Pachycondyla crassinoda

From Mackay and Mackay (2010): This species nests under rotten logs or in damaged parts of trees. Alate females were collected in May (Ecuador), July (Venezuela and Perú), in a pitfall trap in October (Venezuela) and December (Ecuador). Dealate females were collected loose in April, May, July to September (Ecuador) and September (Perú). Males were collected in June (Perú), August and September (Ecuador). One colony was collected in a nest of the army ant Eciton rapax. Workers can be found foraging in the rain forest and on leaf litter at the edge of the forest. These ants are opportunist predators on termites in the genera Cornitermes, Labiotermes and Syntermes  (Mill, 1982a). Some workers were collected in a dung (human) baited pitfall trap. The pupae of this species are parasitized by the eucharid wasp Kapala cuprea (Myers, 1931:276).

Identification
From Mackay and Mackay (2010): The large size and the two large teeth at the sides of the apex of the gaster would separate both the workers and the females of  P. crassinoda from all other species in the New World. These processes can be easily seen with the naked eye. Pachycondyla impressa is very similar with the concave upper surface of the pygidium, but lacks the two lateral angulate processes (a raised area with coarse short hairs may be present on the lateral margins).

Distribution
Northern through central South America, Trinidad, British West Indies. (Mackay and Mackay 2010)

This taxon was described from Surinam.

Habitat
Pachycondyla crassinoda is a common species found in tropical rain forest, seasonal rain forest, secondary tropical forest, a forest ravine, tierra firme forest and gallery forest, often at gap edges, at elevations between 200 - 750 meters. (Mackay and Mackay 2010)

Nomenclature

 *  crassinoda. Formica crassinoda Latreille, 1802c: 198, pl. 7, fig. 41 (w.q.) SURINAM. Wheeler, G.C. & Wheeler, J. 1952c: 617 (l.); Mackay & Mackay, 2010: 284 (putative m.). Combination in Pachycondyla: Smith, F. 1858b: 105. See also: Mackay & Mackay, 2010: 282.

Worker
From Mackay and Mackay (2010): The worker of this species is easily recognized as being the largest species in the New World (total length nearly 20 millimeters). The shape of the pygidium (dorsum of the end of the gaster) is unusual in that it terminates in two lateral blunt processes and a medial process, which covers the dorsum of the sting. The region between the two lateral processes is concave. The sides of the pygidium are covered with longitudinal striae. The form of the pygidium can be easily recognized in the field with the naked eye. Other characters of this species include the clypeus being concave medially and convex laterally. The malar carina is absent. The eye is located anteriorly on the head about one diameter from the anterior edge of the head (side view) and the scape barely extends past the posterior lateral corner. The pronotal shoulder is swollen, but does not form a carina; the mesosoma is not depressed at the metanotal suture, which barely interrupts the sculpture on the dorsum. The propodeal spiracle is elongated. The petiole is rectangular-shaped and often slightly wider near the apex as compared to near the base (as seen from the side). There is a definite dorsal surface, which is separated from the anterior and posterior faces by approximately right angles. The anterior face of the postpetiole is nearly vertical and forms a right angle with the dorsal surface. Erect hairs are abundant on most surfaces including the dorsum and ventral surfaces of the head, the scapes, the dorsum of the mesosoma, the dorsum of the petiole and all surfaces of the gaster, the hairs on the tibiae are suberect, all hairs are golden yellow in color, contrasting with the black background color of the integument. Appressed pubescence is also present and golden yellow in color and is especially abundant on the dorsum of the head, dorsum of the mesosoma, dorsum of the petiole and dorsum of the gaster.

Nearly all surfaces are densely but finely punctate and dull or weakly shining, the mandibles are polished with scattered punctures, the posterior face of the petiole is glossy and shining, the anterior face of the postpetiole is finely sculptured, but not as glossy and shining as the petiole. This ant is nearly completely black, the mandibles are dark reddish brown and the tarsi are slightly lighter in color.

Queen
From Mackay and Mackay (2010): The female is similar to the worker, except the mesosoma is more massive. The total length is about 23 mm. The anterior border of the clypeus is broadly convex with a concave medial area. The malar carina is absent; the eyes are large (maximum diameter 0.94 mm). The scape extends slightly past the posterior lateral corner of the head. The pronotal shoulder is swollen, but does not form a carina. The propodeal spiracle is elongated. The petiole is thick and rectangular when viewed in profile, similar in shape to that of the worker. The pygidium forms a concave dorsal face with two well-developed lateral sharp processes.

