Neoponera obscuricornis

This rarely-encountered species appears to be a rainforest ant. The collection elevations run from around sea level to 700 meters. The records from San Martín Peru and Santa Cruz Bolivia are from rainforest, the Paraguayan specimens were collected as ground foragers in primary humid subtropical tall forest, and the Ecuadorian record is from the edge of a second growth rainforest. The single nest series, collected by Phil Ward in Davidcillo, 30 km NNE Tarapoto in San Martín, Peru, was in a rotting log. (Wild, 2005)

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

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

Biology
In most published literature that includes this species name the actually species referenced is the more common Pachycondyla verenae (=Neoponera verenae). Wild's 2005 account of the biology of this species is prefaced by: "Nearly all the information published under the name P. obscuricornis actually refers to P. verenae. Little is known about the biology of true P. obscuricornis."

Castes
Known only from the worker caste.

Nomenclature

 *  obscuricornis. Pachycondyla flavicornis var. obscuricornis Emery, 1890a: 58 (w.) BRAZIL. Combination in Neoponera: Emery, 1901a: 47; in Pachycondyla: Brown, in Bolton, 1995b: 308; in Neoponera: Schmidt & Shattuck, 2014: 151. 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.

Type Material
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)