Neivamyrmex moseri

This species apparently is subterranean, as it lacks eyes and was collected in a subterranean bait. No specimens were collected in surface baits or in pitfall traps. It was collected in a highly disturbed area in a grassland mixed with a few small trees (Acacia sp., Prosopis sp.). The area is flat with loam soils. Neivamyrmex harrisii and Neivamyrmex swainsonii, in addition to several other ant species, occur in the area. Labidus coecus and Solenopsis geminata were also collected in subterranean traps. The area was moderately infested with the red imported fire ant, Solenopsis invicta. (Mackay 1988, as reported for the synonomized N. isodentatus)

Identification
Key to the Neivamyrmex species of the United States

Neivamyrmex moseri is easily separated from all other described United States species by its unique mandibular structure: there are three large teeth that are usually approximately equal in size; much smaller intercalary denticles may be present. We should note further that the statement by Watkins (1969) that N. moseri workers lack a subantennal lamella is only partly correct; the lateral extension of the frontal carina that runs below the socket is present, but is not elevated to form a distinct lamella in most specimens examined. A low lamella is present in a few specimens. (Snelling and Snelling 2007)

Distribution based on Regional Taxon Lists
Nearctic Region: United States. Neotropical Region: Honduras.

Nomenclature

 *  moseri. Neivamyrmex moseri Watkins, 1969: 529, figs. 1-5 (w.) U.S.A. Watkins, 1971: 96 (q.). Senior synonym of isodentatus: Snelling, G.C. & Snelling, R.R., 2007: 483.
 * isodentatus. Neivamyrmex isodentatus Mackay, 1998a: 333, fig. 1 (w.) U.S.A. Junior synonym of moseri: Snelling, G.C. & Snelling, R.R., 2007: 482.

Worker
Major Length 3.10 mm. Head: median length without mandibles 0.78 mm, width 0.83 mm, sides slightly convex, posterior margin broadly concave with rounded corners. Eyes absent. Mandibles characteristic, but somewhat similar to those of N. macrodentatus. Basal tooth large, triangular, not curved. Masticatory border with three teeth, the middle tooth less than half the length of the outer teeth, posterior tooth longes.t. Frontal carina short, curved outward and upward to form distinct lamella ending at the lower, inner edge of the antennal depression. Antenna short (1.10 mm); scape length (0.375 mm), about one-half median head length, greatest width 0.125 mm, narrower at the base and gradually thickening distally; flagellum length 0.725 mm, greatest width 0.10 mm, gradually thickening distally, last segment more than two times length of penultimate segment. Alitrunk robust, dorsally flattened, length 1.10 mm, greatest width 0.50 mm. Mesoepinotal suture well defined. Epinotum slightly longer than wide, length 0.45 mm, width at base 0.38 mm, posterior surface in profile steeply sloped and moderately concave (slightly concave to almost straight in some specimens). Petiole in profile strongly convex dorsally; anteroventral tooth large, pellucid, keel-shaped. Petiole from above slightly longer than broad, length 0.35 mm; greatest width 0.30 mm, length of node 0.25 mm, with slightly convex sides and concave anterior face. Postpetiole wider than long with convex sides, length 0.25 mm, greatest width 0.35 mm. Gaster somewhat flattened and elongated (more elongated in smaller specimens), length 1.10 mm, greatest width 0.80 mm. Hind femur and tibia about same length (0.65 mm). Proximal segment of hind tarsus almost as long (0.43 mm) as remaining segments combined (0.48 mm). Scattered punctures on the head, alitrunk, petiole and postpetiole, but most distinct on the dorsum of the alitrunk, petiole and postpetiole. Mesopleura shagreened. Body, including appendages, shining, yellowish brown, covered with scattered erect and suberect hairs which are longest on the gaster.

Minor Length 1.90 mm. Head slightly longer than wide, median length without mandibles 0.48 mm, greatest width 0.40 mm, sides almost parallel, posterior margin broadly concave with rounded corners. Median carina short, narrow, resembling an inverted "Y" with short outwardly curved "arms." Flagellum (0.43 mm) approximately two times length of scape (0.23 mm), last segment two times length of penultimate segment. Mandible somewhat similar to that of N. macrodentatus minor, length 0.25 mm; "basal tooth" forms outermost tooth of masticatory margin and is similar in size and shape to the next two adjacent teeth, posterior tooth large, more than three times length of other teeth. Dorsum of alitrunk unusually flattened, sides almost perpendicular, length 0.70 mm, greatest width 0.25 mm, mesoepinotal suture well defined. Petiole approximately as long as wide (0.15 mm), slightly convex sides, strongly convex dorsally, anteroventral tooth small, but distinct. Postpetiole wider (0.18 mm) than long (0.10 mm). Gaster elongate (0.70 mm), somewhat flattened, greatest width 0.43 mm, greatest height 0.33 mm. Hind femur (0.35 mm) slightly longer than tibia (0.33 mm). Length of proximal segment of hind tarsus (0.20 mm) two-thirds total length of remaining segments (0.30 mm). Body, including appendages, covered with scattered, moderately long, suberect hairs; surface smooth, except shagreened mesopleura; shining, yellowish.

Type Material
Type locality and materials studied. Numerous workers collected by John C. Moser (April 13, 1959) 7 miles W. Alexandria, La. (92° 36' long., 31° 14' lat.) Kisatchie Nat. Forest, Rapides Parish, Louisiana, from a single colony found at a depth of one foot in the excavated surface subsoil of a large nest of Atta texana (Buckley).

Types (red labels). One holotype major and one paratype minor deposited in the Museum of Comparative Zoology, Harvard University, Cambridge, Mass.; other paratypes deposited in the American Museum of Natural History, New York; Borgmeier's collection, Sao Paulo, Brasil (in care of Walter W. Kempf), and the collection of J. F. Watkins, Baylor University, Waco, Texas.