Long (up to 1 mm) erect and suberect hairs are present on the mandibles, clypeus, dorsal and ventral surfaces of the head, posterior margin, scapes, dorsum of the mesosoma, dorsum of the petiole, subpetiolar process and gaster, the hairs on the legs are mostly suberect. Appressed golden fine pubescence is present on essentially all surfaces.

The mandibles are covered with coarse punctures and very fine striae, but are mostly dull, the remainder of the head is covered with very fine dense punctures, the mesosoma is covered by a combination of fine punctures mostly arranged in rows (transverse on the pronotum, longitudinal on the scutum, transverse on the scutellum and propodeum), the sides of the mesosoma are covered with a mixture of punctures and striae. The anterior face of the petiole is punctate and moderately shining, the dorsum and sides are covered with fine punctures, the posterior face is coriaceous and moderately shining, the gaster is punctate and weakly shining. The ant is predominantly black with dark reddish brown mandibles.

Male
From Mackay and Mackay (2010): (identification questionable)

The male is a large (total length 15 mm) black specimen. The mandibles are tiny but have a well-developed depression at the base. The anterior margin of the clypeus is broadly concave and is not strongly swollen when viewed from side. The head length is 2.10 mm; the head width is 2.04 mm. The eye (maximum diameter viewed from side 1.02 mm) is located about ⅔ of the diameter from the lateral ocellus. The median ocellus (maximum diameter 0.23 mm) is located slightly more than 1 diameter from the lateral ocellus (maximum diameter 0.23 mm). The pronotal shoulder is slightly swollen but does not form a carina. The propodeal spiracle is slit-shaped. The petiole as wide (1.44 mm from above the anterior peduncle to above the posterior peduncle); the spiracular horn is developed into an angle; the spiracle is small. The apex of the node is broadly rounded. The subpetiolar process consists of a rounded angle anteriorly and a smaller angle posteriorly with the region between them distinctly concave. The subpostpetiolar process is poorly developed. The wing venation is similar to that of Pachycondyla lattkei. The pygidium lacks the two lateral teeth which are found in the female and a worker.

Erect hairs are abundant but fine and flexuous on all surfaces except the legs where they are very fine on the femora and nearly absent on the tibiae. Most surfaces are covered with a golden pubescence which is appressed to slightly raised from the surface.

The surface of the clypeus is distinctly punctate; the remainder of the head is very finely punctate with small punctures. The dorsum and sides of the mesosoma are mostly finely punctate, the sides of the pronotum, mesopleuron and lower half of the propodeum are moderately shining and mostly without any evidence of rugae, except for the area above and anterior to the propodeal spiracle. The petiole is completely and coarsely rugose with the areas between the rugae being shining. The gaster is finely punctate and weakly shining. This male was not associated with workers, but may be P. crassinoda based on the relatively wide petiolar node and the concave subpetiolar process, which is also concave in the females and workers, although less so. A process of elimination suggests it is apparently not the male of any other species of the crassinoda species complex found in Perú. The male can be separated from the very similar male of P. lattkei as it nearly lacks all of the rugose sculpturing on the side of the propodeum, which is present in P. lattkei. The rugae on the side of the petiole would separate it from that of Pachycondyla impressa.

Type Locality Information
French Guiana: Cayenne (Mackay and Mackay 2010)

Etymology
The name of this species is derived from two Latin words: crassus, meaning thick and nodus, meaning swelling, referring to the thick petiolar node of the worker and female of this species. (Mackay and Mackay 2010)

Additional References

 * Latreille, P. A. 1802. Histoire Naturelle des Fourmis, et recueil de mémoires et d’observations sur les abeilles, les araignées, les faucheurs, et autres insectes. Paris, 445 pp.




 * Mill, A. E. 1982a. Faunal studies on termites (Isoptera) and observations on their ant predators (Hymenoptera: Formicidae) in the Amazon Basin. Revista brasilera de Entomologia 26:253-260.


 * Myers, J. G. 1931. Descriptions and records of parasitic Hymenoptera from British Guiana and the West Indies. Bulletin of Entomological Research 22:267-277.