First record of the ant genus Oxyepoecus (Formicidae: Myrmicinae: Solenopsidini) in Chile, with remarks on its geographical range

Primer registro del género de hormigas mirmicinas Oxyepoecus (Formicidae: Myrmicinae: Solenopsidini) para Chile con consideraciones sobre la amplitud de su distribución

Cuezzo, Fabiana

CONICET - Instituto Superior de Entomología «Dr. A. Willink». Facultad de Ciencias Naturales e IML, UNT. Miguel Lillo 205. CP 4000, San Miguel de Tucumán, Argentina; e-mail: fcuezzo@csnat.unt.edu.ar

RESUMEN. El género de hormigas Oxyepoecus (Formicidae: Myrmicinae: Solenopsidini) Santschi, 1926, está compuesto por 16 especies reconocidas como válidas. Tres de estas especies, O. inquilinus, O. bruchi y O. daguerrei, son consideradas actualmente como vulnerables (VuD2) e incluidas en la lista roja de especies amenazadas. El propósito de este trabajo es registrar, por primera vez, una de estas especies para Chile: O. inquilinus. Esta nueva localidad constituye el límite de distribución austral de este género rara vez recolectado.

PALABRAS CLAVE. Especies amenazadas; Formicidae; América del Sur; Chile.

ABSTRACT. The ant genus Oxyepoecus (Formicidae: Myrmicinae: Solenopsidini) Santschi, 1926 has 16 species recognized as valid. Three of these species: O. inquilinus (Kusnezov, 1952), O. bruchi Santschi, 1926 and O. daguerrei (Santschi, 1933) are considered as vulnerable (VuD2) and included in the Red List of threatened species. The aim of this paper is to record one of these species: O. inquilinus in Chile for the first time, adding a new locality to be considered as the southernmost limit of distribution for this relatively rarely collected ant genus.

KEY WORDS. Endangered species; Formicidae; South America; Chile.

The ant genus Oxyepoecus (Formicidae: Myrmicinae: Solenopsidini) was created by Santschi (1926). Oxyepoecus is exclusively neotropical and workers are seldom collected. The genus was reviewed by Kempf (1974) and recently the Vezenyii group was proposed and reviewed by Albuquerque & Brandão (2004). The last authors propose a new generic diagnosis dividing Oxyepoecus in two complex: Vezenyii with 11 species and Oxyepoecus grouping the remainder five species.
Oxyepoecus can be distinguished from other Solenopsidini ant genera by the following suite of characters: 11 segmented antennae with a 3-segmented apical club; clypeus with four teeth; propodeum with a pair of teeth and integument always extensively sculptured.
As Albuquerque & Brandão (2004) say: «all known individuals of Oxyepoecus were obtained either by chance discoveries or specialized collecting techniques applied sporadically at very few and scattered localities».
The use of new techniques and protocols, as is the case of leaflitter Winkler extractor, soil samples and/or Berlesse funnel to sample soil and leaf litter, has permitted to obtain, in a more efficient way, relatively small ants that inhabit specifically these niches, up to a decade ago very little studied.
Until today, the southern limit of Oxyepoecus distribution was the parallel 31º, in Argentina (Cordoba, Alta Gracia) (fig.2). O. inquilinus (Kusnezov, 1952) was formerly recorded from Central and Southern Brasil and Tucumán, in northern Argentina. The northern limit of its distribution was recently mentioned by Fernandez (2002) to Llanos Orientales, Meta Department, Orinoco Basin, Colombia. Here, I provide the first record of Oxyepoecus in Chile, being the new southernmost record that is known for this genus.
One worker of Oxyepoecus inquilinus was collected in 06 February 2005 by M. Ramírez and F. Labarque (Museo de Ciencias Naturales B. Rivadavia, Buenos Aires, Argentina; MACN) from litter submitted to a Berlese funnel, taken in Chile, Reg. X: Osorno, P.N. Puyehue, Aguas calientes, sendero «El Pionero» (40º 44' 13.9''S-72º 18' 23.3''W). 70 m.bsl. This National Park is a reserve of Valdivian forest (see fig. 1). This Ecoregion is one of the most particular environments of Chile, with a high degree of endemism and one of the most diverse biomes of the planet. Conservation International identified this temperate region as part of 25 places with most high value to conserve biodiversity in the world level. It is possible that this species has a extremely localized population and this may be the reason for this species to be included in the Red List (SISG, 1996) as VuD2 (Vulnerable, population is characterized by an acute restriction in its area of occupancy, typically less than 100 km2, or in the number of locations, typically less than five). Other two species of Oxyepoecus: O. bruchi Santschi, 1926 and O. daguerrei (Santschi, 1933) are considered as endangered species too.
The specimen will be deposited at MACN. I thank Dr. M. Ramirez for providing the specimens of Oxyepoecus inquilinus, along with innumerable additional specimens of ants collected throughout Chile. Other examined material: Oxyepoecus inquilinus, 1 worker, type material (IFML, Kusnezov coll).

Fig. 1. Record of O. inquilinus in the Valdivian Temperate Forest, Chile.

Fig. 2. Distribution of Oxyepoecus inquilinus showing all known records of O. inquilinus

ACKNOWLEDGMENTS

This work was supported by a grant of CONICET, Argentina. To the reviewers for thier helpfull comments.

LITERATURE CITED

1. ALBUQUERQUE, N. N. & 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 44 (4): 55-80.
2. FERNÁNDEZ, F. 2002. New ant records for Colombia and South America (Hymenoptera: Formicidae) Revista Colombiana de Entomología 28(2): 215.
3. KEMPF, W. W. 1974. A review of the Neotropical ant genus Oxyepoecus Santschi. Studia Entomologica (N.S.) 17: 471-512.
4. KUSNEZOV, N. 1952. Acerca e las hormigas simbióticas del género Martia Forel. Acta Zoológica Lilloana 10: 717-722.
5. SANTSCHI, F. 1926. Deux nouvelles fourmis parasites de l'Argentine. Folia Myrmecologica et Termitologica 1: 6-8.
6. SOCIAL INSECTS SPECIALIST GROUP 1996. Oxyepoecus inquilina. En: IUCN 2006. 2006 IUCN Red List of Threatened Species. www.iucnredlist.org. Downloaded on 05 December 2006.         [ Links ]         [ Links ]         [ Links ]         [ Links ]         [ Links ]         [ Links ]

Recibido: 15-02-2007;
aceptado: 4-05-2007