Neoponera obscuricornis

In the published literature this species often referred to this species as the more common Pachycondyla verenae. Any accounts in regards to its biology are thus suspect due to this confusion about its identification.

Identification
From Mackay and Mackay (2010): Wild (2005) cleared the confusion regarding the identity of P. obscurecornis. The worker of P. obscuricornis would be most easily confused with that of the common and widely distributed Pachycondyla verenae. Pachycondyla obscuricornis can be easily separated as the posterior lateral edge of the petiole does not sharply differentiate the lateral and posterior faces of the petiole, as it does in P. verenae. Additionally P. obscuricornis has dense appressed pubescence on the hypopygium, which is lacking or greatly reduced in P. verenae. The shape of the metasternal process of P. obscuricornis would also separate this species from P. verenae, in which the separation of the lobes is not concave apically, as it is in P. verenae and it lacks the oblique striae, which are apparently always present in P. verenae. Pachycondyla obscuricornis is more closely related to Pachycondyla apicalis than it is to P. verenae. It can be easily separated from P. apicalis as P. obscuricornis lacks the yellow-tipped funiculus. The lack of erect hairs on the dorsum of the mesosoma would separate P. obscuricornis from the similar Pachycondyla cooki.

Wild (2002) lists a species near P. obscuricornis, which is the true P. obscuricornis (Wild, pers. comm.); the P. obscuricornis listed in Wild (2002) are actually P. verenae (Wild, pers. comm.).

Distribution
ECUADOR, PERU, BRASIL, BOLIVIA, PARAGUAY. (Mackay and Mackay 2010)

Distribution based on Regional Taxon Lists
Neotropical Region: Bolivia, Brazil, Costa Rica, Ecuador, French Guiana, Guyana, Mexico, Panama, Paraguay, Suriname.

Habitat
Pachycondyla obscuricornis can be found in rainforest, subtropical tall forest and at the edge of second growth rain forest at 0 - 700 m (Wild, 2005). One series from Ecuador was collected at 1100 m. It is a rarely collected rain forest ant (Wild, 2005). (Mackay and Mackay 2010)

Nomenclature

 *  obscuricornis. Pachycondyla flavicornis var. obscuricornis Emery, 1890a: 58 (w.) BRAZIL. Combination in Neoponera: Emery, 1901a: 47; in Pachycondyla: Brown, in Bolton, 1995b: 308. Raised to species: Emery, 1911d: 72. See also: Wild, 2005: 9; Mackay & Mackay, 2010: 479.

Worker
From Mackay and Mackay (2010): The worker is a moderate sized (total length 10 - 11 mm) black ant with brown appendages, including the funiculus. The mandibles have approximately 10 teeth, in addition to several smaller denticles located between the teeth. The anterior margin of the clypeus is convex but the anterior medial margin is concave. The malar carina is present and nearly reaches the eye. The eye is large (maximum diameter 0.8 mm) located less than one maximum diameter from the anterior margin of the head (side view). The eyes are located slightly posteriorly on the head. The antennal scapes are moderately long (2.2 mm) and extend approximately the first two funicular segments past the posterior corner of the head. The posterior margin of the head is slightly concave; the posterior lateral corners are slightly angulate. The pronotal carina is poorly developed, the metanotal suture is well developed, breaking the sculpture on the dorsum of the mesosoma and noticeably depressing the mesosoma when viewed in profile. The propodeal spiracle is slit-shaped. The anterior face of the petiole is broadly rounded into the dorsal face, the posterior face is nearly vertical and the dorsal face is broadly rounded, the posterior lateral margins of the posterior face are poorly developed. The subpetiolar process is relatively small and consists of a small anterior lobe with a ventrally and posteriorly directed tooth, the remainder of the process is poorly developed. The metasternal process consists of two elongate triangular lobes.

Erect hairs are sparse with a few present on the frontal carina, the clypeus, the mandibles, hairs are absent on most of the dorsal and ventral surfaces of the head, the posterior margin, the sides of the head, the scapes (except at the apex), absent on the dorsum of the mesosoma, the dorsum of the petiole and the dorsum of the gaster, a few tiny hairs are present on the subpetiolar process and the ventral surface of the gaster. A few hairs are present on the coxae, but are mostly absent on the remainder of the legs.

The mandibles are finely striate; the remainder is mostly very finely punctate and dull.

Queen
Queens are not known for this species.

Male
Males are not known for this species.

Type Locality Information
Brasil, Pará (Mackay and Mackay 2010)

Etymology
The name of this species is derived from two Latin words, obscurus, meaning dark and cornus, meaning horn, referring to the dark funiculus of the worker. (Mackay and Mackay 2010)

Additional References

 * Emery, C. 1890a. Voyage de M. E. Simon au Venezuela. Annales de la Société Entomologique de France 10:55-76.


 * Gobin, B., J. Heinze, M. Straetz and F. Roces. 2003. The energetic cost of reproductive conflicts in the ant Pachycondyla obscuricornis. Journal of Insect Physiology 49:747-752.


 * Lommelen, E., E. Schoeters and J. Billen. 2002. Ultrastructure of the labial gland in the ant Pachycondyla obscuricornis (Hymenoptera, Formicinae). Netherlands Journal of Zoology 52:61-68.




 * Morgan, E., R. do Nascimento, S. Keegans and J. Billen. 1999. Comparative study of mandibular gland secretions of workers of ponerine ants. Journal of Chemical Ecology 25:1395-1409.


 * Morgan, E., H. Jungnickel, S. Keegans, R. do Nascimento, J. Billen, B. Gobin and F. Ito. 2003. Comparative survey of abdominal gland secretions of the ant subfamily Ponerinae. Journal of Chemical Ecology 29:95-114.


 * Wild, A. 2002. The genus Pachycondyla (Hymenoptera: Formicidae) in Paraguay. Boletín del Museo Nacional de Historia Natural de Paraguay 14:1-18.


 * Wild, A. 2005. Taxonomic revision of the Pachycondyla apicalis species complex (Hymenoptera: Formicidae). Zootaxa 834:1-25.