Oxyepoecus rastratus

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Oxyepoecus rastratus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Solenopsidini
Genus: Oxyepoecus
Species: O. rastratus
Binomial name
Oxyepoecus rastratus
(Mayr, 1887)

Oxyepoecus rastratus casent0178099 profile 1.jpg

Oxyepoecus rastratus casent0178099 dorsal 1.jpg

Specimen labels


One of the better collected species within the genus.


The exclusive character of the workers of O. rastratus in relation to other species in the group is the costulate sculpture between the frontal carinae, which reaches posteriorly the vertexal margin and laterally the compound eyes (Albuquerque and Brandão 2009).

Keys including this Species


South (Paraná and Santa Catarina states) and Southeastern Brazil (Espírito Santo, Minas Gerais, Rio de Janeiro and São Paulo states), and Paraguay.

Latitudinal Distribution Pattern

Latitudinal Range: -19.202778° to -27.818°.

Tropical South

Distribution based on Regional Taxon Lists

Neotropical Region: Argentina, Brazil (type locality), Paraguay.

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.


The material taken by Plaumann and by myself is from berlesates of leaf-mold; a colony collected by Lenko at Serra Carac;a, Minas Gerais, was nesting in a decaying log on the forest floor, in the vicinity of Hypoponera iheringi Forel and Brachymyrmex sp. (Kempf 1974).

A Paraguay collection (A. Wild) consisted of: "seven workers and one dealate queen....nest in red rotting log; wood was too hard for a full excavation; one chamber uncovered with gyne and brood. Also "samples in the dry Chaco and in the Parana forest suggests that this species may be present in a variety of biomes" (Delsinne et al. 2012).

Explore-icon.png Explore Overview of Oxyepoecus biology 
The following account is modified from Kempf (1974) and Albuquerque & Brandão (2009).

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. The minute size of Oxyepoecus, their color and cryptic habits hamper direct observation of their habits in natural conditions (especially inside shaded forest where light rarely reaches the ground).

Oxyepoecus has been considered very rare in collections, but our studies show that they are rather common in the leaf litter of most localities where recent surveys have been conducted in the Mata Atlântica (see Comments in Albuquerque & Brandão, 2004). It is interesting to note that one of these localities we recently surveyed, Cunha, São Paulo state has four Oxyepoecus species (Oxyepoecus myops, Oxyepoecus rastratus, Oxyepoecus longicephalus and Oxyepoecus rosai), three of which were found in one square meter of leaf-litter (sample 48; all but O. rosai). In Salesópolis, SP, we recorded five of the 17 known Oxyepoecus species (O. myops, Oxyepoecus punctifrons, O. rastratus, O. rosai and Oxyepoecus vezenyii). Both Cunha and Salesópolis are localities circa 1000 m above sea level, covered by pristine evergreen dense forest.

Although Oxyepoecus samples come mostly from forested localities, workers have been less frequently collected in places with more open vegetation, as open “cerrados” (savannas). Comparing the examined material of most species, one can see that the specimens mostly come from the same localities. This is because these localities we surveyed recently, extracting ants from the leaf-litter, or localities where careful collectors lived most of their lifes (Seara, SC, for instance, where F. Plaumann worked many years).

Kusnezov (1952) put forward the hypothesis that Oxyepoecus ants are inquilines of Pheidole and Solenopsis nests. Evidence exists for their being symbiotic relationships between several Oxyepoecus species and other Myrmicinae ants (details provided here). 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. A few workers of the same species, at Campos do Jordão, São Paulo State, Brazil, were also found 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 similar nesting situation was found from a more recent collection from Paraguay (col A. Wild).

The fact that Oxyepoecus workers are relatively abundant in material extracted from leaf litter samples, while dealate gynes are seldom found in the litter and larvae have never been found in litter samples, suggests that they nest in the soil, where the gynes and larvae live, but workers leave the nest periodically to search for food. Oxyepoecus has been attracted to honey or sardine baits set over the ground in different habitats, which suggests they are generalist foragers. In just one case, a gyne and two workers of O. punctifrons (Vezenyii group) were found by Rogerio R. da Silva under the bark of a the canopy branch in a recently fallen Leguminoseae (Albuquerque & Brandão, 2004).



