Neivamyrmex carolinensis

This species nests in the soil or under stones on rocky hillsides (in NM). Nests are large, up to 50,000 workers. Foragers are rarely seen above the ground, as they are active nocturnally. Flights occur in May and June. Trail pheromones are used in foraging. This is the only species known to be polygynous (multiple queens in a nest). Workers in laboratory nests with gynes present live longer than workers without the gyne. (Mackay and Mackay 2002)

Identification
Key to the Neivamyrmex species of the United States

This species is unusual among our species of Neivamyrmex, in that the presence of a distinct eye facet is variable, present in some individuals, absent in others. Generally, a facet is present in larger individuals, but even this is subject to variation. This feature is shared with its sister species, Neivamyrmex kiowapache. (Snelling and Snelling 2007)

The dorsum of the head of the worker is smooth and glossy, with scattered piligerous (hair bearing) punctures. The mesosoma, petiole, and postpetiole are mostly smooth, and some areas are distinctly glossy. The node of the petiole is nearly square in shape, as seen from above. The eye is cellus-like, with a definite cornea. (Mackay and Mackay 2002)

Distribution
Virginia and North Carolina south to Florida, west to Tennessee and Louisiana. Neivamyrmex carolinensis is a wide ranging eastern species. Long considered to extend into the central and western United States as far as Arizona, it is now known that the populations west of the Mississippi River belong to a hitherto unrecognized sibling species. That species is described below as Neivamyrmex kiowapache. We are unable to confirm the presence of this species in Nebraska and Ohio (M. R. Smith, 1942) nor have we seen any specimens from Louisiana. (Snelling and Snelling 2007)

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

Habitat
Pine Forest.

Nomenclature

 *  carolinensis. Eciton (Acamatus) carolinense Emery, 1894c: 184 (diagnosis in key) (w.) U.S.A. Wheeler, W.M. 1921d: 314 (q.m.). Combination in E. (Neivamyrmex): Smith, M.R. 1942c: 564; in Neivamyrmex: Borgmeier, 1953: 6. See also: Borgmeier, 1955: 507; Smith, D.R. 1979: 1330; Snelling, G.C. & Snelling, R.R., 2007: 468.

Worker
Smith (1942) - Major Length 3-4 mm.

Head scarcely longer than broad, narrowed posteriorly. Posterior corners of head, from above, feebly produced, bluntly angular and not outwardly curved as in wheeleri (=Neivamyrmex harrisii). Eye ocellus like, distinct, but not large. Mandible constricted at base, then abruptly enlarging on its superior border to form an angular tooth, margin between tooth and masticatory border straight or feebly excised; masticatory border oblique, with three or four irregular teeth on its upper half. Scape robust, approximately three and one-third times as long as its greatest width; scarcely surpassing posterior border of eye; funiculus very noticeably incrassate, all segments except first and last clearly broader than long, last segment as long as combined length of two preceding segments. Frontal carina, from above, forming only a very narrow and indistinct flange in front of antennal socket. Pronotum without sharp transverse carina of wheeleri, but often with feeble indication of a carina when examined from proper direction. Promesonotum, in profile, forming a gently convex, continuous arch very slightly higher than base of epinotum; meso-epinotal suture shallow but distinct; base and declivity of epinotum subequal, the two surfaces meeting to form a bluntly rounded angle, closely approaching a right angle. Petiolar node robust, subquadrate, scarcely longer than broad (approximately five-sixths as broad as long). Peduncle with anteroventral tooth. Postpetiole shorter than petiole but broader; broader than long, broadest posteriorly.

Head, propleura, legs, dorsum of postpetiole, and gaster smooth and shining. Punctures on head sparse, scattered, distinct. Mandible with longitudinal striae in addition to coarse, scattered punctures. Thoracic dorsum subopaque, reticulately shagreened, reticulations interspersed with coarse, scattered, foveolate punctures; punctures seen better in some lights than in others. Meso- and metapleura subopaque, with coarse punctures. Petiole sculptured somewhat as thorax but more feebly so.

Hairs light yellowish or grayish, moderately abundant, of variable length, sub erect to erect.

Yellowish brown to reddish brown, with head and thorax darker. Mandible usually darker than body.

