Neivamyrmex swainsonii (Shuckard)

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 : 489-490

Neivamyrmex swainsonii (Shuckard)

Figures 15, 25, 30, 46, 73, 122, 136, 147, 149

Labidus swainsonii Shuckard , 1840: 201 (m). BRAZIL ( BMNH). Westwood, 1842: 76. F. Smith, 1859: 8 (m).

Labidus mexicanus F. Smith , 1859: 7 (m). MEXICO, Orizaba ( BMNH) (examined). NEW SYNONYMY .

Eciton (Acamatus) nitens : Pergande, 1895: 874. Misidentification

Eciton (Acamatus) swainsonii : Emery, 1900: 515, 525. Emery, 1910: 27. Santschi, 1916: 370. Santschi, 1931: 74. Gallardo, 1920: 379. Borgmeier, 1923: 50.

Eciton (Acamatus) arizonense Wheeler , 1908 c: 414 (m). U. S. A., Arizona, Nogales. (MCZC). Emery 1910: 25. M. R. Smith, 1942: 581 (m)

Eciton (Acamatus) lieselaei : Gallardo, 1920: fig. 32. Misidentification

Eciton (Neivamyrmex) swainsoni : Borgmeier, 1948 b: 462.

Eciton (Neivamyrmex) arizonense : Creighton, 1950: 69 - 70 (m).

Neivamyrmex swainsoni : Borgmeier, 1953: 16. Borgmeier, 1955: 454 - 458 (m). Watkins, 1972: 352 (m). Watkins, 1976: 24 (m). Cokendolpher & Francke, 1990: 13.

Eciton (Neivamyrmex) commutatum : M. R. Smith, 1942: 568 (misidentification).

Neivamyrmex swainsoni arizonensis : Borgmeier, 1953: 19 (m).

Neivamyrmex fallax Borgmeier , 1953: 48 (w). U. S. A., Texas, Victoria ( USNM). NEW SYNONYMY

DISTRIBUTION (Map 11)

UNITED STATES: Kansas, Louisiana and Texas, west to California; MEXICO: border states south to Chiapas and Yucatan; south to ARGENTINA.

SPECIMENS EXAMINED

We have 123 records for this species in the United States.

DISCUSSION

F. Smith's Labidus mexicanus was made a variety of pilosus by Borgmeier (1936), a synonym of pilosus by M. R. Smith (1942) and, finally, a subspecies of pilosus by Borgmeier (1953), where it has remained. We have examined the type of L. mexicanus and determined that none of the above decisions was correct. Labidus mexicanus F. Smith is, instead, a junior synonym of N. swainsonii (New synonymy).

Due to its large size and relative abundance N. swainsonii is easily one of North America ’ s most conspicuous army ants. Surprisingly, for many years the worker form of this common and wideranging species was unknown. We have determined that N. fallax is the worker of N. swainsonii . The evidence for this association is scanty: it is based on a worker of N. fallax found attached to the leg of a male collected in Arizona. Although throughout the United States and Mexico the ranges of these two taxa overlap nicely, N. fallax is unknown south of Guatemala.

Differences do exist between the North and South American populations; however after having examining the type specimen from Brazil and several other specimens from Central and South America we are forced to conclude that we are dealing with a single wide ranging and slightly variable species.

Automontage images of the male caste may be viewed at antweb. org