species were discovered during the processing of a number twig cuttings which contained a colony of Pseudomyrmex championi (Forel)  HNS  in Guatemala. It is unknown if the Neivamyrmex  HNS  were actively entering the colony while it was intact or if the raiding began as the twigs were cut and collected for processing (P. S. Ward, pers. comm.).

Automontage images of N. opacithorax  HNS  may be viewed at antweb. org.


Switzerland, Geneva, Museum d'Histoire Naturelle


Switzerland, Geneva, Museum d'Histoire Naturelle


Italy, Genova, Museo Civico di Storia Naturale


Italy, Genova, Museo Civico di Storia Naturale