Neoponera marginata

From Mackay and Mackay (2010): One colony was nesting under a house. Winged sexuals were collected in December (Brasil). Workers are occasionally collected in pitfall traps. This species preys exclusively on the termite Neocapritermes, especially N. opacus (Mill, 1982a; Wajnberg et al., 2004), using a trail pheromone from the pygidial gland (Hölldobler et al., 1996a). Research by Wajnberg et al. (2004) suggests that they have a magnetic sensory organ in the antenna, although Acosta et al. (2001) concluded the ability to orientate to geomagnetic fields may be due to magnetic iron oxides in the head and abdomen.

Identification
From Mackay and Mackay (2010): The worker and female of P. marginata are easily separated from all of the other species of Pachycondyla by the longitudinal fold or carina on the dorsal surface of the mandible, which none of the other species has. Additionally the worker, female and male are mostly smooth and glossy, which is uncommon in Pachycondyla.

The specimens from Trinidad do not have the strong separation of the two surfaces of the mandibles, atypical of this species.

Distribution
TRINIDAD, BRASIL, BOLIVIA, PARAGUAY, ARGENTINA. (Mackay and Mackay 2010)

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil, Ecuador, Paraguay.

Habitat
Pachycondyla marginata is found in secondary lowland rainforest and urban habitats, from 30 to 700 meters elevation. (Mackay and Mackay 2010)

Nomenclature

 *  marginata. Ponera marginata Roger, 1861a: 8 (w.q.m.) BRAZIL. Combination in Pachycondyla: Roger, 1863b: 18; in Euponera (Mesoponera): Emery, 1901a: 47; in Termitopone: Wheeler, W.M. 1936d: 166; in Pachycondyla: Brown, in Bolton, 1995b: 307. See also: Gallardo, 1918b: 67; Mackay & Mackay, 2010: 455.

Worker
From Mackay and Mackay (2010): Workers are dimorphic (Wheeler, 1936). The mandible has approximately 10 teeth or denticles and is peculiar in that the surface is divided longitudinally into an external and internal area by a longitudinal fold or carina. The anterior medial margin of the clypeus is angulate, the eyes are relatively large (maximum diameter 0.4 mm) located about ½ diameter from the anterior edge of the head (side view). The malar carina is absent. The scape extends slightly past the posterior lateral corner of the head, the posterior border is straight. The pronotum is without a carina, although it is slightly swollen in that region. The metanotal suture breaks the sculpture on the dorsum of the mesosoma and the metanotum is moderately developed. The propodeal spiracle is slit shaped. The petiole is thickened when viewed in profile with the anterior and posterior faces being nearly parallel and the dorsal face being broadly rounded. The subpetiolar process consists of a swollen region, not very well differentiated from the remainder of the petiole. The stridulatory file may be absent or present on the second pretergite and the arolia are poorly developed. The metasternal process consists of two inwardly curved slender lobes. Erect hairs are scattered on the mandibles, clypeus, dorsal and ventral surfaces of the head, dorsum of the mesosoma, legs (mostly suberect), dorsum of the petiole and all surfaces of the gaster; appressed pubescence is essentially absent.

Most surfaces are smooth and glossy, a few striae are present on the mesopleuron and the side of the propodeum.

Queen
From Mackay and Mackay (2010): The female is a large (total length 13 mm) shiny black ant with reddish brown appendages. The mandibles have a large sharp apical tooth followed by a series of small denticles. The mandible is divided longitudinally as in the worker with the inner half being strongly concave. The anterior margin of the clypeus is convex, the sides of the head are narrowed anteriorly and the posterior margin is nearly straight. The malar carina is poorly developed and is represented by a depression surrounded on both sides by slightly swollen areas. The eye is moderate sized (maximum diameter 0.75 mm) and is less than one maximum diameter from the anterior edge of the head (side view). The pronotal shoulder is swollen but does not form a distinct margin; the propodeal spiracle is slit-shaped. The petiole is nearly rectangular-shaped with the anterior and posterior faces being nearly parallel, but is noticeably narrowed dorsally.

Erect hairs are present on most surfaces, including the mandibles, clypeus, dorsal and ventral surfaces of the head, dorsum of the mesosoma, dorsum of the petiole and all surfaces of the gaster. The hairs on the tibiae are mostly suberect and the length of most is approximately ½ the diameter of the tibia.

The dorsum of the head and mesosoma are smooth and glossy, the side of the pronotum and mesopleuron are both smooth and glossy, the side of the propodeum has horizontal striae, the petiole and gaster are smooth and glossy.

Male
From Mackay and Mackay (2010): The male is a moderate sized (total length 11 mm) shiny black ant with brown appendages. The mandibles are tiny. The anterior margin of the clypeus is slightly concave and the clypeus is swollen when viewed in profile. The head is narrowed anteriorly and the posterior border is broadly rounded. The eye is large (maximum diameter 0.73 mm). The median ocellus is about one diameter from the lateral ocellus (seen obliquely from above and from the side). The pronotum is broadly rounded at the shoulder; the propodeal spiracle is slit-shaped. The petiole has the general shape of that of the worker and the female, except that it is more narrowed toward the apex. The stridulatory file is present on the second pretergite.

Erect hairs are abundant on most surfaces, including the clypeus, all surfaces of the head, the scape nearly lacks erect and suberect hairs, erect hairs are present on the dorsum of the mesosoma, dorsum of the petiole and all surfaces of the gaster. The hairs on the legs are mostly suberect. Appressed pubescence is sparse, but is present on the pronotum, middle of the scutum, the scutellum and the dorsal face of the propodeum. The appressed hairs on the dorsum of gaster are sparse.

Most surfaces are moderately to strongly shining, especially the head, the mesosoma and the posterior face of the petiole. There is little sculpture, except for the side of the propodeum, which is covered with coarse rugae.

Type Locality Information
Brasil: Minas Gerais: São João d’El-Rey (Mackay and Mackay 2010)

Etymology
The name of this species is from Latin, marginatus, meaning “enclosed with a border”, referring to the peculiar form of the mandible of the worker and female. (Mackay and Mackay 2010)

Additional References

 * Acosta-Avalos, D., D. Esquivel, E. Wajnberg, H. Lins de Barros, P. Oliveira and I. Leal. 2001. Seasonal patterns in the orientation system of the migratory ant Pachycondyla marginata. Naturwissenschaften 88:343-346.


 * Hölldobler, B., E. Janssen, H. Bestmann, I. Leal, P. Oliveira, F. Kern and W. König. 1996a. Communication in the migratory termite-hunting ant Pachycondyla (= Termitopone) marginata (Formicidae, Ponerinae). Journal of Comparative Physiology A 178:47-53.




 * Mill, A. E. 1982a. Faunal studies on termites (Isoptera) and observations on their ant predators (Hymenoptera: Formicidae) in the Amazon Basin. Revista brasilera de Entomologia 26:253-260.


 * Roger, J. 1861a. Die Ponera-artigen Ameisen. Berliner Entomologische Zeitschrift 5:1-54.


 * Wajnberg, E., G. Cernicchiaro and D. Motta de Souza. 2004. Antennae: the strongest magnetic part of the migratory ant. BioMetals 17:467-470.


 * Wheeler, W. 1936. Ecological relations of ponerine and other ants to termites. Proceedings of the American Academy of Arts and Sciences 71:159-243.