Chrotopterus auritus ( Peters , 1856 ) ( Chiroptera , Phyllostomidae ) : first record for the state of Rio Grande do Norte , northeastern Brazil

Chrotopterus auritus is a phyllostomid bat with a wide distribution in the Neotropics. It has been recorded in Brazil’s 6 biomes but with few records in the Caatinga. We provide the first record of C. auritus for Rio Grande do Norte state, northeastern Brazil, based on records from 2 caves, Três Inchu and Gruta da Carrapateira. The nearest records are ca. 400 km southeast in Ceará state and ca. 350 km northwest in Pernambuco state. Our new records fill the northeastern distributional gap of C. auritus in Brazil and South America.

Chrotopterus auritus (Peters, 1856) is one the largest phyllostomid bats and the single representative of the genus Chrotopterus Peters, 1865(Simmons 2005).As well as Vampyrum spectrum (Linnaeus, 1758) and Trachops cirrhosus (Spix, 1823), C. auritus is considered a predominantly carnivorous species (Ferrarezzi & Gimenez 1996) but occasionally including insects (Medellín 1988) and fruits (Bernard 2002) in its diet.It is known to occur in southern Mexico, Central America, Colombia, Venezuela, Guyana, Surinam, French Guiana, Brazil, Ecuador, Peru, Bolivia, Paraguay, and northern Argentina (Williams & Genoways 2008).In Brazil, this species has been recorded in all biomes (Paglia et al. 2012) but there are few records for the Caatinga (Fig. 1; Table 1).The Caatinga is restricted to Brazil and is a mosaic of tropical dry forest with xeric shrublands (Leal et al. 2003).With a predominant semi-arid climate (MMA 2017) and located in the Northeast Region, the Caatinga has an area of over 800,000 km 2 , which represents about 11% of Brazil's territory, and covering 9 states and the northern part Minas Gerais.Herein, we provide the first occurrence record of Chrotopterus auritus for the state of Rio Grande do Norte, northeastern Brazil, based on records from 2 separate caves in the Caatinga on the west side of the state.
On 28 August 2015 at 23:40 h an individual of C. auritus was observed and photographed in the Gruta da Carrapateira.Capture attempts were unsuccessful but the individual was identified through direct observation using binoculars and photographic records.The calcareous cave is located in the municipality of Felipe Guerra (05°33ʹ38.2ʺS, 037°39ʹ50.3ʺW, altitude ca.32 m) about 348 km west of Natal and has 5 entrances and a linear development of 242.2 m.
The second record is based on a colony of 8 individuals and an adult male captured with a hand net (Fig. 3) inside the Três Inchu cave (06°03ʹ07ʺ S, 037°54ʹ03ʺ W) on 18 December 2015.The Três Inchu is a marble cave located in the municipality of Martins, ca.362 km from Natal, with a linear development of 146.0 m and 5 recognized entrances, some of which are skylights, providing for photic zones inside.
The Três Inchu specimen was handled in accordance with Sikes et al. (2011), euthanized and fixed in 10% formaldehyde and preserved in 70% ethanol with subsequent extraction of the skull (Fig. 2).Cranial and external measurements were taken following Vizotto & Taddei (1973) using a digital caliper (0.2 mm).The specimen was collected under permit SISBIO/IBAMA 52492-1 and is deposited in the mammal collection of the Federal University of Sergipe (CMUFS) under voucher number CMUFS 259.
Our voucher of Chrotopterus auritus has the set of characters that distinguish this species from other members of the Phyllostominae, such as its large size (forearm 74-83 mm), presence of 1 pair of lower incisors and 3 lower premolars (Fig. 2), rudimentary tail, calcar longer than the foot, large rounded ears not connected by a band, horseshoe of noseleaf cup-shaped and continuous with spear, and long thumb with a large strongly curved claw (Fig. 3) (Medellín 1989; Williams   1980) and Pernambuco (Sousa et al. 2004) states, respectively.The presence of C. auritus within the Caatinga may be unusual, since there are only 6 previous