Distribution extension and new record of Myotis atacamensis ( Lataste , 1892 ) ( Chiroptera : Vespertilionidae ) in Chile

Myotis atacamensis is a poorly known bat species endemic to the central portion of the pacific coast of South America, where it is known from the province of Lambayeque, Peru (latitude 5° S), to the province of Elqui (latitude 30° S), Chile. Here, we report the first record of M. atacamensis for the province of Choapa (latitude 31° S, Coquimbo Region) in Chile. This is the southernmost record of the species within Chile and South America, extending its geographic range ca. 200 km southward. 1 Universidad de Chile, Facultad de Ciencias, Departamento de Ciencias Ecológicas, Casilla 653, Santiago, Chile. 2 Programa para la Conservación de los Murciélagos de Chile (PCMCh) ZP: 7780192 * Corresponding author. E-mail: sanpedro@ug.uchile.cl; ar.sanpedro@gmail.com Annia Rodríguez-San Pedro 1, 2*, Juan Luis Allendes 2, María L.C. Castillo 1, 2, Diego A. Peñaranda 1, 2 and Francisco T. Peña-Gómez 1, 2 Distribution extension and new record of Myotis atacamensis (Lataste, 1892) (Chiroptera: Vespertilionidae) in Chile DOI: 10.15560/10.5.1164 The Atacaman Myotis, Myotis atacamensis (Lataste, 1892), is a poorly known vespertilionid bat endemic to the central portion of the pacific coast of South America. It is found only in arid and semiarid environments, from western Peru to northern Chile (Simmons 2005; Iriarte 2008). Its type locality is San Pedro de Atacama, Antofagasta Region, northern Chile (Lataste 1892; LaVal 1973). Myotis atacamensis and the recently described Myotis diminutus Moratelli & Wilson, 2011, from Ecuador, are the smallest representatives of the genus Myotis in South America (Moratelli and Wilson 2011). Osgood (1943) and Cabrera (1958) considered Myotis atacamensis as a subspecies of Myotis chiloensis (Waterhouse, 1840), but LaVal (1973) treated atacamensis at the species level, which was followed by Wilson (2008). Studies based on molecular and morphological data support the separation of M. chiloensis and M. atacamensis, even suggesting a quite distant relationship between both species (Jones et al. 2002; Stadelman et al. 2007). In Chile, M. atacamensis differs from its congeners by its lighter fur color with dark bases and light tips, its shorter forearm length, and tiny skull (Wilson 2008; Díaz et al. 2011). This species feeds exclusively on insects that are captured in flight (Galaz et al. 2009). Foraging activity begins one hour before dusk and lasts for about three hours (Galaz et al. 2009). The distribution of M. atacamensis in Chile extends from Tarapacá region (Latitude 19° S), southward to the province of Elqui (Latitude 30° S), in the Coquimbo Region, where this species can be found in sympatry with M. chiloensis. In this latter region, M. atacamensis has also been associated with coastal areas and watercourses surrounded by xeric vegetation, where rock crevices are probably used as roots (Mann 1978; Iriarte 2008). However, the knowledge about the distribution of M. atacamensis is based mainly on information obtained from occasional or incidental collections, which probably might be due to the lack of bat studies in the country. Here we report the first record of M. atacamensis for the province of Choapa, Coquimbo Region, Chile. This is the southernmost record of the species within Chile and South America, extending its known geographic range in ca. 200 km southward from the last previous record at the Coquimbo Region (Tamayo and Frassinetti 1980). The record of the species was made during a bat survey in February 2013 at the Reserva Nacional Las Chinchillas 31°30′34.14′′ S, 71°06′23.92′′ W (Figure 1; Appendix 1) at 556 m of altitude. This Reserve is a protected area located 16 km N from the Comuna Illapel, Choapa province, Coquimbo Region, Chile. The climate of the study site is of a semiarid Mediterranean type, with most rainfall concentrated in the winter season (di Castri and Hajek 1976). The mean annual precipitation is about 185 mm, widely variable between years and alternating between long droughts and unusual years of high rainfall seemingly associated to El Niño events (di Castri and Hajek 1976; Jaksic 2001). The vegetation consists on thorny shrubs (Luebert and Pliscoff 2006) and succulent species (Medel 2000; Hoffmann and Walter 2004). Two adult females and two adult males of M. atacamensis were captured with a mist-net placed in the vicinity of the administrative offices of the park. The four individuals captured here were part of a colony with more than 30 individuals sheltering in the house roof at about 2.5 m above the ground level. The characters of the individuals captured are in agreement with those reported by Díaz et al. (2011), with general coloration pale ochraceous, and dorsal hairs with dark base and light tip. External measurements of the females captured are: body weight (g) 4.0, 4.0; total length (mm) 78, 76; forearm length (mm): 36.5, 34.0; wingspan (mm) 241, 250 (Figure 2). External measurements of males are: body weight (g) 5.0, 5.0; total length (mm) 77, 76; forearm length (mm) 37.0,

