Lasiurus ega (Gervais 1856)

Bezerra, Alexandra M. R. & Marinho-Filho, Jader, 2010, Bats of the Paranã River Valley, Tocantins and Goiás states, Central Brazil, Zootaxa 2725, pp. 41-56 : 51-54

Lasiurus ega (Gervais 1856)

Distribution. From southwestern USA, Mexico to Bolivia, Trinidad, Brazil, Paraguay, Uruguay, and Argentina. Occurs in almost all Brazil, but Alagoas, Amapá, Goiás, Maranhão, Rio Grande do Norte, Roraima, Rondônia, Sergipe, and Tocantins ( Peracchi et al. 2006; Reis et al. 2007).

Habitat. Occurs in both mesic and xeric environments from tropical forest to grassland savannas and also in close association with human buildings ( Kurta & Lehr 1995). Despite being widely distributed, in Brazil it is not commonly found, inhabiting open and forested areas of the Cerrado biome ( Marinho-Filho et al. 2002). We captured two individuals with mist nets near São Domingos River (12° 54’ 50.8” S – 47° 34’ 0.7” W), in Paranã, TO.

Comments. Lasiurus ega is included in the subgenus Dasypterus , which also includes L. intermedius and L. xanthinus , and is often considered synonym of xanthinus ( Simmons 2005; Gardner 2008). Barquez et al. (1999) consider Dasypterus as a full genus and distinct from Lasiurus .

Voucher specimens. One adult female – CHUNB 1244 ; one adult male – CHUNB 1237 .

New records. The 23 bat species found in the Valley of the Paranã River accounts for 23, 28% of the chiropteran fauna estimated for the Cerrado biome ( Marinho-Filho et al. 2002). Five species registered in this study are new records for the state of Goiás and nine for the state of Tocantins ( Table 1). According to distribution maps by The IUCN Red List of threatened species ( IUCN 2009) the presence of these species was expected but no previous records could corroborate the proposed distributions that remained presumptive until the present study. The new records for the state of Goiás are D. ecaudata , T. bidens , A. obscurus , U. magnirostrum , and E. furinalis , whereas R. naso , G. soricina , C. perspicillata , A. obscurus , P. parnellii , N. albiventris , N. leporinus , M. molossus , and L. ega are new records for the state of Tocantins. Chrotopterus auritus has their distribution extended to northern Goiás state, in Alvorada do Norte. Fracasso and Salles (2005) have also registered the species in northern Goiás, but as fossil in caves.

The chiropteran fauna for the state of Tocantins increased significatively to 19 species with these nine new records. Tocantins is a new federation unit created in 1988, in the northern portion of the former state of Goiás. Is lies in the transition area between Amazon and Cerrado biomes ( IBGE 2004 b), where biodiversity inventories are still scarce .

A previous study on the local herpetofauna indicated the region is suffers a noticeable influence from the adjacent semiarid Caatinga biome ( Werneck & Colli 2006) as well as from Amazon, through the gallery forests ( Eiten 1972; Ackerly et al. 1989). Mammalian fauna studies are scarce in state of Tocantins and the proximity and coexistence side-by-side of physiognomies from these distinct ecosystems added with endemic species to northern portion of the Cerrado biome, like Thyroptera devivoi ( Gregorin et al. 2006) , makes this area biogeographically important. The chiropteran fauna of this region seemingly reflects this ecotone character, where endemic species from savannas ( L. dekeyseri ) coexist with species whose distributions is primarily associated to other biomes (e.g., R. naso , from Amazon, and T. bidens , whose principal distribution is through Atlantic Rainforest) enlarging its limits into the Cerrado.

Species of special interest. Besides the new records, some species collected here are important because they are rare (at least in scientific collections) or threatened (i.e. included in some list of endangered species). Eleven species collected in this study can be considered in one of these categories. Besides being the only Cerrado endemic bat species, Lonchophylla dekeyseri is also included as “Threatened” in the Brazilian official list of threatened species ( Machado et al. 2008), and as ‘Near Threatened” in IUCN 2009 Red List ( Sampaio et al. 2008), because ongoing human induced habitat loss and degradation. Another species included in the IUCN 2009 Red List, as “Data Deficient”, is T. bidens , with taxonomic problems as well as absence of recent information on its extent of occurrence, status and ecological requirements ( Barquez & Diaz 2008).

Lonchophylla dekeyseri and T. bidens together with D. ecaudata , C. auritus , L. brasiliense , M. minuta , U. magnirostrum , N. albiventris , N. leporinus , E. furinalis , and L. ega are among those species that are not commonly captured and, consequently, are rare in scientific collections. Their biology, distribution, ecology, and even taxonomy, are still poorly known. The species D. ecaudata , C. auritus , and U. magnirostrum are supposed to be naturally rare ( Marinho-Filho et al. 2002). Eptesicus furinalis , L. ega , M. minuta , and N. albiventris are insectivorous specialists and their small numbers in the present study may be associated to the fact that mist netting is not an efficient method to catch specialist insectivorous bats, since the highly specialized sonar systems in these species can detect and avoid mist nets.

Natural history notes. Desmodus rotundus and P. lineatus were the species most frequently collected in both dry and rainy seasons. Carollia perspicillata and A. obscurus were more frequent in the dry season ( Table 2).

Diphylla ecaudata , C. auritus , S. lilium , T. bidens , U. magnirostrum , E. furinalis , L. ega , M. minuta , P. parnellii , and R. naso were recorded only in the rainy season. All these species, but the S. lilium , are seen as uncommon, and the last five species are insect specialists ( Marinho-Filho et al. 2002). The greater species richness was found in the rainy season ( Table 2) and was in part due to bats of insectivorous habits. The rainy season is the period of greater abundance of insects in the Cerrado ( Marinho-Filho et al. 1997).

All four pregnant females registered in this study (two D. rotundus , one A. obscurus , and one N. albiventris) were captured in the very end of the dry season. This pattern is consistent with giving birth in the beginning or during the rainy season, when resource availability tends to be high ( Willig 1985).

Karstic environments importance. The higher bat species richness was found in Alvorada do Norte, state of Goiás, where limestone outcrops indicate karstic environments. Nine from total of 14 species sampled in this locality ( D. ecaudata , D. rotundus , L. dekeyseri , A. caudifer , C. auritus , M. minuta , M. bennettii , T. bidens , and U. magnirostrum ) were captured in front of limestone outcrops. This kind of geological formation is associated with a number of cavities, rock crevices and caves that represent roosting opportunities for a diversified bat community. However the calcareous soils also associated to ‘karstic’ reliefs are very productive, reach the highest land acquisition prices and are the first to be explored in the region. Alvorada do Norte lies in a region of increasing human activity, and Cerrado conversion in productive soybean and cotton plantations is presently very intense at this moment. However it has also a special bat community living in a particular environment that should be protected. The most effective measure to counteract the human pressure over this delicate environment seems to be the creation of a conservation unit in the region.