Neoponera unidentata

A relatively common species that nests in hollow twigs (in vegetation and on the forest floor) and in rotten logs and stumps.

Identification
From Mackay and Mackay (2010): Pachycondyla unidentata can be separated from other members of the crenata species complex, including Pachycondyla crenata and Pachycondyla carinulata, as the highest point on the petiole is located near the anterior face (highest area about mid point in the latter two species). Pachycondyla unidentata can be separated from the Central and South American Pachycondyla striatinodis, as it lacks striae on all surfaces of the petiole (which are present in P. striatinodis). Rarely in P. unidentata a few striae may be present on the lower half of the side of the petiole. Pachycondyla unidentata is similar to the Colombian Pachycondyla recava, but differs in having the posterior face of the petiole convex and dull, not concave, smooth and glossy as in P. recava. Finally P. unidentata can be separated from the South American Pachycondyla goeldii, as the anterior face of the petiole is nearly vertical, not inclined to an approximately 45 degree angle as in P. goeldii. Pachycondyla unidentata is similar to Pachycondyla bugabensis, but can be separated as it lacks the depression at the metanotal suture on the dorsum of the mesosoma.

Workers of P. unidentata could be easily confused with workers of the Venezuelan Pachycondyla rugosula with the posterior face of the petiole being concave. They can be easily separated as the posterior face of the petiole is always convex, not flattened and strongly concave as in such workers of P. rugosula.

The workers of the new Costa Rican species Pachycondyla antecurvata could be confused with those of P. unidentata. They can be separated by the shape of the petiole. A poorly defined dorsal face is present in P. antecurvata with the highest point being at approximately the middle of the apex of the petiole, not near the anterior edge as in P. unidentata.

Distribution
Mexico through central South America, Trinidad.

Distribution based on Regional Taxon Lists
Neotropical Region: Belize, Bolivia, Brazil, Colombia, Costa Rica, Ecuador, French Guiana, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, Peru, Suriname, Trinidad and Tobago, Venezuela.

Habitat
Pachycondyla unidentata is a relatively common species found in habitats ranging from grasslands (Quiroz-Robledo and Valenzuela-González, 1995), to dry forest, primary rain forest, lowland rainforest, mature tierra firme forest, tropical evergreen forest and in a forest ravine, at elevations ranging from 20 - 1200 meters elevation. (Mackay and Mackay 2010)

Biology
From Mackay and Mackay (2010): This species nests in hollow twigs (in the vegetation and on the forest floor) and in rotten logs and stumps. A nest was found in litter on palm leaves. It occurs in areas with sandy soils and can be collected in leaf litter. Sexuals were found in nests in February - March (Costa Rica), March (Perú), May (British Guyana), June (Colombia, Perú, Brasil), July (Venezuela), July and August (México), August (Guatemala), September (Nicaragua, British Guyana), November (French Guiana) and December (Trinidad, Perú). Loose winged sexuals were collected in February (Perú), April (México), May (Costa Rica) and August (México). Wheeler (1918) reports that Beebe found dealate females in September in British Guyana. Other dealate females were collected in January (Guyana), June (Ecuador), August (Costa Rica) and November-December (Perú). It is very active and stings rather severely when handled (Wheeler and Bequaert, 1929). Foragers are found on low vegetation in the rainforest and can be collected in baits in the vegetation.

It nests in a number of plants, including a 1-meter tall Cordia nodosa [Boraginaceae], in C. hispidissima (Wheeler and Bequaert, 1929), in Cecropia membranacea [Cecropiaceae], and C. polystachya. It is common in the state of Chiapas, México, where it nests in the bulbous-based Tillandsia (Brown, 1957) [Bromeliaceae]. Wheeler (1942) reported it nesting in the petiolar swellings of Triplaris paniculata [Polygonaceae]. It was found nesting in the stems of Clibadium microcephalum (Compositae, Heliantheae), excavated by the beetle, Scolytodes elongates [Scolytidae] (Nesom and Stuessy, 1982). Specimens were collected in Costus laevis [Costaceae] (Schemske vouchers, LACM). These ants tend the extrafloral nectaries of the perennial monocot Calathea ovandensis (Horvitz and Schemske, 1990a) [Marantaceae]. This species lives in the epiphyte Tillandsia bulbosa (Dejean et al., 1995) [Bromeliaceae]. Several females were collected on Byttneria aculeata [Sterculiaceae] (Costa Rica). Specimens intercepted at the US border [USNM] were collected on bananas, philodendron, in bamboo and in Cattleya [Orchidaceae].

They have been collected in the stomach of Streptoprocne zonaris albicincta [white collared swift - Apodidae].

Nomenclature

 *  unidentata. Pachycondyla unidentata Mayr, 1862: 720 (w.q.) BRAZIL. Mackay & Mackay, 2010: 553 (m.). Combination in Neoponera: Emery, 1901a: 47; in Pachycondyla: Brown, in Bolton, 1995b: 311. Senior synonym of eburneipes, maya, trinidadensis: Brown, 1957e: 232.
 * eburneipes. Neoponera unidentata var. eburneipes Wheeler, W.M. & Bequaert, 1929: 29 (w.q.) BRAZIL. Junior synonym of unidentata: Brown, 1957e: 232.
 * maya. Neoponera unidentata var. maya Wheeler, W.M. & Bequaert, 1929: 30 (w.) GUATEMALA. Junior synonym of unidentata: Brown, 1957e: 232.
 * trinidadensis. Neoponera unidentata var. trinidadensis Wheeler, W.M. & Bequaert, 1929: 30 (w.) TRINIDAD. Junior synonym of unidentata: Brown, 1957e: 232.

