Oxyepoecus

Identification
Kempf (1974) - As presently defined, the genus Oxyepoecus is a small, highly homogeneous and clearly delimited group of ant species that bear a great resemblance with Solenopsis, but differ at once by the 3-segmented antennal club. In addition, the dentate propodeum and the more extensively sculptured integument of the body, especially on the thoracic pleura, separate Oxyepoecus workers and females from the same castes of nearly all Solenopsis species. The female is also distinct by her small size, scarcely exceeding that of the worker.

Distribution
In Brazil, these ants have been found in all southeastern States (Rio Grande do Sul, Santa Catarina, Paraná, São Paulo and Rio de Janeiro, their northernmost known limit being in Goiás State (Anápolis) and northeastern Minas Gerais State (Pedra Azul), at Lat. 16°S. In Bolivia, in spite of only very few records, the genus occurs as far north as Guayaramerin (olim: Puerto Sucre, opposite to the Brazilian Guajará-Mirim, Rondônia Territory) in the northern tip of the Beni province, at Lat. 11°S. In the Argentine, the collections range from the Buenos Aires Province over Córdoba to Tucumán, giving the southern limit at Lat. 36°S, and the western limit at Long. 68°W of their presently known territory. The most widespread species is actually O. inquilinus, which occurs in northwestern Argentina, northeastern Bolivia, central and southeastern Brazil. (Kempf 1974)

Additional species and distributional data from Albuquerque et al. (2004) extend the range to include Ecuador, Peru and the Brazilian states of Piauí and Amazonas.

Biology
What follows is modified from Kempf (1974), with much of what he stated then still holding true regarding the paucity of biological information for any species in this genus.

Our knowledge of Oxyepoecus ants still rests exclusively on chance discoveries. Since about 95% of the known specimens were taken as strays in berlesates of forest floor cover, very little may be said about the biology of Oxyepoecus species except for being denizens or at least foragers in this particular habitat.

Independent colonies seem to be vouched for by Oxyepoecus punctifrons and Oxyepoecus rastratus. The types of the former, collected at Rio Negro, Paraná State, Brazil, came from a nest that had over 60 workers living by themselves, but no further information is available. I have found a few workers of the same species, at Campos do Jordão, São Paulo State, Brazil, on a dead twig, between the bark and an overgrown cover consisting of lichens and mosses. The types of the var. luederwaldti (= rastratus) are from a very small colony nesting under the bark in a simple cavity within the alburnum of a tree (Luederwaldt, 1926: 275). Lenko's rastratus specimens from Caraça, Minas Gerais State, had their nest within a decaying log on the ground in a forest.

A symbiotic relationship, the nature of which is completely unknown, is indicated at least for Oxyepoecus bruchi, Oxyepoecus daguerrei and Oxyepoecus inquilinus upon the following evidence:

1. bruchi. This species was collected once or twice in nests of Pheidole obtusopilosa Mayr at Alta Gracia and La Granja, Córdoba, Argentina. Directly observed were several dealated females. Later, among alcohol material of the same Pheidole species (same colony?) the worker was also discovered (Santschi, 1926: 7, 1929: 295). The infiltration of ''Ph. obtusopilosa colonies with O. bruchi'' does not seem to be common. Kusnezov examined 21 colonies of ''Ph. obtusopilosa without finding any O. bruchi or other species of Oxyepoecus'' (Krusnezov, 1952: 718). Yet while examining three nests of Pheidole silvestrii (= Pheidole rosae) at Tafi Viejo, Tucumán, Argentina, he found in one of them several workers of an Oxyepoecus which he described as a new species under the name of O. minutus but is a straight synonym of bruchi. The infested Pheidole colony with their guests was placed in an artificial nest and kept under observation. No hostility was observed between ''Ph. silvestrii and O. minutus (= bruchi''), a fact which Kusnezov tries to explain by the great similarity between the workers of both species.

2. daguerrei. Here the evidence is very slim and rests solely upon the fact that the daguerrei workers were received by Santschi already mounted on the same pin with Solenopsis metanotalis var. picturata Santschi and S. tetracantha Emery, collected at Rosas, B. A., Argentina. The association between daguerrei and the two Solenopsis species, though possible, is only a surmise. O. daguerrei is known solely from the three type specimens.

3. inquilinus. The types and subsequent Argentine material (workers only) were invariably discovered in nests of Pheidole radoszkowskii. Yet inquilinus infestation is not common, since it was found only in 2 of 41 radoszkowskii colonies, prior to the description of the former. Placed together in the glass container of an aspirator, Pheidole radoszkowskii soldiers showed themselves very hostile toward the inquilinus workers by endeavoring to cut them up into pieces with their heavy mandibles (Kusnezov, 1952: 718). My own field experience, based on the hitherto known Brazilian material, suggests a similar relationship, inasmuch as several stray inquilinus workers (described under the name of turgidus, a straight synonym of the former species) were collected with Pheidole schwarzmaieri and Pheidole claviscapa workers swarming out of their disturbed nests, at Anápolis, Goiás State. A definite association, however, was not observed in nature (Kempf, 1969: 281).

Nomenclature

 *  OXYEPOECUS [Myrmicinae: Solenopsidini]
 * Oxyepoecus Santschi, 1926d: 6. Type-species: Oxyepoecus bruchi, by monotypy.
 * Oxyepoecus senior synonym of Forelifidis (and the junior homonym Martia Forel): Brown, 1955b: 68.
 * FORELIFIDIS [junior synonym of Oxyepoecus]
 * Forelifidis Smith, M.R. 1954a: 17. Replacement name for Martia Forel, 1907a: 20. [Junior homonym of Martia Ragonot, 1887: 18 (Lepidoptera).]
 * Forelifidis junior synonym of Oxyepoecus: Brown, 1955b: 68.

Additional References

 * [[Media:Albuquerque 2004.pdf|Albuquerque, N. L.; Brandão, C. R. F. 2004. A revision of the Neotropical Solenopsidini ant genus Oxyepoecus Santschi, 1926 (Hymenoptera: Formicidae: Myrmicinae). 1. The vezenyii species-group. Papeis Avulsos de Zoologia (Sao Paulo) 44(4): 55-80 PDF]]