Paltothyreus tarsatus

From Mackay and Mackay (2010): Pachycondyla tarsata has volatile material in the venom gland, which includes bitter-tasting cyclic dipeptides (Morgan et al., 2003). Although workers forage individually, workers transfer prey to other workers during the journey back to the nest (López et al., 2000).

Identification
From Mackay and Mackay (2010): Pachycondyla tarsata can be easily separated from all of the New World species by the angulate anterior lateral corners of the postpetiole and the presence of single small teeth on each of the inner margins of the tarsal claws. The specimen from São Paulo is nearly identical to the typical Old World Pachycondyla tarsata. It can be differentiated by the form of the surface of the medial lobe of the clypeus (which is completely concave with notable longitudinal striae in most Old World P. tarsata), smooth surface of the mandible (striate and dull in Old World P. tarsata), the transverse striae on the mesonotum (longitudinal in most Old World P. tarsata) and by the smooth and glossy dorsal surface of the gaster (smooth and glossy, but with scattered coarse punctures in most Old World specimens of P. tarsata). It is probable that this specimen of P. tarsata is a mislabeled Old World species, but it may also represent a new species.

It is interesting to note that the striae on the dorsum of the pronotum are very similar to those of Pachycondyla magnifica. The two species are apparently not closely related and easily separated by the claw on the inner border of the tarsal claw and the angles on the postpetiole of P tarsata, both of which are absent in P. magnifica.

There are currently a number of subspecies recognized (P. tarsata delagoensis [Emery], P. tarsata mediana [Santschi], P. tarsata robusta [Santschi], P. tarsata striata [Santschi], P. tarsata striatidens [Santschi] and P. tarsata subopaca [Santschi]) and possibly some of these may be recognized as valid species when the Old World fauna is evaluated.

Distribution
Africa and Brasil.

From Mackay and Mackay (2010):

"The specimen from São Paulo would be identified as P. tarsata delagoensis in Santschi’s key (1919b:81-82). It is very similar to a specimen from Mozambique (MCZC), differing in having more smooth mandibles and a more developed subpostpetiolar process.

Smith (1858:94) lists P. tarsata as being a South American species (Demerara, Pará, Brasil), which may be further support for the hypothesis that this species is found in the New World. Unfortunately Pachycondyla commutata was misidentified as P. tarsata prior to 1860 (Roger, 1860), which may also explain Smith’s report."

This taxon was described from Senegal.

Nomenclature

 *  tarsata. Formica tarsata Fabricius, 1798: 280 (w.) SENEGAL. Latreille, 1802c: 736 (q.); Mayr, 1866b: 893 (m.). Combination in Paltothyreus: Mayr, 1862: 736; in Pachycondyla: Brown, in Bolton, 1995b: 310. Senior synonym of gagates, pestilentia, spiniventris: Roger, 1860: 310; Roger, 1863b: 17; of simillima: Emery, 1892d: 557. Current subspecies: nominal plus delagoensis, kaya, mediana, robusta, striatidens (unresolved junior homonym), subopaca. See also: Forel, 1891b: 136; Arnold, 1915: 44; Wheeler, W.M. 1922a: 60; Hölldobler, 1980: 86; Mackay & Mackay, 2010: 545.
 * gagates. Ponera gagates Guérin-Méneville, 1844a: 423 (w.) SENEGAL. Junior synonym of tarsata: Roger, 1860: 310; Roger, 1863b: 17.
 * pestilentia. Ponera pestilentia Smith, F. 1858b: 92 (w.) SIERRA LEONE. Junior synonym of tarsata: Roger, 1860: 310.
 * simillima. Pachycondyla simillima Smith, F. 1858b: 105, pl. 7, fig. 17 (q.) SOUTH AFRICA. Combination in Paltothyreus: Mayr, 1886c: 358. Junior synonym of tarsata: Emery, 1892d: 557.
 * spiniventris. Ponera spiniventris Smith, F. 1858b: 92 (m.) SIERRA LEONE. Junior synonym of tarsata: Roger, 1860: 310; Roger, 1863b: 17.

