Pachycondyla constricticeps

From Mackay and Mackay (2010): The single worker was foraging on the ground. Pachycondyla striata was common in the same area.

Identification
From Mackay and Mackay (2010): Pachycondyla constricticeps is very similar to Pachycondyla striata with the mesosoma, petiole and gaster being identical. It is easily separated by the constricted region of the head posterior to the eyes (convex in P. striata), the relatively smaller eyes and the nearly straight posterior border (concave in P. striata). The constriction on the head of P. constricticeps would separate this species from all other New World species. The shape of the head resembles that of members of the genus Odontomachus, but the head is less narrowed and the mandibles are not elongated as in Odontomachus.

Distribution
ARGENTINA. (Mackay and Mackay 2010)

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina.

Habitat
The holotype was collected in a disturbed tropical rain forest.

Nomenclature

 * . Pachycondyla constricticeps Mackay & Mackay, 2010: 274, figs. 60, 247, 402, 403 (w.) ARGENTINA (Misiones).
 * Type-material: holotype worker.
 * Type-locality: Argentina: Misiones, 20 km. E Wanda, Picada Tirica, 2.i.2008, # 22750 (W. & E. Mackay).
 * Type-depository: IMLT.
 * Combination in Pachycondyla: Schmidt, C.A. & Shattuck, 2014: 155.
 * Distribution: Argentina.

Worker
The worker is a large (total length 14 mm) black ant. The head length is 2.94 mm; the head width (at the posterior edge of eye) is 2.40 mm. The head is strongly constricted posterior to the eye and the eye is relatively small (maximum diameter 0.55 mm).

The mandibles have 11 teeth with the apical tooth much larger than the others, which are approximately equal in size. The medial anterior border of the clypeus is slightly concave. The posterior border of the head is slightly convex. The pronotal shoulder is formed into a sharp carina, which slightly overhangs the side of the pronotum. The metanotal suture is barely marked. The propodeal spiracle is slit-shaped. The metasternal process is similar to that of Pachycondyla striata. The subpetiolar process consists of a broadly rounded lobe. The stridulatory file on the second pretergite is absent, the arolia between the tarsal claws are absent.

Erect hairs are abundant on the mandibles, clypeus, dorsal and ventral surfaces of the head, the sides of the head near the eyes and the posterior border of the head. Erect hairs are absent on most of the side of the head posterior to the eyes. The scape has several suberect hairs on the shaft. The dorsum of the mesosoma, legs, ventral and dorsal surfaces of the petiole and all surfaces of the gaster have erect and suberect hairs; sparse appressed pubescence is present on the dorsum of the head, dorsum of the mesosoma, anterior and dorsal faces of the petiole, appressed hair is abundant on the gaster. The mandibles are polished to finely striated. The dorsum of the head is covered with irregular striae, which diverge posteriorly; the striae on the dorsum of the pronotum are concentric anteriorly and diverging posteriorly, those on the mesonotum and anterior part of the dorsal face to the propodeum are longitudinal, those on the posterior half of the dorsal face are transverse or concentric, striae on the posterior face of the propodeum are transverse; those on the mesopleuron and side of the propodeum are mostly longitudinal. The striae on the dorsum of the petiole are very fine and mostly transverse, the striae on the side of the petiole are indistinct, the gaster is dull and very finely punctated.

Queen
Queens are not known for this species.

Male
Males are not known for this species.

Type Material
ARGENTINA, Misiones. Holotype worker

Etymology
From Latin, constrictus, meaning drawn together or contracted and caput, meaning head, characterizing how the head is constricted posterior to the eyes.

References based on Global Ant Biodiversity Informatics

 * Mackay, W.P. and E.E. MacKay. 2010. The systematics and biology of the New World ants of the genus Pachycondyla (Hymenoptera: Formicidae). Edwin Mellen Press Lewiston, NY