Oxyepoecus longicephalus

Oxyepoecus longicephalus
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Solenopsidini
Genus:	Oxyepoecus
Species:	O. longicephalus
Binomial name
	Oxyepoecus longicephalus; Albuquerque & Brandão, 2004

O. longicephalus was recorded in only one locality at south Brazil, and one at southern Brasil, geographically separated.

Identification

Albuquerque and Brandao (2004) - The exclusive character of the workers of O. longicephalus is mainly the proportion between the head length and head width (very elongate, low c.i.); also the irregularly reticulate sculpture over the body (visible only at magnifications over 80 X).

Keys including this Species

Key to Oxyepoecus species

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: -23.25° to -29.5°.


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

Known only from the worker caste.

Nomenclature

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

longicephalus. Oxyepoecus longicephalus Albuquerque & Brandão, 2004: 69, figs. 4a-c (w.) 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 paratype within brackets t.l.= 3.00 (3.06); h.l.= 0.72 (0.72); h.w.= 0.48 (0.50); s.l.= 0.42 (0.46); m.l.e.= 0.08 (0.12); m.w.pr.= 0.42 (0.45); a.l.= 0.84 (0.84); h.f.l.= 0.41 (0.45); m.w.p.= 0.18 (0.22); m.w.pp.= 0. 30 (0. 30); c.i. 66 (69). Color chestnut brown to dark brown. Integument smooth and shining, with the following exceptions: frontal carinae longitudinally costulate, prolonged posteriorly, surpassing the level of the superior orbit of the compound eyes; genae with well marked longitudinal rugae that do not reach superiorly the inferior orbit of compound eyes but reach inferiorly the mandibular insertion; pronotum with some irregular and superficial rugae; the neck, the mesopleuron (anepisternum and katepisternum), the metapleuron and the propodeum almost entirely covered by irregularly reticulate sculpture, except around the propodeal spiracle, which is smooth; the inferior region of the metapleuron with two longitudinal and well marked costulae that prolong over the metapleural gland bulla; superior face of the petiole peduncle and lateral face of the petiole also with the irregularly reticulate sculpture; the superior and lateral face of the postpetiole with some irregular rugae that give a rough aspect. Hairs abundant, short and decumbent, irregularly distributed on cephalic disc; scarce, long, suberect and relatively curved forwards on pronotum; metapleuron and mesopleuron with scarce and short hairs; propodeum, petiolar node, postpetiole, and gaster with some long and erect hairs, somewhat backwards oriented.

Head. Mandibles elongated with a broad and relatively shallow diastema between the basal and subbasal tooth. Anterior teeth of clypeus with small, blunt and lobe-like lateral denticles. Frontal carinae relatively short, subparallel, reaching the level of the inferior orbit of the compound eyes, the maximum width between their outer edges less than a fifth of the head width. Compound eyes small, with about 3-5 facets r.g.d.; total number of ommatidia about 8. Antennal scape failing to reach the occipital corner by a distance larger than the maximum thickness of the scape. Funicular segment I as long as II-IV combined, segments II-VII distinctly broader than long, VIII and IX as long as broad.

Mesosoma. Promesonotum immarginate in front and laterally; shoulders marked, but without a defined angle. Metanotal groove perceptible by a break in the profile. Dorsal face of the propodeum posteriorly with two acute teeth. Declivous face laterally marginate and weakly carinate.

Petiole node high and rounded at superior face, antero-posteriorly compressed but not scale-like, about 2/3 as broad as postpetiole; subpetiolar process as a sagital and undulated keel anteriorly ending in a prominent tooth-shaped plate. The postpetiole broad, in a scale like fashion, the level of the superior face lower than the petiole node; subpostpetiolar process small, almost imperceptible, extremely shallow.

Type Material

Holotype worker, Brasil: Rio Grande do Sul: Itatí 29°30’S, 50°10’W, 28.v.1997, J. Ketterl [col.], CPCN Pró-Mata, deposited in Museu de Zoologia da Universidade de Sao Paulo. Paratype: workers. Brasil: Rio Grande do Sul: Itatí 29°30’S 50°10’W, 29.v.1997, J. Ketterl [col.], CPCN Pró-Mata deposited in MZSP. São Paulo: Cunha 23°15’S, 45°00’W, 21-22.iv.2001, A.A. Tavares, R.R. Silva cols, P.E. Serra do Mar, Winkler, deposited in MZSP.

Etymology

The shape of the head (f.f.v.) where the length is more developed than the width.

References

Albuquerque, N.L.d., Brandão, C.R.F. 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).
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 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 (São Paulo) 44: 55-80.
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.
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
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.