The Atacaman Myotis, Myotis atacamensis (Lataste, 1892), is a poorly known vespertilionid bat endemic to the central portion of the pacific coast of South America.It is found only in arid and semiarid environments, from western Peru to northern Chile (Simmons 2005;Iriarte 2008).Its type locality is San Pedro de Atacama, Antofagasta Region, northern Chile (Lataste 1892;LaVal 1973).Myotis atacamensis and the recently described Myotis diminutus Moratelli & Wilson, 2011, from Ecuador, are the smallest representatives of the genus Myotis in South America (Moratelli and Wilson 2011).Osgood (1943) and Cabrera (1958) considered Myotis atacamensis as a subspecies of Myotis chiloensis (Waterhouse, 1840), but LaVal (1973) treated atacamensis at the species level, which was followed by Wilson (2008).Studies based on molecular and morphological data support the separation of M. chiloensis and M. atacamensis, even suggesting a quite distant relationship between both species (Jones et al. 2002;Stadelman et al. 2007).In Chile, M. atacamensis differs from its congeners by its lighter fur color with dark bases and light tips, its shorter forearm length, and tiny skull (Wilson 2008;Díaz et al. 2011).This species feeds exclusively on insects that are captured in flight (Galaz et al. 2009).Foraging activity begins one hour before dusk and lasts for about three hours (Galaz et al. 2009).The distribution of M. atacamensis in Chile extends from Tarapacá region (Latitude 19° S), southward to the province of Elqui (Latitude 30° S), in the Coquimbo Region, where this species can be found in sympatry with M. chiloensis.In this latter region, M. atacamensis has also been associated with coastal areas and watercourses surrounded by xeric vegetation, where rock crevices are probably used as roots (Mann 1978;Iriarte 2008).However, the knowledge about the distribution of M. atacamensis is based mainly on information obtained from occasional or incidental collections, which probably might be due to the lack of bat studies in the country.Here we report the first record of M. atacamensis for the province of Choapa, Coquimbo Region, Chile.This is the southernmost record of the species within Chile and South America, extending its known geographic range in ca.200 km southward from the last previous record at the Coquimbo Region (Tamayo and Frassinetti 1980).
The record of the species was made during a bat survey in February 2013 at the Reserva Nacional Las Chinchillas 31°30′34.14″S, 71°06′23.92″W (Figure 1; Appendix 1) at 556 m of altitude.This Reserve is a protected area located 16 km N from the Comuna Illapel, Choapa province, Coquimbo Region, Chile.The climate of the study site is of a semiarid Mediterranean type, with most rainfall concentrated in the winter season (di Castri and Hajek 1976).The mean annual precipitation is about 185 mm, widely variable between years and alternating between long droughts and unusual years of high rainfall seemingly associated to El Niño events (di Castri and Hajek 1976;Jaksic 2001).The vegetation consists on thorny shrubs (Luebert and Pliscoff 2006) and succulent species (Medel 2000;Hoffmann and Walter 2004).
Two adult females and two adult males of M. atacamensis were captured with a mist-net placed in the vicinity of the administrative offices of the park.The four individuals captured here were part of a colony with more than 30 individuals sheltering in the house roof at about 2.5 m above the ground level.The characters of the individuals captured are in agreement with those reported by Díaz et al. (2011), with general coloration pale ochraceous, and dorsal hairs with dark base and light tip.External measurements of the females captured are: body weight (g) 4.0, 4.0; total length (mm) 78, 76; forearm length (mm): 36.5, 34.0; wingspan (mm) 241, 250 (Figure 2).External measurements of males are: body weight (g) 5.0, 5.0; total length (mm) 77, 76; forearm length (mm) 37.0,   Myotis atacamensis has been classified as Near Threatened by the IUCN (Barquez and Díaz 2008) because of its strong dependence on a habitat that has become severely fragmented.In Chile and Peru, however, the species has not been evaluated (CONAMA 2009;Pacheco et al. 2009).The new record presented herein is an important contribution to the knowledge of the geographic range of M. atacamensis, with some conservation implications for the species because it represents the addition of a second bat species for the Reserva Nacional Las Chinchillas, where only M. chiloensis had been reported to date (CONAF 1996).Therefore, we recommend the inclusion M. atacamensis into the conservation goals and management plan of this natural reserve.This finding also reaffirms the knowledge gaps on M. atacamensis and on Chilean bat species in general.Further studies on bat species inhabiting Chile are needed, not only to contribute to a better understanding of their geographic distribution, but also to improve our knowledge on their conservation status.

Figure 2 .
Figure 2. Female Myotis atacamensis captured close to a human building (reserve's administrative office) in the Reserva Las Chinchillas, Choapa province, Coquimbo Region, Chile.The white arrow indicates de contrasting bicolor pattern of the ventral fur, dark in the base and lighter in the tips, which gives the species a pale coloration.Photo: María L. C. Castillo.

Figure 1 .
Figure 1.Locality records of Myotis atacamensis in South America.Circles indicate historical records until the present study.The star indicates the new record, which represents the southernmost locality for the species.The shaded area shows the distribution according to the IUCN (2008).