Pachycondyla

Pachycondyla has been the focus of the greatest taxonomic confusion within Ponerinae, and was previously considered the senior synonym of numerous genera which are now considered distinct. Pachycondyla is in reality a small Neotropical genus (less than 20 described species) that is closely related to Dinoponera. Relatively little is known about its habits.

Identification
Schmidt and Shattuck (2014) - Pachycondyla workers are fairly generalized and lack any obvious autapomorphies, making their diagnosis more complicated than for most ponerine genera. They can most easily be identified by the following combination of characters: mandibles triangular, anterior clypeal margin without projecting teeth, metanotal groove at most present as a faint suture, propodeal spiracles slit-shaped, metapleural gland orifice with a posterior U-shaped cuticular lip, arolia not prominent, tarsal claws unarmed, petiole a thick block-like node, stridulitrum absent from pretergite of A4, and hypopygium with a row of stout spines on either side of the sting. Pachycondyla is most likely to be confused with Dinoponera, Neoponera, Ectomomyrmex, or Bothroponera, but Pachycondyla differs from Dinoponera in its smaller size, triangular mandibles, unarmed clypeal margin and tarsal claws, and block-like petiole; from Neoponera in its lack of a stridulitrum on the pretergite of A4 and by its hypopygial spines; from Ectomomyrmex in its complex metapleural gland orifice and hypopygial spines; and from Bothroponera in its hypopygial spines.

Distribution
The range of Pachycondyla extends from the southern United States (Louisiana and Texas) to northern Argentina, and includes some islands of the Caribbean (Kempf, 1961). Pachycondyla harpax covers most of the range of the genus, but most other Pachycondyla species have a much more restricted range.

Biology
Relatively little is known about the ecology and behavior of Pachycondyla. Longino (2013) reports that Pachycondyla harpax and Pachycondyla impressa forage on the forest floor and are never observed foraging arboreally. They are presumably generalist predators and scavengers, though published accounts of their food preferences are scant. Wheeler (1900b) reported that P. harpax workers in captivity would feed on egg yolk and sugar but ignored termites, Overal (1987) stated that P. harpax eats soft-bodied insects (including termites) and myriapods, and Garcia-Pérez et al. (1997) observed P. harpax preying predominantly on termites. Pachycondyla striata will readily harvest and consume fruits and the arils of seeds from the forest floor, though it is unknown if this behavior occurs in other members of the genus (Pizo & Oliveira, 1998, 2001; Passos & Oliveira, 2002, 2003, 2004; Raimundo et al., 2004). Nestmates are apparently recruited to food sources via tandem running (observed in P. harpax and P. impressa; S. Levings, pers. comm. cited in Hölldobler & Wilson, 1990).

When reported, nests are constructed in the ground (P. harpax and P. impressa; Wheeler, 1900b; Overal, 1987; Longino, 2013) or in soil collected in the crowns of palms (P. harpax; Overal, 1987). Mating occurs via typical nuptial flights (P. harpax: Longino, 2013; P. impressa: Ortius & Lechner, 1997). Wheeler (1900b) reported on egg production by workers of P. harpax, which he interpreted as being ergatoid queens but which are more likely just normal workers laying haploid eggs, as is common in Ponerinae. The mandibular, Dufour’s and venom gland secretions of P. striata were studied by Morgan et al. (1999, 2003; the mandibular gland of this species was also studied by Tomotake et al., 1992, and Mathias et al., 1995), the ovaries and corpora allata of P. striata queens and workers were compared by Thiele & Mathias (1999) and Figueira & Mathias (2002), respectively, the fat body of P. striata queens was studied by Thiele & Mathias (2003), and the structure of the venom gland in P. striata was described by Ortiz & Mathias (2003, 2006). Overal (1987) observed that P. harpax produces a foamy defensive secretion from the tip of the abdomen, similar to the behavior exhibited by Pseudoneoponera. P. harpax also injects venom from the sting, and Orivel & Déjean (2001) measured the toxicity of this species’ venom.

Karyotype
The karyotypes listed as belonging to two unidentified Pachycondyla species by Goni et al. (1982) and Imai et al. (1983), both from Malaysia, are not Pachycondyla species and their taxonomic placement is unclear.

Nomenclature

 *  PACHYCONDYLA [Ponerinae: Ponerini]
 * Pachycondyla Smith, F. 1858b: 105. Type-species: Formica crassinoda, by subsequent designation of Emery, 1901a: 42.

Description
Schmidt and Shattuck (2014):

Worker
Medium to large (TL 7–20 mm) robust ants with the standard characters of Ponerini. Mandibles triangular, sometimes with a faint basal groove. Anterior margin of clypeus convex and often medially emarginate. Frontal lobes moderately large. Eyes of moderate size and located anterior of head midline. Pronotum often with sharp lateral margins. Mesopleuron variable: fully, partially, or not at all divided by a transverse groove. Metanotal groove absent or at most present as a faint suture. Propodeum broad dorsally. Propodeal spiracles slit-shaped. Metapleural gland orifice with a posterior U-shaped cuticular lip and a lateral depression. Metatibial spur formula (1s, 1p). Petiole with a thick block-like node which widens posteriorly. Gaster with only a weak girdling constriction between pre- and postsclerites of A4. Hypopygium with a row of stout spines on either side of the sting. Head and body densely punctate to striate (rugoreticulate in at least one population of P. harpax), with abundant pilosity and dense pubescence. Color dark brown to black.

Queen
Winged, with ocelli and the other modifications typical of ponerine queens, and slightly larger than the worker, but otherwise very similar to that caste.

Male
See descriptions for individual species in Smith (1858) and Santschi (1921).

Larva
Described for individual species by Wheeler & Wheeler (1952).