New records and distribution for the Neotropical ant genus Ochetomyrmex Mayr ( Hymenoptera : Formicidae )

Recently reclassified in the Myrmicinae tribe Attini (Ward et al., 2014), the Neotropical ant genus Ochetomyrmex Mayr, 1878 (Formicidae,Ward et al., 2014) includes two valid species: O. semipolitus Mayr, 1878 and O. neopolitus Fernández, 2003 restricted to the Neotropical region. Both species are comparatively small, monomorphic and cryptobiotic, found nesting in the leaf litter of tropical lowland forests east of the Andes (Fernández, 2003). Limited information is available about where they are found, as little is known about Ochetomyrmex biology. This study presents an update to known distribution of Ochetomyrmex, adding recent information available from several sources (AntWeb, 2014; Baccaro et al., 2010, 2012; Boscardin et al., 2012; Delabie et al., 2009; Groc et al., 2009, 2013; Miranda et al., 2012, 2013; Santos et al., 2008; Souza et al., 2012; Vittar, 2008; Wild, 2007; Wilkie et al., 2007, 2009). Unpublished records from the Collection of Formicidae Cocoa Research Center (CPDC) and samples collected in Pantanal of Mato Grosso state of Brazil were added. Abstract New records and known distribution from species of the genus Ochetomyrmex (Mayr) in the Neotropics are presented, emphasizing the first occurrence of Ochetomyrmex neopolitus (Fernández) in the Mato Grosso Pantanal region, a sub-region of Cáceres, Brazil.


Introduction
Recently reclassified in the Myrmicinae tribe Attini (Ward et al., 2014), the Neotropical ant genus Ochetomyrmex Mayr, 1878(Formicidae,Ward et al., 2014) includes two valid species: O. semipolitus Mayr, 1878 andO. neopolitus Fernández, 2003 restricted to the Neotropical region.Both species are comparatively small, monomorphic and cryptobiotic, found nesting in the leaf litter of tropical lowland forests east of the Andes (Fernández, 2003).Limited information is available about where they are found, as little is known about Ochetomyrmex biology.
The occurrence of O. neopolitus in the Pantanal of Mato Grosso is possibly a consequence of Amazonian vegetation in the floristic composition of the study area, as the vegetation here is strongly influenced by adjacent phytogeographic areas, including the Amazon and Chaco biomes (Adámoli, 1982;Silva et al., 2000;Alho & Gonçalves, 2005;Junk et al., 2006).Although other studies were carried out in this biome (e.g.Marques et al., 2010Marques et al., , 2011;;Silva et al., 2013, Corrêa et al., 2006), this species has not yet been documented in other regions of the Pantanal.
The genus Ochetomyrmex is endemic to South America and it is rarely collected at east of the Andes, between 6º N and 30º S (Fernández, 2003).O. neopolitus occurs in Guiana, Suriname, French Guiana, Brazil (Acre, Pará, Amazonas, Mato Grosso, Tocantins, and Bahia), Bolivia, Peru, Ecuador and Colombia.On the other hand, O. semipolitus seems to be more common in the Amazon and Cerrado and is not found in the Atlantic Forest of southeastern Brazil.It is found in Guyana, Suriname, French Guiana and Brazil (Acre, Amazonas, Rondônia, Mato Grosso, Goiás, Minas Gerais, Pará, Rio Grande do Sul, and Roraima), Argentina, Peru, Bolivia, Ecuador and Colombia.The transition between the forest fragment and riparian, and terra firma forests appears as a gradient of occurrence for several ant species, particularly Odontomachus spp., Pachycondyla spp., Camponotus rapax, and Ochetomyrmex semipolitus.Finally, the habitat quality of the pristine, terra firma forest was mostly marked by the diversity of the genus Pheidole, and the occurrence of other species such as O. semipolitus (Delabie et al., 2009).
The distribution of Ochetomyrmex in Brazil and in the Neotropics is possibly underestimated in the literature, because their morphology is rather close to Pheidole, frequently provoking taxonomical confusion between genera.

Fig 1 .
Fig 1. Distribution of Ochetomyrmex neopolitus and Ochetomyrmex semipolitus in the Neotropics, based on information from literature, new records from the collection of Formicidae Cocoa Research Center (CPDC), and samples collected in Pantanal of Mato Grosso.