Pachycondyla fuscoatra

From Mackay and Mackay (2010): Most specimens were collected in pitfall traps, a few from Winkler extractions. Otherwise, nothing is known of this rarely collected species.

Identification
From Mackay and Mackay (2010): There has been considerable uncertainty in the identity of P. fuscoatra, as the types were apparently destroyed in World War II. It is closely related to Pachycondyla impressa (Roger, 1861a). Emery (1890a) separated P. fuscoatra from P. impressa as having punctate and rugose sculpturing on the head and the mesosoma and the surfaces being opaque. The similar surfaces of P. impressa are punctate but are shining. Kempf (1961) criticized Emery for the use of such poor characters when a number of good characters were available to separate the two species. Kempf (1961) separated them on the basis of the fewer mandibular teeth (5 - 6) in P. fuscoatra, as compared to numerous teeth (8 - 9) in P. impressa. Additionally the pygidium of P. fuscoatra is without lateral rugae and without a posterior medial dorsal impression, both of which are present in P. impressa. Kempf (1961) further stated that Emery confused his successors with his poor characters, which resulted in the naming of a number of varieties of P. fuscoatra, which Kempf considered to be synonyms of P. impressa.

The specimens we are considering to be P. fuscoatra agree reasonably well with Roger's description and are not any of the other Neotropical species. They are larger than P. impressa, as Roger states. The head and dorsum of the mesosoma are densely rugose or striate with the posterior face transversely striate as stated in Roger’s description. The petiole of P. fuscoatra is slightly narrower than that of P. impressa and the gaster is glossy, all listed in the original description. Roger (1861a) clearly states that the mandibles of P. fuscoatra have 5 or 6 teeth. This is true in the specimens we examined, if one disregards the smaller teeth and denticles that are spaced between the larger teeth.

Pachycondyla fuscoatra can be recognized in the field or without a microscope by the glossy gaster, with the remainder of the ant appearing dull. Pachycondyla fuscoatra could be easily confused with the widely distributed and common P. impressa, but can be separated as the pygidium is not depressed and the sides of the pygidium are smooth and punctate, not striate as in P. impressa. Pachycondyla impressa also lacks the coarse striae on the dorsum of the head. These striae on P. fuscoatra could result in confusion with Neoponera lineaticeps (México to Panamá), which has similar striae. Pachycondyla fuscoatra is much larger and the striae on the head of N. lineaticeps are mostly confined to the middle of the dorsum of the head. Neoponera magnifica from Brasil also has coarse striae on the dorsum of the head, but the pronotum is coarsely and longitudinally striate, not finely striate as in P. fuscoatra.

The striae on the dorsum of the head could cause confusion with Pachycondyla striata. The striae on the head of workers and females of P. fuscoatra are coarse, but are fine and difficult to see in P. striata. The differences in the distributions would also be useful, with P. fuscoatra being rare and found in northern South America, P. striata being common and found in the southern half of South America. The shining gaster of the worker and female of P. fuscoatra is similar to that of Pachycondyla lattkei from Venezuela. The striae on the head and dorsum of the pronotum of P. lattkei are very fine and not obvious. The anterior face of the postpetiole of P. fuscoatra is concave and angulate between the anterior and dorsal face, whereas it is not concave and is broadly rounded between the faces of P. lattkei.

Distribution
COLOMBIA, VENEZUELA (Mackay and Mackay 2010)

Distribution based on Regional Taxon Lists
Neotropical Region: Bolivia, Brazil, Colombia, Costa Rica, Ecuador, Venezuela.

Habitat
Specimens are found in mature and secondary rain forest, 1500 - 2050 meters elevation. (Mackay and Mackay 2010)

Nomenclature

 *  fuscoatra. Ponera (Pachycondyla) fuscoatra Roger, 1861a: 8 (w.) COLOMBIA. Mackay & Mackay, 2010: 339 (q.). Combination in Pachycondyla: Mayr, 1863: 439.

Worker
From Mackay and Mackay (2010): The worker of this species is a large (total length 13 mm) black ant with partially brown appendages. The mandibles are long with 5 or 6 well-developed teeth, as well as 4 or 5 smaller teeth or denticles. The anterior border of the clypeus is broadly rounded and slightly concave medially. The head length is 2.7 mm; the head width is 2.6 mm. The malar carina is absent and the eye is relatively small (maximum diameter 0.35 mm) located slightly more than one eye diameter from the anterior margin of the head. The scape (2.3 mm) extends slightly past the posterior lateral corner of the head. The sides of the head are nearly straight and slightly diverge anteriorly; the posterior border is strongly concave. The pronotal shoulder is rounded with little evidence of a swelling; the metanotal suture is poorly marked on the dorsum of the mesosoma and does not break the sculpture and the propodeal spiracle is slit-shaped. The anterior and posterior faces of the petiole are nearly parallel and the dorsal face is well developed, the anterior face is slightly concave, the posterior face convex. The subpetiolar process is poorly developed and consists of a swollen region, sometimes with a tiny anterior ventrally directed tooth. The anterior face of the postpetiole is slightly concave and meets the dorsal face and nearly a right angle. The stridulatory file is absent on the second pretergite, as are the arolia between the tarsal claws.

Erect hairs are present on the mandibles, clypeus, dorsal and ventral surfaces of the head, scape, dorsum of the mesosoma, petiole and all surfaces of the gaster; most hairs on the legs are suberect. Appressed pubescence is sparse, but present on the head, the mesosoma and the gaster.

The entire dorsum of the head is covered with coarse striae or rugae, which extend on the sides well past the eyes. The anterior ½ of the pronotum has transverse striate and is partially smooth and glossy, the posterior ⅔ has longitudinal striae; most of the striae on the dorsum of the mesonotum and propodeum are longitudinal, those on the posterior face of the propodeum are transverse, with much of the surface shining, the sides of the mesosoma have mostly longitudinal striae. The side of the petiole has poorly defined horizontal striae, which partially cover the posterior face of the petiole, at least near the apex, the top of the petiole has transverse striae and the gaster is smooth and glossy with scattered punctures.

Queen
From Mackay and Mackay (2010): The female (undescribed) is larger than the worker (total length 15 mm) black with partially brown appendages. The mandible has five well-developed teeth with four smaller teeth spaced between them. The clypeus is broadly rounded, the sides of the head converge anteriorly and the posterior border is strongly concave. The head length is 3.3 mm; the head width is 3.4 mm. The eye is moderately large (maximum diameter 0.9 mm) located less then one diameter from the anterior margin of the head (seen from the side). The scape is relatively short (2.8 mm) and does not reach the posterior lateral corner of the head. The pronotal shoulder is slightly swollen but does not form a carina. The propodeal spiracle is slit-shaped; the petiole and gaster are similar to those of the worker.

The pilosity and sculpture are similar to those of the worker.

Male
Males are not known for this species.

Type Locality Information
Colombia (without locality) and Venezuela, Puerto Cabello (apparently misspelled as Caballo) (Mackay and Mackay 2010)

Etymology
The name of this species is based on two Latin words, fuscus, meaning dark and atra, meaning black, referring to the color. (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.


 * Kempf, W. 1961. As formigas do gênero Pachycondyla Fr. Smith no Brasil (Hymenoptera: Formicidae). Revista Brasileira de Entomologia. 10:189-204.




 * Roger, J. 1861a. Die Ponera-artigen Ameisen. Berliner Entomologische Zeitschrift 5:1-54.