Odonata ( Insecta ) from Nova Xavantina , Mato Grosso , Central Brazil : Information on species distribution and new records

issue that limits the ability to establish effective strategies for the conservation of most tropical species (Whittaker et al. 2005; Leite et al. 2008; Diniz et al. 2010). These impediments also prevent the building of a complete understanding of biogeographical patterns of species (Diniz et al. 2010). However, it also posit the need to circumvent these limitations, either using new techniques, such as species distribution modeling (e.g. Almeida et al. 2010), or by concentrating sampling efforts on areas that represent knowledge gaps (Diniz et al. 2010). Only 2.2% of Cerrado Biome is legally protected (Klink and Machado 2005).The intense land cover changes occasioned mainly by agricultural and cattle farming (DeFries et al. 2013) can lead sensitive species to local extinction before they have been described. Although the number of surveys of other taxa in the state of Mato Grosso have increased in recent years (Salles et al. 2004a, b; 2011; Shimano et al. 2010a, 2011b; Nogueira and Cabette 2011; Dias–Silva et al. 2010; Polegatto and Batista 2007), this knowledge gap persists to Odonata (De Marco and Vianna 2005), since there is only one work in the region (Juen et al. 2007). Thus, our goal is to present a list of adult odonate species collected in Cerrado streams in Nova Xavantina, Mato Grosso, Central Brazil, providing new records and information on species distribution.

issue that limits the ability to establish effective strategies for the conservation of most tropical species (Whittaker et al. 2005;Leite et al. 2008;Diniz et al. 2010).These impediments also prevent the building of a complete understanding of biogeographical patterns of species (Diniz et al. 2010).However, it also posit the need to circumvent these limitations, either using new techniques, such as species distribution modeling (e.g.Almeida et al. 2010), or by concentrating sampling efforts on areas that represent knowledge gaps (Diniz et al. 2010).
Only 2.2% of Cerrado Biome is legally protected (Klink and Machado 2005).The intense land cover changes occasioned mainly by agricultural and cattle farming (DeFries et al. 2013) can lead sensitive species to local extinction before they have been described.Although the number of surveys of other taxa in the state of Mato Grosso have increased in recent years (Salles et al. 2004a, b;2011;Shimano et al. 2010aShimano et al. , 2011b;;Nogueira and Cabette 2011;Dias-Silva et al. 2010;Polegatto and Batista 2007), this knowledge gap persists to Odonata (De Marco and Vianna 2005), since there is only one work in the region (Juen et al. 2007).Thus, our goal is to present a list of adult odonate species collected in Cerrado streams in Nova Xavantina, Mato Grosso, Central Brazil, providing new records and information on species distribution.

Study area
We collected adult Odonata specimens in nine streams, tributaries of the Ribeirão Antártico and Pindaíba River Basins, both belonging to the Rio das Mortes River Basin in Nova Xavantina, eastern Mato Grosso, Brazil (Table 1 and Figure 1).
The predominant vegetation in the study area is typical of the Cerrado Biome.The climate is humid tropical, Aw according to Köppen system, with two distinct seasons:

Introduction
The order Odonata currently comprises about 6.000 species (Trueman 2007), but recent studies estimate the richness of this group to be 7000 species (Kalkman et al. 2008).About 1.727 species are known in the Neotropics (von Ellenrieder 2009), of which 220 are endemic (Pinto and Carvalho 2009).The Odonata is represented by three suborders, Zygoptera, Anisoptera and Anisozygoptera, the last one recorded only in Japan and eastern Himalayas (Kalkman et al. 2008).The suborders Anisoptera and Zygoptera are present in Brazil, comprising about 800 species (Souza et al. 2007), which represents 46% of the Neotropical fauna.Considering that Brazil is the largest country in South America, the number of species may be much higher, since only 29% of the Brazilian territory has been surveyed for species of Odonata (De Marco and Vianna 2005).However, nowadays this percentage could be much higher, since there are a growing number of new records and new species being described (Pinto and Lamas 2011;Lencioni 2013).
Odonata have a complex life cycle, with an aquatic larval stage and a terrestrial/aerial adult stage.They are widely distributed in tropical and temperate freshwater ecosystems (Corbet 1999).Anisoptera are robust, conspicuous insects in which the base of the wings are different, whereas Zygoptera are less robust and have the base of the wings similar.Adult males of some species generally defend territories around streams (Resende 2010).Given the complexity of their life cycle, several authors have pointed out the importance of the group in studies evaluating and monitoring the conditions of freshwater environments (Oertli 2008;Silva et al. 2010;Pinto et al. 2012;Monteiro Júnior et al. 2013).
The lack of taxonomic and biogeographic knowledge, called Linnean and Wallacean shortfalls, respectively (Whittaker et al. 2005), is widely recognized as a real Abstract: Odonates are found in all freshwater environments, and are specially species rich in tropical freshwater ecosystems.Currently about 800 odonate species are known to Brazil, but only 29% of the Brazil territory have been surveyed for this group.Here we provide a species list with information on distribution and new records for Odonata in nine streams in Nova Xavantina, Mato Grosso, Central Brazil.We used the scan procedure with a fixed area for three days in each stream between 10:00 and 14:00h.We collected 1038 dragonfly specimens belonging to 67 species, which represents 8% of the known Brazil odonate fauna.Additionally, five new records for the study area are presented.a rainy season (October-March) and a dry season (April -September) with annual mean temperature of 24.77° C and rainfall of 1.500 mm (Klink and Machado 2005).The main economic activity in the region is cattle farming and agriculture (Alencar et al. 2004).

