Neivamyrmex mandibularis (M. R. Smith)

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 : 477-478

Neivamyrmex mandibularis (M. R. Smith) NEW STATUS

Figures 100, 101,127

Eciton (Neivamyrmex) pilosus subsp. mandibulare M. R. Smith , 1942: 548 (m). U. S. A., Arizona, 30 mi E Quijotoa, Pima Co. ( USNM) examined. Creighton, 1950: 68, 76 .

Neivamyrmex pilosus subsp. mandibularis : Borgmeier, 1955: 375 (m).

DISTRIBUTION (Map 3)

UNITED STATES: Arizona and New Mexico; MEXICO: border states south to Chiapas and Colima.

SPECIMENS EXAMINED

UNITED STATES, ARIZONA, Pima Co.: Santa Rita Mts. , 4000 ft. ( USNM) ; Forestry Cabin, Brown Canyon, Baboquivari Mts. , 3500 ft. ( LACM) ; Baboquivari Mts. ( LACM) . Santa Cruz Co.: Pena Blanca ( LACM) ; Madera Canyon, Santa Rita Mts. ( CASC) . NEW MEXICO, Catron Co.: Whitewater Creek , 5 mi NE Glenwood ( SEMC). Grant Co.: 100 km NW Silver City ( WPMC).

MEXICO, CHIAPAS, Tuxtla Gutierrez , 1000 ft. ( CUIC) . DURANGO, Nombre de Dios ( UCBC) . JALISCO, Chamela , 3000 ft. ( USNM) . OAXACA, 1 mi SE Tamazulapam , 6200 ft . ( UCBC) . SINALOA, Mazatlan ( USNM) ; 5 mi N Mazatlan ( UCBC) . VERA CRUZ, Fortin de las Flores , 3000 ft. ( CUIC) ; 8 mi S Elota ( UCDC) .

DISCUSSION

When M. R. Smith (1942) described this species as a subspecies of N. pilosus he did so primarily on similarities in the shape of the mandible. This difference is consistent throughout the range of this species, a range that lies almost entirely within the much more extensive range of N. pilosus . Were this the only difference between the two, there is no doubt that they would be regarded as conspecific. However, there is a difference, too, in the shape of the paramere. Although quite variable in shape, the paramere of N. pilosus (Figs. 128) is narrowly rounded at the apex; in N. mandibularis the paramere is blunt and broadly rounded. Additionally, the hairs of the compound eyes in N. mandibularis are generally longer and more flexuous than they are in most populations of N. pilosus , but in areas where both forms are present, they are more consistent in this difference.

Workers of N. pilosus are relatively large and are conspicuous when that species is present. No workers of N. pilosus have been found in southern Arizona, even though this is one of the most heavily collected areas for ants in the United States. While absence of proof is not proof of absence, we have allowed this consideration to influence our thinking. Additionally, workers of another species, N. melanocephalus , are available as a possible match for N. mandibularis . At present, we are reluctant to do more than suggest this match-up since recently examined material of N. graciellae (Mann, 1926) , has raised the possibility that this might be the worker of N. mandibularis . That species was originally described from Ototonilco, Jalisco, Mexico, well within the range of N. mandibularis , and this species is another member of the N. pilosus group. For the present, then, we leave the question unresolved. But, in any case, we have concluded that N. mandibularis is best regarded as a species apart from N. pilosus .