Neoponera aenescens

Workers of this species are fast and wary. Few nests of this species have been found. Most specimens have been collected from pitfall traps and litter samples.

Identification
From Mackay and Mackay (2010):

The workers of P. aenescens could be confused with Pachycondyla harpax but can be easily separated as the metanotal suture of P. harpax does not break the integument on the dorsum of the mesosoma. Pachycondyla aenescens differs from Pachycondyla carbonaria in lacking the shiny appearance of the dorsum of the head and the pronotum although bluish or greenish reflections may be present. Pachycondyla aenescens is very similar to Pachycondyla schoedli. It can be separated by the roughly sculptured and dull mesopleuron, which is smooth and glossy in P. schoedli. The shape of the petiole would separate P. aenescens from Pachycondyla fisheri and Pachycondyla luteola, in which the petiole is not narrowed gradually toward the apex. The shape of the petiole would separate P. aenescens from several other species including Pachycondyla striata, Pachycondyla impressa and Pachycondyla crassinoda in which the petiole is rectangular-shaped. Pachycondyla aenescens could be confused with Pachycondyla eleonorae and Pachycondyla fauveli, but differs in that the petiole is broader than long when viewed from above (longer than broad P. eleonorae and P. fauveli).

The female of P. aenescens would probably be nearly identical to what would be expected of the female of Pachycondyla emiliae (unknown), probably differing in having a concave medial border of the clypeus (expected to be completely convex in the unknown female of P. emiliae based on the form of the worker). The propodeal spiracle may be circular in the female of P. emiliae, not elongated as in P. aenescens. Otherwise they would be expected to be similar, especially as the shape of the petiole of the female of P. aenescens is identical to that of the worker of P. emiliae. This shows the apparent close relationship between the aenescens and crassinoda species complexes and the lack of importance of the shape of the propodeal spiracle in the phylogeny of the species of Pachycondyla.

Two workers of P. aenescens in the LACM (Trujillo, Venezuela, via Boconó Guaramacal, Parque Laguna de los Cedros, 12-vi-1986, J. Lattke) are somewhat intermediate between P. schoedli and P. aenescens, but are considered to be P. aenescens as they have punctate heads (but smoother and more shining with less dense punctures than the typical P. aenescens) and the mesopleuron is completely striate, not mostly smooth as in P. schoedli.

Distribution
Nicaragua, Costa Rica, Panama, Colombia, Ecuador, Peru, Venezuela.

This taxon was described from Colombia.

Habitat
These ants have been collected in wet tropical rain and cloud forest, montane forest, to dry oak forest at 1150 - 2300 m.

Biology
Mackay and Mackay (2010): "One colony was nesting under a stone. Alate females were collected in a nest in August (Colombia). Loose winged sexuals were collected in June (Panamá), July (Costa Rica [Forel, 1908]), between January and July (Ecuador, canopy fogging), August (Costa Rica) and December (Ecuador). Dealate females were extracted from litter in June (Costa Rica, Panamá), others were collected in October (Perú) and December (Colombia). Three dealate females were collected in a rotten log, suggesting pleometrosis (multiple females forming a new nest). These ants are parasitized by Apocephalus constrictus'' (Phoridae)."

Costa Rica
Longino, Ants of Costa Rica: "This species is a common inhabitant of cloud forest habitats, where it is usually the only large, conspicuous Pachycondyla. I have often observed foraging workers on roads and trails. Workers may be seen foraging day or night. Most of my collections are from sifted litter samples from the forest floor leaf litter. I once observed an alate queen high in the canopy of a large oak tree in Monteverde.

Nomenclature

 *  aenescens. Pachycondyla aenescens Mayr, 1870a: 396 (w.) COLOMBIA. Emery, 1890b: 42 (q.); Forel, 1899c: 10 (m.). Combination in Euponera (Mesoponera): Emery, 1901a: 47; in Mesoponera: Kempf, 1972a: 141; in Pachycondyla: Brown, in Bolton, 1995b: 302. See also: Mackay & Mackay, 2010: 194.