Sampling
We collected adult Odonata specimens in April and August 2011, using the scanning procedure in fixed areas (De Marco and Resende 2002;Juen and De Marco 2011).We collected Odonata with a sweep net for three days in each stream between 10:00h and 14:00h.We followed the methodology of Lencioni (2005) for mounting and packaging the specimens.Vouchers are housed at the Zoobotanical collection "James Alexander Ratter", Universidade do Estado de Mato Grosso at Nova Xavantina, Laboratório de Entomologia, Departamento de Biologia, Nova Xavantina, Mato Grosso, Brazil.We used the following identification keys: Borror (1942); Garrison et al. (2006); Lencioni (2005aLencioni ( , 2006b) ) to identify specimens.
Libellulidae was the most speciose family, possibly due to high dispersal and termorregulatory abilities (Corbet 1999;May 1976).Coenagrionidae was the most abundant family, mainly the genus Argia (Rambur, 1842).This genus is widely distributed throughout the New World, and highly diverse in the Neotropics (Caesar and Wenzel 2009), probably due to endophytic oviposition and climbing behavior of larvae (Fulan and Henry 2007).
Although the number of studies dealing with behavioral aspects of Odonata (e.g.The genus Oxyagrion (Selys, 1876) is composed of 23 species occurring in South America, of which 18 occur in Brazil (Dalzochio and Rodrigues 2009).The genus Oligoclada Karsch, 1890 occurs throughout South America, with high richness in the Amazon.Recently, Oligoclada xanthopleura Borror, 1931 was registered in Pará and Mato Grosso (Pinto and Lamas 2011).This substantial increase of new records is due mainly to increased sampling efforts in different Brazilian regions.However, some genera, such as Argia, Acanthagrion and Telebasis are very common in entomological collections, but with many undescribed species (Paulson 2009).
This study adds new knowledge to the odonate fauna of Nova Xavantina, as well as the record of a new genus being described by Muzon J. (F.A.A. Lencioni pers.com.).

Telebasis gigantea Daigle, 2002
Material Examined: 3 ♂ This species is found on the banks of streams and ponds shaded (Garrison 2009).According to this author this species appears late in the afternoon between 16:30h and 17:30h.Some species of this genus are found in slightly altered environments, possibly because its larvae have a climbing behavior (Fulan and Henry 2007).

Discussion
We found high diversity of Odonata species in Nova Xavantina county, Mato Grosso.It represents 8% of the recorded fauna of Brazil, with the first record to Telebasis gigantea.We suggest a concentration in sampling effort for the region, in order to complete the Odonata fauna of the state.For example, in the suborder Anisoptera we sampled only Libellulidae family.The absence of records for Aeshnidae, Gomphidae and Corduliidae may be associated with the difficulty in collecting individuals of these families since they are excellent fliers, and some genera, like Gynachanta, may have phytotelmata individuals with crepuscular habits (Bede et al. 2000).These difficulties are reflected in the scarcity of individuals in entomological collections and not necessarily in their biogeographical distribution.Thus, the check list presented here adds important information that will foster future studies on odonate species distribution.

Figure 1. Streams
sampled at Nova Xavantina, eastern region of the State of Mato Grosso, Brazil.

Table 1 .
Locality and geographic coordinates of the streams sampled.