Images from AntWeb

Oxyepoecus rastratus casent0178854 head 1.jpgOxyepoecus rastratus casent0178854 profile 1.jpgOxyepoecus rastratus casent0178854 dorsal 1.jpgOxyepoecus rastratus casent0178854 label 1.jpg
Worker. Specimen code casent0178854. Photographer April Nobile, uploaded by California Academy of Sciences. Owned by CAS, San Francisco, CA, USA.


Images from AntWeb

Oxyepoecus rastratus casent0178100 head 1.jpgOxyepoecus rastratus casent0178100 profile 1.jpgOxyepoecus rastratus casent0178100 dorsal 1.jpgOxyepoecus rastratus casent0178100 label 1.jpg
Queen (alate/dealate). Specimen code casent0178100. Photographer April Nobile, uploaded by California Academy of Sciences. Owned by ALWC, Alex L. Wild Collection.


The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

  • rastratus. Monomorium rastratum Mayr, 1887: 615 (w.) BRAZIL. Kempf, 1974b: 498 (q.m.); Wheeler, G.C. & Wheeler, J. 1980: 534 (l.). Combination in Monomorium (Martia): Forel, 1912g: 3; in Martia: Kusnezov, 1952h: 722; in Oxyepoecus: Ettershank, 1966: 146. Senior synonym of luederwaldti: Kempf, 1974b: 498. See also: Albuquerque & Brandão, 2009: 299.
  • luederwaldti. Monomorium (Martia) rastratum var. luederwaldti Forel, 1913l: 219 (w.) BRAZIL. Combination in Martia: Kusnezov, 1952h: 722; in Oxyepoecus: Ettershank, 1966: 146. Junior synonym of rastratus: Kempf, 1974b: 498.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Kempf 1974 oxyepoecus fig. 1-10.jpg

Kempf (1974) - There are only two known species in the genus that share with rastratus the entirely sculptured cephalic dorsum (sculpture attaining laterally the eye and posteriorly the occiput), viz. Oxyepoecus mandibularis and Oxyepoecus reticulatus.

Workers of rastratus differ from those of mandibularis in smaller size, absence of a narrow and deep cleft between the basal and subbasal tooth of mandibles, shorter antennal scapes that decidedly fall short of reaching the occipital corner when in repose, smaller and less bulging eyes, regular and densely costulate sculpture of head and promesonotum, well developed propodeal armature, broadly expanded and antero-posteriorly compressed nodes of petiole and postpetiole.

The characters that separate rastratus workers from the same caste of reticulatus are the following: sculpture of head and promesonotum consisting of regular and dense costulae, with the punctulae either absent or feebly developed; eyes larger, with 7-9 facets in a row across the greatest diameter and over 20 ommatidia in all; antennal scape a trifle longer, its apex removed from the occipital corner by just its own maximum thickness; laterotergite of pronotum smooth and shining; basal face of propodeum sharply and densely transversely costulate; propodeal teeth well developed and protruding; petiolar node scalelike, antero-posteriorly compressed and expanded laterad. In the female caste, more or less the same differences do apply, the queen of rastratus being distinct from that of reticulatus by the head sculpture, larger eyes, smooth and shining laterotergite of pronotum, densely cross-costulate basal face of propodeum, the laterally expanded and antero-posteriorly compressed petiolar node, the absence of short, curved hairs on gaster, and the presence of well-developed wings.