Worker
From Mackay and Mackay (2010): The worker is a relatively small (total length about 6 mm) dark reddish brown ant with yellowish brown appendages. The anterior medial border of the clypeus forms a bluntly rounded to slightly angulate process. The region anterior to the eye is formed into a moderately well developed malar carina, the eye is relatively large, occupying nearly one third of the length of the side of the head. The antennal scape extends about the first 2 funicular segments past the posterior lateral corner. The pronotal shoulder forms a very sharp carina, which greatly overhangs the sides of the pronotum. The metanotal suture is barely evident on the dorsum of the mesosoma. The propodeal spiracle is elongated or oval-shaped. The petiole is thick when viewed in profile with the anterior face being nearly vertical, straight, or slightly concave, the posterior face being convex and rounded and meeting the anterior face at the anterior edge of the petiole. The posterior lateral margins of the petiole are sharp and usually form a crenulated carina. The metasternal process consists of two wide lobes, which terminate in small angles.

Erect hairs are abundant on most surfaces, including the dorsal and ventral surfaces of the head, the scape, dorsum of the mesosoma, the dorsum of the petiole and all surfaces of the gaster, the hairs on the tibiae are suberect.

The dorsum of the head is densely and evenly punctate, but shining between the punctures, the dorsum of the mesosoma is more finely punctate and more glossy, the sides of the pronotum are finely punctate and shiny, the remainder of the sides of the mesosoma is slightly more coarsely punctate, but is also shining between the punctures. The anterior face and sides of the petiole are finely punctate and glossy, the posterior face is very finely punctate and very smooth and glossy and the dorsum of the postpetiole is finely punctate and moderately glossy, as is most of the remainder of the gaster. The stridulatory file is well developed.

Queen
From Mackay and Mackay (2010): The female is similar to the worker, differing in being larger (total length about 9 mm) and is the same color. The anterior medial border of the clypeus is similar to that of the worker, the malar carina is well developed, the pronotal carina is also well-developed and overhangs the side of the pronotum, the spiracle and petiole are similar in shape to those of the worker.

The pilosity and sculpture are similar to that of the worker, except the dorsum of the gaster has more abundant appressed golden pubescence.

Male
From Mackay and Mackay (2010): The male (undescribed) is a relatively small (total length 6.2 mm) brown ant with yellowish brown legs and a yellowish brown tip of the gaster. The head length is 1.02 mm; the head width is 0.88 mm. The eyes are large (0.6 mm) and occupy more than half of the side of the head. The ocelli are large, with the median ocellus separated by approximately one diameter from the lateral ocellus (seen obliquely from above and from the side). The pronotum is only slightly swollen at the shoulder; the propodeal spiracle is slit-shaped. The petiole is thick when viewed in profile with a straight anterior face and a broadly rounded posterior face, the subpetiolar process is poorly developed and consists of an angulate lobe anteriorly with the remainder gradually diminishing in size posteriorly.

Erect hairs are abundant on the clypeus, the dorsal and ventral surfaces of the head, the posterior margin, the sides of the head, a few hairs are on the scape. The dorsum of the mesosoma has numerous erect hairs, as does the petiole and the gaster. The hairs on the legs are mostly erect, with the length being about ½ the width of the tibia.

The head, mesosoma, petiole and the gaster are finely punctate and moderately shining.

Type Material
Lectotype worker, 5 paralectotype workers, 1 paralectotype dealate female here designated, ; 1syntype worker seen, ; 1 cotype worker seen, ; 3 syntype workers seen, (Mackay and Mackay 2010)

Type Locality Information
Brasil, Amazonas; Brasil: Acre, Rio Branco; Guatemala Trece Aguas, Alta Vera Paz; Trinidad, Port of Spain (Mackay and Mackay 2010)

Etymology
The species name is based on two Latin words, unus, meaning one and dentatus, meaning toothed or pointed, possibly referring to the larger apical tooth of the mandible of the worker and female. It may be based on the anterior medial angle of the clypeus, which overhangs the anteclypeus. (Mackay and Mackay 2010)

Additional References

 * Dejean, A., I. Olmsted and R. Snelling. 1995. Tree-epiphyte-ant relationships in the low inundated forest of Sian Ka'an Biosphere Reserve, Quintana Roo, Mexico. Biotropica 27:57-70.


 * Horvitz, C. C. and D. W. Schemske. 1990. Spatiotemporal variation in insect mutualists of a Neotropical herb. Ecology 71:1085-1097.




 * Nesom, G. L. and Stuessy, T. F. 1982. Nesting of beetles and ants in Clibadium microcephalum S. F. Blake (Compositae, Heliantheae). Rhodora 84:117-124.


 * Quiroz-Robledo, L. and J. Valenzuela-González. 1995. A comparison of ground ant communities in a tropical rainforest and adjacent grassland in Los Tuxtlas, Veracruz, Mexico. Southwestern Entomologist 20:203-213.


 * Wheeler, W. M. 1918b. Ants collected in British Guiana by Mr. C. William Beebe. Journal of the New York Entomological Society 26:23-28.


 * Wheeler, W. 1942. Studies of Neotropical ant-plants and their ants. Bulletin of the Museum of Comparative Zoology 90:1-262 + 57 plates.


 * Wheeler, W. and J. Bequaert. 1929. Amazonian myrmecophytes and their ants. Zoologischer Anzeiger 82:10-39.