Neoponera crenata

From Mackay and Mackay (2010): This species usually nests in hollow twigs, including in bamboo, but can be found in damaged areas of living trees and in logs and in trunks.

Identification
From Mackay and Mackay (2010): Workers of P. crenata could be easily confused with Pachycondyla moesta, which is found from Guatemala south to Argentina. The shape of the petiole as seen from above is the best character to separate the two species. Pachycondyla crenata has the petiole strongly narrowed anteriorly (seen from above), whereas it is blunt and rounded in P. moesta. The worker of P. crenata can often be separated from that of P. moesta as the malar carina is more developed, as is the pronotal carina and the dorsal face of the propodeum slopes downward anteriorly. The malar and pronotal carinae are poorly developed in P. moesta and the dorsum of the petiole forms a convex horizontal surface. Pachycondyla crenata can be separated from the other members of the crenata species complex, as the pronotal carina is not as sharp and does not extend over the side of the pronotum (seen from behind).

Wheeler and Wheeler (1974) provide characteristics to separate the larvae of P. crenata from those of P. moesta. Pachycondyla crenata is similar to the Paraguayan Pachycondyla fiebrigi and Brasilian Pachycondyla latinoda, but differs in being smaller (the total length of the other two is 8.5 - 10 mm) and in having a relatively longer petiolar node (0.55 mm in length, 0.65 mm in width, versus length 0.7 mm, width 1.05 mm in P. fiebrigi). Pachycondyla crenata (as well as the related species) could be confused with Pachycondyla holcotyle as the petioles are very similar in shape. Pachycondyla crenata can be easily separated by the presence of a malar carina (absent in P. holcotyle) and the lack of striae on the side and petiole (present in P. holcotyle).

The relatively small size, the brown color, together with the thick petiole, would separate the male of P. crenata from most of the others in the genus. Pachycondyla crenata males would be most likely confused with males of P. moesta, but can be separated as males of P. moesta lack the concave region on the lower surface of the petiole. Additionally the clypeus is less swollen in P. crenata and does not overhang the anterior edge of the clypeus as it does in P. moesta. The apex of the petiole is broadly rounded in P. crenata, not angulate as in P. moesta. The third discoidal cell of the wing of P. crenata is not as long (longest diagonal length of cell 0.41 mm) and is strongly narrowed anteriorly as compared to the third discoidal cell of P. moesta (length 0.63 mm). Both Longino (website) and Wild (2005) consider P. crenata to be a variable species or possibly a species complex. Once P. moesta, Pachycondyla globularia, P. latinoda and P. fiebrigi are recognized as being different, it becomes much more homogeneous.

Distribution
Central America through central South America (Mackay and Mackay 2010)

Habitat
This species occurs in wet forest and rain forest, secondary rain forest, a guava plantation, a cacao plantation and disturbed areas, between 5 - 1700 meters and in grasslands (Quiroz-Robledo and Valenzuela -González, 1995). (Mackay and Mackay 2010)

Biology
From Mackay and Mackay (2010): One nest was in a damaged guava tree, still containing beetle larvae, four meters from the ground. Colonies are usually small, with fewer than 20 workers. One complete nest had a single queen. Brood was collected in nests in July (Nicaragua), August (Costa Rica) and December (Colombia). Males and females were collected in nests in April and May (México), July (Ecuador) and September (Costa Rica). An alate female and a loose male were collected in July (Costa Rica). A dealate queen with brood was found in July (Nicaragua). An alate female was collected in a malaise trap in November (Colombia). Specimens are often collected in extractions of sifted leaf litter, mold and rotten wood. Workers can be seen foraging on trees and vegetation.

Workers are extremely fast and often exit the nest without taking the brood when a nest is collected. It is difficult to collect many specimens. One captured worker was unable to penetrate a finger with the stinger. Colonies from French Guiana were nesting in the ant-plant genus Tococa [Melastomataceae]. Data labels state they are found in Tococa formicaria and Cecropia insignis. Specimens from Colombia and Venezuela were intercepted on Catleya [Orchidaceae] orchids [USNM]. Wheeler (1942) found this species nesting in the domatia of Cordia alliodora [Boraginaceae] (P. moesta), in the petiolar swellings of Triplaris paniculata [Polygonaceae], in the branches of Cecropia sciadophylla var. decurrens [Cecropiaceae] (P. crenata [= Pachycondyla stipitum]), in dried fruit of Bromelia fastuosa [Bromeliaceae] and B. epiphytica (P. crenata and Pachycondyla moesta), in hollow petioles of Tachigalia paniculata [Leguminosae], in cauline swellings of Cordia gerascanthus and in bamboo, occupying the nests made by the ant Camponotus alboannulatus (P. crenata and P. moesta). This species lives in the epiphyte Tillandsia bulbosa [Bromeliaceae] (Dejean et al., 1995).