Queen
Smith (1942) - Length 9-13 mm.

Head approximately as long as broad, with gently convex sides, well-rounded posterior corners, and very indistinctly or not emarginate posterior border. Eye extremely small, indistinct, represented by a very pale spot. Mandible long, slender, acute at apex. Scape curved, robust, rather short, slightly less than half the length of the head. Region adjacent and also somewhat posterior to frontal area with a strong, transverse, angular protuberance. A longitudinal, median groove extending posteriorly from clypeus, much broadened above the angular protuberance and extending well back on vertex. External surface of clypeus at most weakly concave, middle of anterior border not deeply but distinctly excised. Dorsal surface of head, from above, lacking median impression anterior to the occipital border, and lateral impression on each side anterior to posterior corner as in nigrescens; head thus viewed, although emarginate behind, not having an extended appearance, and the posterior corners broadly and evenly rounded, not produced. Thorax, from above, approximately two and one-fifth times as long as broad; wider in proportion to its length than thorax of Neivamyrmex opacithorax, wheeleri, and Neivamyrmex nigrescens. Metanotum and epinotum subequal in width, distinctly wider than other areas of thorax. Promesonotal suture obsolete, mesometanotal and metaepinotal sutures fairly distinct. Pronotum convex, not perceptibly marginate anteriorly or laterally. Mesonotum lacking median, longitudinal impression. Epinotum wider than long, with rather distinct, median impression. Thorax, in profile, less than two and four-tenths times as long as high, highest and most convex dorsally in region of promesonotal suture, lowest or most depressed in vicinity of meta-epinotal suture. Petiole, in profile, higher than epinotum; with a prominent tooth beneath somewhat similar to that of opacithorax but smaller; distinctly broader than long, very slightly broader anteriorly than posteriorly, with very shallow and narrow median impression.

Body and appendages, except funiculi and tarsi, shining. Thorax with scattered, fairly distinct to distinct punctures; neither head nor thorax with dense granulate shagreening between punctures as in opacithorax and nigrescens.

Hairs on head, thorax, and petiole moderately abundant, short; longer on gula, mandibles, clypeus, scape, and legs.

Light yellowish brown to brown; gaster usually darker than head or thorax.

Male
Smith (1942) - Length 9-9.25 mm.

Head approximately one and eight-tenths times as broad as long; posterior border rounded but almost obscured by large transverse ridge above each antennal socket. Eye small, convex, not strongly protuberant. Ocelli remarkably small, placed on low protuberance, which is only slightly elevated above general surface of head; lateral ocellus far removed from eye, space between them as great as or greater than space between the lateral ocelli. Frontal carinae converging posteriorly, with distinct median groove between them, the groove interrupted above at level of frontal ridge. Scape approximately as long as first 3 funicular segments combined; funiculus subfiliform. Mandible remarkably elongate and slender, at least 5 times as long as broad, apex blunt. Head, from above, well rounded behind eyes, with posterior corners blending into eyes; no occipital flange. A transverse groove behind the ridge above antennal socket. Eye, in profile, small, narrowed above, failing to occupy all of side of head, there being a small area dorsad and ventrad of eye and a much larger area posterodorsad; head behind ocelli convex. Thorax, in profile, approximately one and one-half times as long as high; slightly projecting anteriorly over head. Prothorax with a very distinct transverse impression anteriorly. Mesonotum with anteromedian and parapsidal lines. Epinotal declivity strongly concave. Legs slender. Tarsal claws weakly toothed. Petiole, from above, approximately one and one-half times as broad as long. Gaster slender, compressed. Paramere not characteristic enough to be clearly described.

Mandible with scattered but distinct punctures. Dorsal surface of head for the most part shining. Thorax with numerous coarse punctures, those of posterior part of mesonotum, scutellum, and sides of thorax largest and most distinct. Punctation of gaster coarse and dense enough to dull somewhat its luster and give gaster a rather sub opaque appearance.

Hairs yellowish, dense, appressed; longest on head, appendages, sides and venter of thorax, petiole, and gaster.

Head, thorax, and petiole black; gaster deep reddish brown. Funiculi and tarsi lighter.

Type Material
Smith (1942) - Belmont, Gaston County, N. C., P. J. Schmitt. Cotypes