Oxyepoecus vezenyii

A typical Oxyepoecus ant; rarely collected and little is known about its biology.

Identification
Workers of O. vezenyii are diagnosed by a combination of characters: the elongate mandible; the relatively small eyes with circa 20 ommatidia, and the pattern of microsculpture between the frontal carinae. The gyne runs near those of O. bruchi in Kempf ’s (1974) key, however it is differentiated by the pronotum, which is not declivous in the middle, and by the relatively small mesonotum (Albuquerque and Brandão 2004).

Distribution
Known from Brazil and Paraguay.

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil, Paraguay.

Biology
Besides knowing this species has been collected in a number of ecosystems and biomes, little is known about its biology.

Castes
Males have not been collected.

Nomenclature

 *  vezenyii. Monomorium (Martia) vezenyii Forel, 1907a: 20 (w.) PARAGUAY. Kempf, 1969: 277 (q.). Combination in Martia: Kusnezov, 1952h: 722; in Oxyepoecus: Ettershank, 1966: 145. See also: Kempf, 1974b: 505.

Kempf (1974) - The closest relative of vezenyii, on account of the long, linear mandibles, the smooth integument and the antero-posteriorly compressed petiolar and postpetiolar nodes, is Oxyepoecus inquilinus, from which the worker of the former differs as follows: eyes much smaller, with only 6-7 facets across the greatest diameter which is inferior to the distance that separates the eye from the mandibular insertion, the total number of ommatidia not surpassing 20-25 in all; pronotum submarginate in front and on the sides, shoulders distinctly marked and subdentate; frontal carinae more approximated to each other, the maximum distance between their outer edges distinctly less than one third of head width; costulate-striate sculpture, although in part very faint and only vestigial, more extensive on frons and on sides of thorax; subpetiolar tooth with a foliaceous appendix.

The female, although conspicuously ergatomorphic on account of the poor development of the eyes, the ocelli and the pterothorax, and the total absence of wings, is nevertheless close to Oxyepoecus bruchi from which it has already been separated on a foregoing page.

Worker
Kempf (1974) - Total length 2.4-3.0 mm; head length 0.57-0.67 mm; head width 0.47-0.55 mm; scape length 0.36-0.41 mm; maximum diameter of eyes 0.08-0.09 mm; Weber's length of thorax 0.68-0.79 mm; maximum width of pronotum 0.36-0.44 mm; hind femur length 0.39-0.47 mm; petiole width 0.23-0.31 mm; postpetiole width 0.27-0.35 mm; cephalic index 79-84. Color light ferruginous; mandibles, antennae and legs lighter, more yellowish, gaster usually somewhat infuscated. Integument smooth and shining with the following exceptions: frontal carinae longitudinally costulate, the costulae prolonged caudad and obliquely laterad, reaching beyond level of posterior orbit of eyes where they become faint to vestigial; cheeks with a few longitudinal rugae that reach the anterior orbit of eyes; postero-lateral corner of dorsal disc of pronotum, sides and posterior third of mesonotum, mesopleura, metapleura and sides of propodeum with longitudinal costulae, which especially on pronotum, mesonotum and mesopleura vary in their degree of distinctness, from vestigial to well formed; basal face of propodeum with 10-15 costulae, 6-8 strong ones, the others weak; sides of petiolar node with a few, widely spaced horizontal rugulae; posterior surface of postpetiole with several rows of indistinct to well-expressed transverse rugae. Hairs abundant, long, standing on head, dorsum of thorax, petiole and postpetiole, and on gaster; on head, besides the scarcer standing hairs are inclined and shorter ones, inclined mesad dorsally on disc, forward on sides; gaster without these interspersed shorter and inclined hairs.

Head. Mandibles rather elongate than subtriangular, with a broad and relatively shallow diastema between the basal and subbasal tooth. Median apron of clypeus projecting above mandibles, with the usual posterior converging carinae and the anterior teeth; the lateral denticles blunt, lobe-like. Frontal carinae gently convex, slightly constricted posteriorly, the maximum width between their outer edges always less than one third of head width. Frontal area impressed, smooth and shining, ill-delimited. Eyes relatively small, with about 6-7 facets in a row across the greatest diameter which is less than the distance between the anterior orbit and the mandibular insertion: total number of ommatidia about 20. Antennal scapes failing to reach the occipital corner by a distance equalling the maximum thickness of the scape. Funicular segment I as long as II-V combined, segments II-VII distinctly broader than long, VIII and IX as long as broad.

Thorax. Shoulders marked, somewhat tuberculate, sides of pronotum submarginate. Metanotal groove shallowly impressed, metanotal suture indistinct. Basal face of propodeum immarginate on sides, posteriorly with two small, pointed denticles. Declivous face laterally marginate and weakly carinate.

Petiole and postpetiole; the former strongly pedunculate, subpetiolar process elaborate and foliaceous, node strongly compressed antero-posteriorly and laterally expanded in a scalelike fashion, nearly as broad as postpetiole. The latter unusually broadened due to the drawn out lateral bulky lobes. Gaster shallowly excised at the postpetiolar insertion.

Queen
Kempf (1974) - (ergatomorphic). Total length 3.1 mm; head length 0.64 mm; head width 0.53 mm; scape length 0.43 mm; maximum diameter of eyes 0.11 mm; Weber's length of thorax 0.84 mm; maximum width of pronotum 0.43 mm; hind femur length 0.46 mm; petiole width 0.30 mm; postpetiole width 0.35 mm; cephalic index 82. Resembling the worker with the modification proper of the caste. Eyes surprisingly small, as in worker, with less than 30 ommatidia. Ocelli minute, their diameter less than the minimum thickness of scape. Thorax with bluntly marked shoulders, pronotum not entirely declivous in the middle, nearly one third of the maximum length is horizontal along the sagittal line, on anterior corners a few faint transverse to oblique rugae, the rest smooth and shining. Mesonotum (scutum and scutellum) relatively small, their combined length subequal to one half of Weber's length of thorax; scutum smooth and shining with heavier piligerous punctulae; scutellum entirely smooth. Basal face of propodeum transversely costate, with 8-10 costae, which continue downward and obliquely forward on the sides. Mesopleura smooth and shining. Propodeal spines short but pointed. Petiole and postpetiole as in worker, the subpetiolar process in the form of a small foliaceous lobe. Wings never developed.

Type Material
Kempf (1974) - The lone holotype in the Forel collection was not seen during this study.

Additional References

 * Albuquerque, N. L. d. and C. R. F. Brandão. 2004. A revision of the Neotropical Solenopsidini ant genus Oxyepoecus Santschi, 1926 (Hymenoptera: Formicidae: Myrmicinae). 1. The Vezenyii species-group. Papéis Avulsos de Zoologia (São Paulo). 44:55-80. DOI: 10.1590/S0031-10492004000400001


 * Delsinne, T., W. Mackay, A. Wild, Y. Roisin, and M. Leponce. 2012. Distribution and Diversity of the Cryptic Ant Genus Oxyepoecus (Hymenoptera: Formicidae: Myrmicinae) in Paraguay with Descriptions of Two New Species. Psyche. 2012. DOI:10.1155/2012/594302