Worker
From Mackay and Mackay (2010): The worker is a moderately large (total length 13 mm) dark reddish brown ant. The mandibles have approximately 18 teeth. The median portion of the clypeus is formed into a broad lobe, which overhangs the remainder of the clypeus. The surface of the lobe has two longitudinal depressions separating three distinct lobes (there are exceptions to this). The head is nearly square, with the length (including the lobe of the clypeus) being 3.1 mm, the width 3.0 mm. The eyes are relatively small (maximum diameter 0.56 mm) located slightly more than one maximum diameter from the anterior margin of the head. The scape is relatively short (2.66 mm), extending about 1½ funicular segments past the posterior lateral corner of the head. The sides of the head are slightly narrowed anteriorly, angulate posteriorly, with the medial posterior margin concave. The mesonotum and propodeum are barely separated on the dorsum of the mesosoma, but the metanotal suture is well developed on the side. The propodeal spiracle is elongated. The petiole is relatively narrow when viewed in profile with a distinctly concave anterior face and a broadly rounded convex posterior face, the faces of which form a poorly defined dorsal face. The subpetiolar process is well developed and consists of a thickened triangular lobe. The anterior upper corners of the postpetiole (first gastral tergum) are swollen and angulate. The stridulatory file is apparently absent (pretergite can not be well seen in the specimen from São Paulo, but the stridulatory file is absent in Old World specimens of P. tarsata). The dorsum of the pygidium is slightly concave. The arolia are not developed. The tarsal claws have a distinct tooth along in inner medial margin on both sides.

Erect hairs are abundant on the clypeus, especially along the anterior border, as they are on the dorsum of the head, the antennal scapes, the sides of the head, the posterior margin, the ventral surface of the head, the dorsum of the mesosoma, all surfaces of the petiole and all surfaces of the gaster; the hairs on the legs are mostly erect, or at least suberect. Appressed pubescence is sparse and noticeable only on the head and the gaster.

The mandibles are smooth and glossy with scattered punctures, the lobe of the clypeus has poorly defined longitudinal striae; the dorsum of the head has well-developed longitudinal striae, which diverge posteriorly. The dorsum of the pronotum has very coarse longitudinal striae, which pass transversely across the pronotum anteriorly and form longitudinal striae on the side the pronotum, the dorsum of the mesonotum has coarse transverse striae as does the dorsum of the propodeum, much of the side of the mesopleuron is smooth and glossy, but the upper region has fine striae, the sides of the propodeum have obliquely directed striae, the petiole is mostly smooth and glossy, but poorly defined striae are present on the sides and transverse striae are present across the dorsum of the node, the gaster is moderately smooth and glossy with scattered punctures.

Queen
From Mackay and Mackay (2010): See the discussion of the tarsata species complex.

Male
From Mackay and Mackay (2010): See the discussion of the tarsata species complex.

Type Locality Information
Senegal, Latreille; Sierra Leon; South Africa (Mackay and Mackay 2010)

Etymology
The name of this species is derived from the Greek word tarsos, referring to the sole of the foot, presumably referring to the unusual form of the tarsal claw. (Mackay and Mackay 2010)

Additional References

 * López, F., C. Agbogba and I. Ndiaye. 2000. Prey chain transfer behaviour in the African stink ant Pachycondyla tarsata Fabr. Insectes Sociaux 47:337-342.




 * Morgan, E., H. Jungnickel, S. Keegans, R. do Nascimento, J. Billen, B. Gobin and F. Ito. 2003. Comparative survey of abdominal gland secretions of the ant subfamily Ponerinae. Journal of Chemical Ecology 29:95-114.


 * Santschi, F. 1919b. Nouvelles Fourmis du Congo Belge du Musée du Congo Belge, à Tervueren. Revue Zoologique Africaine 7:79-91.


 * Smith, F. 1858. Catalogue of hymenopterous insects in the collection of the British Muséum. Part VI. Formicidae. London: British Muséum, 216 pp.