Subfamily MYRMICINAE
Tribe STENAMMINI
Aphaenogaster lamellidens Mayr 1886

Author: Joe A. MacGown
Mississippi Entomological Museum, Mississippi State University, MS 39762
Uploaded 3 November 2008, updated 18 August 2026

Introduction
Ants in the genus Aphaenogaster are medium sized to large, slender with long legs and antennae, usually have propodeal spines (a few species lack spines), have 12 segmented antennae with the last 4 segments forming a weak club. The genus is widespread in North America and species nest in rotting wood, under bark, and in soil.

Diagnosis.Worker: Slender, medium sized (TL ≈ 4.0–7.0 mm); entire body including appendages reddish brown, gaster sometimes lighter, femora often darker, giving the legs a banded appearance; head, mesosoma, and waist with strong punctation and rugoreticulation (especially on face), gaster shiny; entire body with numerous, short, erect, light to brownish setae; appressed pubescence sparse. Head longer than wide; elongate ovate, convex posteriorly, low occipital carina present;  mandibles triangular with apical tooth the longest followed by 3–4 smaller teeth and 4–5 denticles; frontal carina not covering antennal bases, with a tooth-like lobe that points rearward toward the posterior of the head; antennal scape not bent at base; scapes surpassing posterior margin of head about ¼ of its length; antenna with 12 antennomeres; apical four antennomeres forming a loose club, eyes large, located on sides of head at midway point; ocelli absent. Mesosoma not entire, promesonotum strongly arched, raised above metanotum;, with distinct metanotal suture; propodeal flattened dorsally, longer than declivity, declivious face steep (70–80°), propodeal spines elongate, directed posteriorly; legs long, mid and hind tibia with a single simple spur. Waist two-segmented; petiole pedunculate, with raised, rounded triangular node, flattened ventrally; postpetiole with raised, rounded node, flattened ventrally; Sting atrophied.

Queen: Larger than worker (TL ≈ 8.0–8.5 mm); color similar to worker, but sometimes darker; sculpture on head, mesosoma, and waist similar to worker, but stronger; numerous short, yellowish brown, erect setae present on entire body, more numerous and shorter than in worker. Head slightly wider than long, posterior margin slightly convex; mandible similar in shape and dentition to worker except teeth stouter; antennae similar to worker but scape wider, surpassing posterior margin of head by about 1/4 of its length; eyes enlarged, larger than worker; ocelli present. Mesosoma enlarged, rounded rectangular; mesoscutum broadly rounded anteriorly; propodeum gently sloped from mesoscutellum toward spines which are short, triangular and directed posteriorly; declivity steep, similar to worker. Wings when present with light brown tint; forewing with stigma, and with closed costal, basal, subbasal, discal, and two submarginal cells. Waist similar to worker but petiolar peduncle more thickened.

Male: About the size of worker (TL ≈ 6.0 mm), winged, head black, mesosoma dark brown, waist and gaster, legs, and antennae lighter brown; head punctate, propodeum with transverse striae, remainder of body with reduced sculpture; numerous erect, brownish setae present on entire body. Head flattened; mandibles triangular, elongate with 6 to 9 teeth with apical tooth the longest, then teeth successively smaller; eyes extremely large about ½ the length of head, located on lower half of head; three large ocelli present; scape short, subequal to antennomeres II-III; antennae with 13 antennomeres, apical antennomeres slightly enlarged, but  not forming and obvious club. In lateral view thorax enlarged, rounded square, and elevated above propodeum, mesoscutum broadly curved anteriorly and projecting over pronotum. Wings clear, forewing with six closed cells as in queen; propodeum lacking spines but with prominent rounded triangular protuberances; waist segments with both nodes rounded and less raised than in worker and queen; parameres elongate triangular, with numerous elongate curved setae present.

Similar species. Aphaenogaster lamellidens differs from all other species in the region by having a tooth-like lobes on the frontal carina.

Biology and Economic Importance
Habitat: Aphaenogaster lamellidens is a widespread and common species in southeastern forests where it nests in rotting wood. Colonies range from small to extremely large with thousands of workers. Aphaenogaster lamellidens, in my estimation, must be one of the most common ants in forested areas in central to north MS and AL. We have collected this species in oak-hickory forests, in upland hardwood forests, dry to mesic forests, bottomland hardwood forests, mixed pine-hardwood forests, and other woodland habitats. It has also been reported from xeric and mesic hammocks in Florida (Van Pelt 1958) and longleaf pine savannas (Dash 2005). (Similarly, James Trager has found this species in remnant and better-quality second-growth, dry-mesic and mesic woodlands, especially where oaks are present. He notes that throughout its range it is reported that A. lamellidens nests in soil, under rocks, and in or under wood that is in the mid to latter stages of decomposition, especially smaller diameter pieces lying on the ground, but in Missouri it seems to have a preference for nesting in red-rotten wood on the floor of mesic woodlands on acidic soils. In Alabama and Mississippi, we frequently find this species nesting in soil at the bases of trees, under rotting logs, in rotting logs and stumps, under bark, and in standing trees. Although I have found colonies in or at bases of numerous species of oaks, I have found it to be especially common in standing dead or logs of loblolly pine trees (Pinus taeda).

Natural History: Colonies are often large, sometimes with thousands of workers present. Similar to A. fulva, this species is considered to be a generalized predator. Smith (1979) notes that it feeds on dead and live insects.

Flight Period: We have collected alates in late June in Mississippi.

Distribution
Smith (1979) gives the distribution of A. lamellidens as N.Y. s. to Fla., w. to Ill., Mo., and Tex. In the Southeast, this species is known to occur in AL, AR, FL, GA, LA, MO, MS, NC, SC, TN.

Pest Status. Members of this genus have atrophied stingers and thus, are not stinging pests. Although it nests in rotting wood, it has only rarely been reported as a structural pest

Literature Cited
Dash, S. T. 2005. Species Diversity and biogeography of Ants (Hymenoptera: Formicidae) in Louisianan, with Notes on their Ecology. M.S. Thesis, Louisiana State University, 290 pp

Smith, D. R. 1979. In Catalog of Hymenoptera in America north of Mexico. Smithsonian Institution Press, Washington D. C. Vol. 2, pp. 1323-1427.

Van Pelt, A. F. 1958. The ecology of the ants of Welaka Reserve Florida (Hymenoptera: Formicidae)Part II: annotated list. The American Midland Naturalist 59: 1-60.

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