Worker
From Mackay and Mackay (2010): The worker is a relatively small ant (total length about 6 mm) reddish brown with pale brown appendages. The anterior medial region of the clypeus is bluntly protuberant; the eyes are very large (maximum diameter 0.36 mm), about three times in diameter as the length between the anterior border and the anterior margin of the head (side view). A poorly defined malar carina is located between the eye and the clypeus. The pronotal carina is present, but poorly developed, the metanotal suture barely breaks the integument on the dorsum of the mesosoma. The propodeal spiracle is elongated; the petiole is thickened when viewed in profile and somewhat cuboidal-shaped with the anterior and posterior faces being nearly parallel and with a definite dorsal face. The anterior face is straight, the dorsal face and the posterior face are convex and rounded. The petiole is strongly narrowed anteriorly (viewed from above). The stridulatory file is present on the second pretergite on the dorsum of the gaster, but is poorly developed. Erect hairs are abundant on the dorsal and ventral surfaces of the head, the dorsum of the mesosoma, the dorsal and posterior faces of the petiole and all surfaces of the gaster; the hairs on the tibiae are mostly suberect. Appressed pubescence is mostly sparse, a few hairs are present on the head, dorsum of the mesosoma, dorsum of the petiole and dorsum of the gaster, where they are moderately abundant.

The head and the dorsum of the mesosoma are punctate, appearing like the surface of a thimble, the side of the pronotum is weakly punctate and moderately smooth and glossy, the mesopleuron is mostly smooth and glossy, the side of the propodeum has poorly defined striae and is weakly shining. The petiole is punctate on the sides and the top, the posterior face is mostly smooth and glossy, the dorsum of the gaster is finely punctate and moderately smooth and glossy.

Queen
From Mackay and Mackay (2010): The female is a small (total length 7 - 8 mm) reddish brown ant with slightly lighter colored appendages. The mandibles have approximately 11 teeth; the clypeus has a lobed medial process which overhangs the anteclypeus. The surface of the process is longitudinally concave. The malar carina is well developed and extends completely to the eye, which is large (maximum diameter 0.5 mm) and located about ½ diameter from the anterior margin of the head. The scape extends approximately the first funicular segment past the posterior lateral corner of the head. The carina on the pronotal shoulder is sharp and well developed and overhangs the side of the pronotum. The petiole is thick when viewed in profile and noticeably narrowed anteriorly when viewed from above. The subpetiolar process is poorly developed and forms a ventrally directed sharp angle followed by a concave region and finally by a swollen region approximately in the middle of the surface. The wing is typical for the genus, but with the third discoidal cell being somewhat elongated.

Relatively short (0.1 mm) erect hairs are abundant on most surfaces of the mandibles, dorsal and ventral surfaces of the head, scapes, mesosoma, petiole and gaster, the hairs on the legs are mostly suberect. Fine appressed whitish pubescence is present on the dorsum of the head, dorsum of the mesosoma, dorsum and anterior face of the petiole and all surfaces of the gaster.

The mandibles are finely striated with scattered punctures, the median lobe of the clypeus has fine longitudinal striae, the frontal lobes and dorsum of the head are covered with dense coarse punctures, the pronotum and dorsum of the remainder of the mesosoma have similar punctures, the sides of the mesosoma have a mixture of punctures with striae, the petiole is slightly punctated as is the gaster, most surfaces are dull to moderately shining, the posterior face of the petiole is smooth and glossy.

Male
From Mackay and Mackay (2010): The male is a small (total length 5 mm) brown specimen. The anterior border of the clypeus is straight or slightly convex, the clypeus is swollen medially, but does not form an angulate structure and the eyes are large, occupying more than ½ of the sides of the head. The medial ocellus is intermediate in size (Brasil, maximum diameter 0.11 mm) to large (Costa Rica, maximum diameter 0.16 mm), the lateral ocelli extend slightly past the posterior lateral margin of the head (Brasil) or well beyond (Costa Rica). The location of the malar carina is slightly raised, but a definite carina is not evident. The pronotal shoulder is not swollen into a carina. The propodeal spiracle is slit-shaped. The petiole is broad when viewed in profile with a rounded apex. The subpetiolar process is characteristic of this species and is formed by a sharp anterior angle, a concave surface and a posterior swollen region. The wing is similar to that of the female.

Erect hairs are sparse, a few are present between the eye and the lateral ocellus, on the clypeus, on the dorsum of the mesosoma, dorsum of the petiole and all surfaces of the gaster, most hairs on the legs are suberect. Appressed pubescence is present on the head, the dorsum of the mesosoma, anterior and dorsal faces of the petiole and all surfaces of the gaster.

The surface of the head is finely coriaceous and moderately to strongly shining, the dorsum of the mesosoma is finely coriaceous to punctate or with poorly defined striae and moderately shining, the side of the pronotum is nearly glossy and shining, as is the mesopleuron, the side of the propodeum is irregularly striate and dull. The petiole is finely sculptured and at least moderately to strongly shining. The gaster is coriaceous and shining.

Etymology
The name of this species is based on the Latin word crenatus, meaning toothed, possibly referring to the angulate medial clypeal process which overhangs the anteclypeus of the worker (and female) of this species. (Mackay and Mackay 2010)