Oxyepoecus myops

Oxyepoecus myops
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Solenopsidini
Genus:	Oxyepoecus
Species:	O. myops
Binomial name
	Oxyepoecus myops; Albuquerque & Brandão, 2009 Specimen Labels

Workers of this species have been recently extracted from litter samples taken in localities at sea level and up to more than 1000 m high in the Serra do Mar Range. Most localities are covered by dense evergreen tropical forests, but in some cases, samples come from drier forests as well, as in Seara, SC and Teresópolis, RJ. In Serra da Cantareira, SP, workers were attracted to sardine baits set on the forest floor during the day.

Identification

Albuquerque & Brandão (2009) - The exclusive character of Oxyepoecus myops workers in relation to the other species of the Rastratus group is the irregularly reticulate sculpture fully covering the head dorsum and almost all the mesosoma dorsum. Their compound eyes are the smallest in the genus.

Keys including this Species

Key to Oxyepoecus species

Distribution

The distribution of O. myops includes several Southern Brazil localities, and in Minas Gerais, São Paulo and Rio de Janeiro States.

Latitudinal Distribution Pattern

Latitudinal Range: -14.80805556° to -27.817°.


North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

Source: AntMaps

Distribution based on Regional Taxon Lists

Neotropical Region: Brazil (type locality).

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.

Biology

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).

Castes

Males are unknown.

Nomenclature

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

myops. Oxyepoecus myops Albuquerque & Brandão, 2009: 295, figs. 1a-c, 6 (w.q.) BRAZIL.

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

Description

Worker

(Holotype and paratypes (N = 30), variation within brackets): t.l. = 2.08 (1.95‑2,15); h.l. = 0.53 (0.50‑0.53); h.w. = 0.40 (0.38‑0.43); s.l. = 0.30 (0.28‑0.31); m.l.e. = 0.06 (0.05‑0.08); m.w.pr. = 0.25 (0.23‑0.28); a.l. = 0.60 (0.58‑0.60); h.f.l. = 0.33 (0.28‑0.33); m.w.p. = 0.15 (0.13‑0.18); m.w.pp. = 0.20 (0.18‑0.20); c.i. 75 (76‑81). Color chestnut brown, legs and antennae slightly lighter. Integument with irregularly reticulate sculpture covering almost all head dorsum, except close to clypeus, and around antennal insertions; almost all mesosoma, petiole dorsum and postpetiole with irregulary reticulate sculpture; gaster smooth and shining. Hairs relatively abundant, short, subdecumbent and curved mesad on head dorsum, and anteriorly curved on the head sides; long and suberect on dorsum of mesosoma, petiole and postpetiole; hairs on gaster decumbent and shorter.

Mandible with basal border approximately equal chewing border, basal tooth separated from subbasal tooth by shallow diastema. Anterior tooth of clypeus with lateral, blunt denticle. Frontal carinae short, subparallel, with posterior end at level of anterior margin of compound eye, maximum width between their outer edges less than one fourth of head width. Compound eye very small, with 3‑4 facets r.g.d.; total number of ommatidia not exceeding 7. Antennal scape fails to reach vertexal margin by distance greater than maximum scape width. Funnicular segment I longer than either VIII or IX, as long as II‑V combined, segments II‑VII distinctly broader than long, VIII and IX as long as broad. Head with vertexal margin straight (f.f.v.).

Mesosoma with lateral and dorsal surfaces of pronotum not forming a well marked angle, slightly rounded. Metanotal groove weakly impressed (p.v.). Basal face of propodeum immarginate on sides, posteriorly with a small and obliquely directed tooth (p.v.). Declivous face laterally weakly carinate.

Petiole pedunculate, node scarcely compressed antero-posteriorly (d.v.); subpetiolar process with anterior end as a small and obliquely oriented denticle. Postpetiole strongly compressed antero-posteriorly, not as high as petiolar node; subpostpetiolar process shaped as small, transversal crest, parallel to ventrally produced posterior socket of postpetiole.

Queen

(variation of three paratype gynes): t.l. = (2.53‑2.58); h.l. = (0.55‑0.56); h.w. = (0.45‑0.48); s.l. = (0.33‑0.35); m.l.e. = (0.20‑0.25); m.w.pr. = (0.43‑0.45); a.l. = (0.70‑0.73); h.f.l. = (0.38‑0.40); m.w.p. = (0.18‑0.20); m.w.pp. = (0.28‑0.30); c.i. (81‑86). Characters almost the same as workers, with the differences of the caste: the three ocelli with same diameter, approximately equal to minimum scape width, compound eye with 10 facets r.g.d., about 30 in all, scutellum not marginate.

Type Material

Holotype: worker. Brazil: São Paulo: Salesópolis [23°39’S, 45°53’W], 05‑07.vii.1997, C.I. Yamamoto col., extracted from the leaf litter using Winkler extractor; deposited in Museu de Zoologia da Universidade de Sao Paulo. Paratypes (all from Brazil): São Paulo: thirty workers and three gynes from Salesópolis (same locality of the Holotype, but collected in different dates and by different collectors), deposited in MZSP, one worker deposited in American Museum of Natural History, one worker deposited in California Academy of Sciences, one worker deposited in Instituto de Biologia Universidade Federal Rural do Rio de Janeiro, one worker deposited in Laboratório de Mirmecologia CEPEC / CPDC, one worker deposited in Museo de Historia Natural, Bogata, one worker deposited in Los Angeles County Museum of Natural History, one worker deposited in Instituto de Zoologia Agricola, one worker deposited in National Museum of Natural History.

Etymology

The specific name refers to the relatively minute size of the compound eyes that characterize workers of this species.

References

Albuquerque, N.L.d., Brandão, C.R.F. 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 (doi:10.1590/S0031-10492009002300001).

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.
Feitosa R. dos S. M. and A. S. Ribeiro. 2005. Mirmecofauna (Hymenoptera, Formicidae) de serapilheira de uma área de Floresta Atlântica no Parque Estadual daCantareira São Paulo, Brasil. Biotemas 18: 51-71.
Figueiredo C. J. de, R. R. da Silva, C. de Bortoli Munhae, and M. S. de Castro Morini. 2013. Ant fauna (Hymenoptera: Formicidae) attracted to underground traps in Atlantic Forest. Biota Neotrop 13(1): 176-182
Mentone T. O., E. A. Diniz, C. B. Munhae, O. C. Bueno, and M. S. C. Morini. 2011. Composition of ant fauna (Hymenoptera: Formicidae) at litter in areas of semi-deciduous forest and Eucalyptus spp., in Southeastern Brazil. Biota Neotrop. 11(2): http://www.biotaneotropica.org.br/v11n2/en/abstract?inventory+bn00511022011.
Oliveira Mentone T. de, E. A. Diniz, C. de Bortoli Munhae, O. Correa Bueno and M. S. de Castro Morini. 2012. Composition of ant fauna (Hymenoptera: Formicidae) at litter in areas of semi-deciduous forest and Eucalyptus spp., in Southeastern Brazil. Biota Neotrop 11(2): 237-246.
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
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.