records from this biome (Fig. 1; Table 1).The records are: in xeric-woodlands of Caatinga (Sá-Neto & Marinho-Filho 2013); in Chapada Diamantina National Park in Bahia state (Gregorin & Mendes 1999;Sbragia & Cardoso 2008); in transition areas of Caatinga and the Amazon (Uieda et al. 1980); in humid forest enclaves within the Caatinga known as "Brejos de Altitude" (Sousa et al. 2004); and in the southern limit of the Caatinga in Jaíba, northern Minas Gerais state (Nogueira et al.2015).Moreover, 4 of these records were obtained from underground cavities (Gregorin & Mendes 1999; Sbragia & & Genoways 2008).
Cranial and external measurements of the voucher, in millimeters, are: forearm length (84.6), hind foot length (21.1), calcar (22.3), ear (36.2), greatest length of skull (37.12), condylobasal length (32.41), breadth of braincase (14.28), post-orbital constriction (6.06), breadth across upper molars (12.18), breadth across upper canines (7.92), length of mandible (24.78) and length of maxillary tooth row (15.18).These measurements are within the known range for the species (see Medellín 1988).In the case of the individual from Gruta da Carrapateira, not captured, it was possible to see external diagnostic characters of C. auritus, such as the cup-shaped horseshoe of the noseleaf and the long thumbs with large claw.
Our records of Chrotopterus auritus from Rio Grande do Norte fill the distributional gap of this species in northeastern  Cardoso 2008; Uieda et al.1980;Nogueira et al. 2015).
Chrotopterus auritus is known to roostin caves, abandoned mines, buildings, and hollow trees (Reid 2009).It inhabits mature evergreen forest and deciduous forests, but records in this latter formation are less common (Medellín 1989).Because C. auritus is a top predator, more regularly found in undisturbed habitats, its presence is considered an indicator of healthy forests (Medellín 1989;Gorrensen & Willig 2004).Individuals generally form small groups from 3 to 6 individuals in their roost (Arita & Vargas 1995;Bredt et al. 1999).When roosting in caves, this species is commonly found in cohabitation with other bat species (Coimbra et al. 1982;Trajano 1985;Bredt et al. 1999) Caves in the Caatinga, including those in the state of Rio Grande do Norte, may be important roosting sites for C. auritus, and the presence of a high density of caves in the landscape may be a good predictor of a potential occurrence of this species.Furthermore, roosting in caves may provide benefits to C. auritus besides providing stable roost conditions.The cohabitation with others bats inside caves may allow for the predation of other smaller bats, a behavior already reported for C. auritus (Bordignon 2005;Witt & Fabian 2010).
Anincrease of bat inventories in Rio Grande do Norte, both in caves as well as in other habitats, should provide a better understanding of the distribution of C. auritus and more generally the species richness in this state and in the Caatinga biome.

Figure 1 .
Figure 1.Records of Chrotopterus auritus in Brazil.The numbers corresponding to the records are indicated in Table 1.Blue stars represent the new records from the state of Rio Grande do Norte, Brazil.

Figure 2 .
Figure 2.Dorsal, ventral and lateral views of the skull and lateral view of the mandible (scale bar=10 mm) of Chrotopterus auritus (CMUFS 259) from Três Inchu cave, Martins municipality, Rio Grande do Norte state, northeast Brazil.In detail, front view of the mandible showing the presence of 2 incisors (scale bar = 5 mm).

Figure 3 .
Figure 3. Chrotopterus auritus photographed at the Gruta Três Inchu, Martins municipality, Rio Grande do Norte state, northeast Brazil.Note the long thumb (arrow a) with a large strongly curved claw and the cup-shaped horseshoe of noseleaf (arrow b).

Table 1 .
Blue stars represent the new records from the state of Rio Grande do Norte, Brazil.

Table 1 .
Locality records for Chrotopterus auritus in Brazil.The code numbers refer to the points shown in Figure 1.