Pseudoponera gilberti

From Mackay and Mackay (2010): One colony was found in a well-rotted Nasutitermes nest on the forest floor, another in the soil under leaf litter. A colony was collected in rotten wood in Perú in a site with sandy soil. A specimen was extracted from a soil sample and a second worker was extracted from palm flower litter. A dealate female was collected in July (Ecuador) in a statry bivouac site of the army ant Eciton burchellii just after emigration. Other females were collected in February and December (Kempf, 1960a).

Identification
From Mackay and Mackay (2010): The worker and female of P. gilberti are essentially identical to those of Pachycondyla stigma, as both species have a broadly rounded subpetiolar lobe and six mandibular teeth. The major difference between them is that the transverse carina on the clypeus of P. gilberti is well developed, but only poorly developed or nearly absent in P. stigma. Pachycondyla gilberti is also similar to Pachycondyla succedanea, but can be distinguished as the posterior edge of the subpetiolar process is rounded, not angulate as in P. succedanea.

Separation of the males of P. gilberti from those of P. stigma is difficult. The smaller medium brown specimens can be separated from the larger dark brown males of P. stigma. The large dark males of P. gilberti appear to be indistinguishable from similar males of P. stigma.

Distribution
Southern Central America through central South America, Trinidad. (Mackay and Mackay 2010)

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

Habitat
Pachycondyla gilberti was found in the transition between tierra firme and seasonally flooded forest clearing in secondary forest, from 0 to 325 meters. (Mackay and Mackay 2010)

Nomenclature

 *  gilberti. Trachymesopus gilberti Kempf, 1960f: 425, fig. 6 (w.q.) BRAZIL. Wheeler, G.C. & Wheeler, J. 1971b: 1206 (l.); Mackay & Mackay, 2010: 344 (m.). Combination in Mesoponera: Wheeler, G.C. & Wheeler, J. 1971b: 1206; in Pachycondyla: Brown, in Bolton, 1995b: 305.

Worker
From Mackay and Mackay (2010): The worker is a small (total length 5 mm) dark reddish brown ant. The mandibles have 6 teeth. The transverse carina on the clypeus is well developed and a longitudinal medial area is swollen, but does not form a carina. The head is narrowed anteriorly and the posterior border is concave. The eye is small (maximum diameter 0.07 mm) located slightly more than 1 diameter from the anterior margin of the head. The scape is short and barely reaches the posterior lateral corner of the head. The pronotal shoulder is rounded, the promesonotal and metanotal sutures are marked on the dorsum of the mesosoma, but neither is greatly depressed when the mesosoma is viewed in profile. The propodeal spiracle is nearly circular. The petiole is narrow when viewed in profile and constricted toward the apex, forming a rounded surface. The subpetiolar process is broadly rounded and lobe-shaped.

Erect hairs are mostly short (about 0.1 mm in length, although hairs on the clypeus may be 0.25 mm in length) and are present on the mandibles, clypeus, dorsal and ventral surfaces of the head, antennal scapes, mesosoma, petiole, gaster and legs; appressed whitish pubescence is abundant on the head, mesosoma and gaster. The mandibles are smooth and moderately glossy with scattered punctures, the dorsum of the head is finely punctate and dull, the dorsum of the mesosoma has similar punctures, the sides are finely striate, most surfaces are at most weakly shining, the gaster is finely punctate and moderately shining.

Queen
From Mackay and Mackay (2010): The female is a small (total length 4 mm) reddish brown ant with lighter colored appendages. The mandible has six teeth with a small swelling near the basal border, which does not form a tooth. The anterior margin of the clypeus is convex and the clypeus has a transverse sharp ridge or carina, which is elevated over the anteclypeus. The head is narrowed anteriorly and posteriorly and the posterior border is slightly concave. The eye is large and separated from the anterior margin of the head by less than ½ of the greatest eye diameter (side view). The scape reaches or extends slightly past the posterior lateral corner of the head. The pronotal shoulder is without a carina; the propodeal spiracle is circular or elliptical. The propodeum is angulate between the dorsal face and the posterior face. The petiole is slender when viewed in profile and the subpetiolar process consists of a large broadly rounded lobe.

Erect hairs are present on the mandibles, dorsal and ventral surfaces of the head, the side of the head anterior to the eyes, the shaft of the scape, dorsum of the mesosoma, dorsum of the petiole, subpetiolar process and all surfaces of the gaster. The hairs on the legs are erect or suberect, with several on all surfaces of the tibiae. Most surfaces, except for the mandibles, are covered with an appressed pubescence, which is abundant to very abundant and obscures some of the surfaces, especially the dorsum of the head, dorsum of the mesosoma and dorsum of the gaster.

The mandibles are smooth and shining with scattered punctures, the remainder of the surfaces is dull and punctate; the gaster is weakly shining.

Male
From Mackay and Mackay (2010): The male (undescribed) is a small (total length 3.5 - 5.0 mm) medium brown to dark brown specimen with yellow to medium brown legs and antennae. The head length is 0.78 - 0.83 mm, the head width is 0.76 - 0.85 mm. The anterior margin of the clypeus is broadly concave; the eyes are large (maximum diameter 0.40 - 0.44 mm). The Mayrian furrows are present, but do not meet and the parapsidal sutures are well developed. The petiole is narrow when viewed in profile and the subpetiolar process consists of a broadly rounded lobe. Males apparently come in two forms: smaller medium brown specimen and larger dark brown specimen, but this conclusion is based on only a few specimens.

Erect hairs are sparse with a few on the dorsal surface of the head and clypeus, sides of the head anterior to the eyes, between the lateral ocelli, on the dorsum of the mesosoma, dorsum of the petiole, subpetiolar process and all surfaces of the gaster. Nearly all of the hairs on the legs are appressed. Appressed pubescence is sparse and mostly restricted to the head, dorsum of the mesosoma and all surfaces of the gaster. Most surfaces are punctate, but the mesosoma and gaster are weakly shining.

Type Material
Female paratype seen, (Mackay and Mackay 2010)

Type Locality Information
Brasil: São Paulo: Agudos (Mackay and Mackay 2010)

Etymology
This species was named in honor of Father Columbano Gilbert, Professor of French and German of the Franciscan Seminary at Agudos, Brasil, 1914 – 2002, an “industrious discover of many myrmecological rarities” (Kempf, 1960a). (Mackay and Mackay 2010)

Additional References

 * Kempf, W. 1960a. Miscellaneous studies on Neotropical ants (Hymenoptera: Formicidae). Studia Entomologica 3:417-466.