Kempf 1974 Oxyepoecus fig 11-22.jpg

Kempf (1974) - Total length 2.2-2.8 mm; head length 0.52-0.65 mm; head width 0.43-0.55 mm; scape length 0.30-0.40 mm; maximum diameter of eyes 0.09-0.13 mm; Weber's length of thorax 0.60-0.80 mm; maximum width of pronotum 0.32-0.40 mm; hind femur length 0.36-0.48 mm; petiole width 0.18-0.25 mm; postpetiole width 0.21-0.32 mm; cephalic index 76-84. Color reddish yellow to chestnut brown; mandibles, antennae, legs and tip of gaster always lighter; in darker specimens the gaster is usually infuscated. Integument smooth and shining with the ensuing exceptions: dorsum of head capsule with the exclusion of the smooth median apron of clypeus very finely and densely striato-costulate, the sculpture very regular with a silky sheen, due to minute punctulae between the costulae which attain laterally the eyes and posteriorly the occiput; dorsum of pronotum and mesonotum regularly, densely, longitudinally costulate, the interstices practically without punctulae; hence the integument appears shining, especially anteriorly on pronotum where often the costulae become very superficial or fade out completely, being visible only in certain lights and angles; basal face of propodeum densely, finely, transversely costulate, with about 20 costulae; mesopleura, metapleura and sides of propodeum mostly horizontally, the latter obliquely, costulate; a few (1-2) transverse, very faint costulae on top of declivous face of propodeum; peduncle of petiole finely and superficially punctulate above and on sides; posterior surface of postpetiole practically lacking transverse costulae or rugae. Hairs abundant, standing on dorsum of head, thorax, petiolar and postpetiolar nodes, and on gaster; on head, also more numerous and shorter hairs inclined mesad on disc and forward on sides; gaster practically without short, inclined hairs; antennae and legs with abundant, short, oblique to subdecumbent hairs.

Head. Mandibles short, subtriangular; between basal and subbasal tooth a deep yet broad incision. Posteriorly converging clypeal carinae and anterior teeth well developed, the lateral denticles subobtuse and lobelike. Frontal carinae short, subparallel, terminating at level of anterior orbit of eyes, the distance between their outer edges distinctly less than one third of head width. Eyes intermediate, feebly convex, with 7-9 facets in a row across the greatest diameter which is subequal to the distance between the anterior orbit and the mandibular insertion, total number of ommatidia well over 20. Antennal scape failing to reach occipital corner when laid back over the head by a distance that equals its maximum thickness. Funicular segment I equal to sum of II-V; segments II-VII broader than long, VIII and IX as long as broad.

Thorax. Shoulders faintly marked. Pronotum immarginate on sides of dorsal surface. Metanotal groove very faintly impressed, metanotal suture distinct. Basal face of propodeum immarginate laterally, its posterior corners with strong teeth, the tips of which point obliquely upward; the distance between the tips of the propodeal teeth less than maximum width of petiolar node. Lateral boriers of declivous face sharply marginate and faintly carinate.

Petiole and postpetiole. The former strongly pedunculate, with the subpetiolar process in the form of a small tooth; node antero-posteriorly compressed and scalelike, laterally expanded. Postpetiole much broader than long, somewhat compressed antero-posteriorly, the sides drawn out into bulky lobes. Gaster faintly excised at postpetiolar insertion.


Kempf (1974) - (undescribed). Total length 2.7-3.2 mm; head length 0.60-0.67 mm; head width 0.51-0.56 mm; scape length 0.37-0.41 mm; maximum diameter of eyes 0.13-0.18 mm; Weber's length of thorax 0.80-0.91 mm; maximum width of pronotum 0.43-0.52 mm; hind femur length 0.45-0.53 mm; fore wing length 2.6 mm; hind wing length 1.7 mm; petiole width 0.24 mm; postpetiole width 0.29-0.32 mm. Similar to the

Kempf 1974 Oxyepoecus fig 38-42.jpg

worker with the usual differences of the caste. Eyes larger, the maximum diameter with 11-13 facets in a row exceeds the distance between the anterior orbit and the mandibular insertion; the total number of ommatidia from 60 to 100. Ocelli small, their diameter equal to thinnest cross-section of the antennal scape. Pronotum with marked yet not tuberculate shoulders, entirely declivous in the middle, dorso-laterally obliquely, densely striato-costate. Mesonotal scutum and scutellum finely, densely and regularly longitudinally costulate. Basal face of propodeum transversely costulate, with about 16 costae; sides immarginate; propodeal teeth stout and prominent. Laterotergite of pronotum smooth and shining. Posterior third of mesopleura, the metapleura and sides of propodeum horizontally to obliquely costulate. Wings only slightly infuscated, venation as usual in the genus. The only winged specimen seen has a small discoidal cell, and an extra-vein arising from the junction of r-m with Rs and extending apicad between Rs and M, as shown in the wing of the male.