Worker
From Mackay and Mackay (2010): The worker is a moderate sized ant (total length about 9 mm). The anterior border of the clypeus is indented medially with the region depressed; the eye is relatively large and is located about one diameter from the insertion of the man-dible (side view). The scape extends about two funicular segments past the posterior lateral corner of the head. The malar carina is not developed anterior to the eye, but is represented by a swollen region near the base of the mandible. The pronotal shoulder is swollen and nearly forms a carina; the metanotal suture is depressed on the dorsum of the mesosoma and divides the integument. The petiole is noticeably narrowed toward the apex. The stridulatory file is present on the dorsum of the gaster. The metasternal process consists of two widely spaced triangular lobes, similar to those of P. schoedli and P. fauveli.

Erect hairs are moderately abundant on all surfaces including the dorsum of the mesosoma and the petiole. Erect hairs are absent or sparse (1 - 2) on the scape. Most of the mandible is roughly sculptured, but it is smooth and shiny near the apex. The head and mesosoma are mostly punctate with some evidence of striae, especially on the medial part of the clypeus (longitudinal), the dorsum of the head, the mesopleuron and the side of the propodeum. The petiole is finely punctate and some areas, especially the posterior face, are partially smooth and shiny. The gaster is very finely sculptured and mostly shiny.

The worker is mostly black with the appendages slightly lighter in color.

Female
From Mackay and Mackay (2010): The female is a large (total length 12 - 13 mm) black ant, similar to the worker, with the malar carina being slightly developed near the base of the mandibles. The mandibles have about 12 teeth, with alternating large and small teeth. The anterior border of the clypeus is convex, but with the medial section being notably concave. The eyes are large, with the maximum diameter (0.5 - 0.7 mm) being greater than the distance to the anterior edge of the head (side view). The ocelli are small (lateral 0.08 mm - maximum diameter of medial ocellus 0.13 mm); the medial ocellus is located about two diameters from the lateral ocellus. The scape (2.76 mm) extends nearly the first two funicular segments past the posterior lateral corner. The pronotal shoulder is swollen and nearly forms a carina; the propodeal spiracle is elongated. The shape of the petiole is quite different from that of the worker, being narrower with a slightly concave anterior face and a broadly rounded posterior face, which meets the anterior face at the anterior edge. The posterior lateral margins are sharp. The subpetiolar process consists of a thick lobe.

Erect hairs are scattered on most surfaces, moderately long (most about 0.2 mm in length, a few up to 0.6 mm) and are present on the mandibles, clypeus, dorsal and ventral surfaces of the head, sides of the head, the scape has a few scattered suberect hairs, moderately abundant erect hairs are present on the mesosoma, petiole and gaster; the hairs on the legs are mostly suberect.

The mandibles are finely striate, with scattered elongate punctures, the middle of the clypeus is longitudinally striate, the dorsum of the head is finely and densely punctate, the sculpture on the dorsum of the mesosoma is similar, except the punctures are coarser on the pronotum, the sides of the mesosoma are mostly finely striolate and moderately shining, the petiole is finely punctate and shining, as is the gaster.

Male
From Mackay and Mackay (2010): The male is a large (total length 12 mm) black ant. The anterior clypeal border is weakly convex and not concave medially as in the worker and female (a probable male from Tiputini, Ecuador has a concave anterior border). The mandibles are tiny. The ocelli are large, approximately as large as the length between them. The petiole is thick when viewed in profile, with a rounded apex.

Erect hairs are sparse with a few on the dorsum of the head, several on the ventral surface of the head, scattered on the mesosoma, petiole and gaster. Appressed pubescence is very fine and abundant on all surfaces, giving the surfaces a pruinose appearance.

Surfaces are coriaceous or finely punctate, but weakly shining.

Type Material
Lectotype worker, 13 paralectotype workers, 3 paralectotype males seen, NHMW (Mackay and Mackay 2010)

Type Locality Information
Colombia (Mackay and Mackay 2010)

Etymology
The name of this species comes from the Latin word aeneus, which means brazen and refers to the color. (Mackay and Mackay 2010)

Additional References
Mayr, G. 1870. Formicidae novo-granadensis. Sitzungsberichte der k. Akademie der Wissenschaften. Mathematisch-Naturwissenchaftliche Classe 61:370-417.