Kempf (1974) - (undescribed). Total length 2.9 mm; head length 0.51 mm; head width (eyes included) 0.60 mm; scape length 0.12 mm; maximum diameter of eyes 0.24 mm; Weber's length of thorax 0.93 mm; maximum width of pronotum 0.60 mm; hind femur length 0.58 mm; fore wing length 2.3 mm; hind wing length 1.5 mm; petiole width 0.19 mm; postpetiole width 0.24 mm. Color fuscous brown; mandibles, antennae, apical half of tibiae, tarsomeres, tip of gaster much lighter, testaceous.

Head. Mandibles with 4 well developed teeth. Clypeus transversely strongly convex, little protruding anteriorly. Frontal carinae absent. Integument finely yet sharply reticulate-punctate, opaque. Sides of pronotum and mesopleura smooth and shining, the latter vestigially costulate on posterior border. Metapleura and sides of propodeum horizontally costulate. Mesonotal scutum nearly smooth and somewhat shining, indistinctly sculptured. Scutellum superficially, finely, longitudinally costulate-striate. Basal face of propodeum superficially reticulate-rugose, the posterior corners bluntly tuberculate, not dentate. Declivous face superficially reticulate-rugose, quite shining. Petiole, postpetiole and gaster smooth and shining. Legs, especially tibiae and tarsomeres, as well as antennae sharply punctured and opaque.


  • Albuquerque, N. L. d. and C. R. F. Brandão. 2009. A revision of the Neotropical Solenopsidini ant genus Oxyepoecus Santschi, 1926 (Hymenoptera: Formicidae: Myrmicinae): 2. Final. Key for species and revision of the Rastratus species-group. Papéis Avulsos de Zoologia (São Paulo). 49:289-309.
  • 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
  • Ettershank, G. 1966. A generic revision of the world Myrmicinae related to Solenopsis and Pheidologeton (Hymenoptera: Formicidae). Aust. J. Zool. 14: 73-171 (page 146, Combination in Oxyepoecus)
  • Forel, A. 1912h. Formicides néotropiques. Part IV. 3me sous-famille Myrmicinae Lep. (suite). Mém. Soc. Entomol. Belg. 20: 1-32 (page 3, Combination in Monomorium (Martia))
  • Kempf, W. W. 1974b. A review of the Neotropical ant genus Oxyepoecus Santschi (Hymenoptera: Formicidae). Stud. Entomol. 17: 471-512 (page 498, queen, male described, Senior synonym of luederwaldti)
  • Kusnezov, N. 1952k [1951]. Acerca de las hormigas simbióticas del género Martia Forel (Hymenoptera, Formicidae). Acta Zool. Lilloana 10: 717-722 (page 722, Combination in Martia)
  • Mayr, G. 1887. Südamerikanische Formiciden. Verh. K-K. Zool.-Bot. Ges. Wien 37: 511-632 (page 615, worker described)
  • Wheeler, G. C.; Wheeler, J. 1980. Supplementary studies on ant larvae: Ponerinae, Myrmicinae and Formicinae. Trans. Am. Entomol. Soc. 106: 527-545 (page 534, larva described)

References based on Global Ant Biodiversity Informatics

  • Albuquerque, N.L. and C.R.F. Brandao. 2009. A revision of the Neotropical Solenopsidini ant genus Oxyepoecus Santschi, 1926 (Hymenoptera: Formicidae: Myrmicinae): 2. Final. Key for species and revision of the Rastratus species-group. Papéis Avulsos de Zoologia (São Paulo) 49(23): 289-309.
  • Favretto M. A., E. Bortolon dos Santos, and C. J. Geuster. 2013. Entomofauna from West of Santa Catarina State, South of Brazil. EntomoBrasilis 6 (1): 42-63.
  • Forel A. 1913. Fourmis d'Argentine, du Brésil, du Guatémala & de Cuba reçues de M. M. Bruch, Prof. v. Ihering, Mlle Baez, M. Peper et M. Rovereto. Bulletin de la Société Vaudoise des Sciences Naturelles. 49: 203-250.
  • Kempf W. W. 1974. A review of the Neotropical ant genus Oxyepoecus Santschi (Hymenoptera: Formicidae). Studia Entomologica 17: 471-512.
  • Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
  • Kusnezov N. 1952. Acerca de las hormigas simbióticas del género Martia Forel (Hymenoptera, Formicidae). Acta Zoologica Lilloana 10: 717-722.
  • Luederwaldt H. 1918. Notas myrmecologicas. Rev. Mus. Paul. 10: 29-64.
  • Morini M. S. de C., C. de B. Munhae, R. Leung, D. F. Candiani, and J. C. Voltolini. 2007. Comunidades de formigas (Hymenoptera, Formicidae) em fragmentos de Mata Atlântica situados em áreas urbanizadas. Iheringia, Sér. Zool., Porto Alegre, 97(3): 246-252.
  • Pacheco, R., R.R. Silva, M.S. de C. Morini, C.R.F. Brandao. 2009. A Comparison of the Leaf-Litter Ant Fauna in a Secondary Atlantic Forest with an Adjacent Pine Plantation in Southeastern Brazil. Neotropical Entomology 38(1):055-065
  • Rosa da Silva R. 1999. Formigas (Hymenoptera: Formicidae) do oeste de Santa Catarina: historico das coletas e lista atualizada das especies do Estado de Santa Catarina. Biotemas 12(2): 75-100.
  • Silva R. R., R. S. Machado Feitosa, and F. Eberhardt. 2007. Reduced ant diversity along a habitat regeneration gradient in the southern Brazilian Atlantic Forest. Forest Ecology and Management 240: 61-69.
  • Silva R.R., and C. R. F. Brandao. 2014. Ecosystem-Wide Morphological Structure of Leaf-Litter Ant Communities along a Tropical Latitudinal Gradient. PLoSONE 9(3): e93049. doi:10.1371/journal.pone.0093049
  • Suguituru S. S., D. R. de Souza, C. de Bortoli Munhae, R. Pacheco, and M. S. de Castro Morini. 2011. Diversidade e riqueza de formigas (Hymenoptera: Formicidae) em remanescentes de Mata Atlântica na Bacia Hidrográfica do Alto Tietê, SP. Biota Neotrop. 13(2): 141-152.
  • Suguituru S. S., M. Santina de Castro Morini, R. M. Feitosa, and R. Rosa da Silva. 2015. Formigas do Alto Tiete. Canal 6 Editora 458 pages
  • Ulyssea M. A., C. R. F. Brandao. 2013. Catalogue of Dacetini and Solenopsidini ant type specimens (Hymenoptera, Formicidae, Myrmicinae) deposited in the Museu de Zoologia da Universidade de Sao Paulo, Brazil. Papies Avulsos de Zoologia 53(14): 187-209.
  • Ulyssea M.A., C. E. Cereto, F. B. Rosumek, R. R. Silva, and B. C. Lopes. 2011. Updated list of ant species (Hymenoptera, Formicidae) recorded in Santa Catarina State, southern Brazil, with a discussion of research advances and priorities. Revista Brasileira de Entomologia 55(4): 603-–611.
  • da Silva, R.R. and R. Silvestre. 2004. Riqueza da fauna de formigas (Hymenoptera: Formicidae) que habita as camadas superficiais do solo em Seara, Santa Catarina. Papéis Avulsos de Zoologia (São Paulo) 44(1): 1-11