First record of Eptesicus brasiliensis argentinus Thomas , 1920 ( Chiroptera , Vespertilionidae ) in Entre Ríos province , Argentina

Here, we present the first record of Eptesicus brasiliensis argentinus Thomas, 1920 for the province of Entre Ríos, Argentina. This subspecies was originally described as a full species (E. argentinus) based on its morphological features that clearly separate it from all other species of the genus. However, it was later treated as a subspecies of E. brasiliensis by Cabrera (1957), a treatment that was followed by all authors until today. Our record raises the number of bat species for the province of Entre Ríos to 21. This locality represents the fourth record for this subspecies in Argentina, after 35 years since the last known record was obtained. Its geographic range is extended by approximately 130 km to the south, which represents the southernmost known record for this subspecies, and a new ecoregion, the Espinal, is added to its distribution.


Methods
An intensive examination of specimens deposited at the CML (Colección Mamíferos Lillo), National University of Tucumán, Argentina, has allowed us to find specimens of Eptesicus brasiliensis argentinus, which represent a new locality for the distribution of the species, and the first report for the province of Entre Rios.
The specimens were collected with mist nets of different sizes, placed randomly in different microhabitats, mainly inside, or on borders of vegetation, and over streams.Specimens were originally fixed in formaldehyde 10% and preserved in alcohol 70%, and posteriorly prepared as skins, skulls and skeletons and deposited at the Colección Mamíferos Lillo (CML), Tucumán, Argentina.
The identification of the species was made using identification keys published by Barquez et al. (1999) and Díaz et al. (2016) as well as by comparison with specimens of several species of the genus deposited at the CML and other collections (see Appendix).
The locality of collection belongs to the Espinal ecoregion, which is characterized by low and xerophilous forests, where 93 endemic species were listed, among them, Prosopis caldenia Burkart, 1939 (Fabaceae), Condalia microphylla Cav.1799 (Rhamnaceae), Senecio subulatus D. Don ex Hook.and Arn.(Asteraceae), Gaillardia megapotamica (Spreng.)Baker (Asteraceae) (Matteucci 2012).The dominant landscape varies from flat plains to soft undulated land and to a lesser extent, low mountainous areas, with loessic and sandy soils (Matteucci 2012).Most of the Espinal is located on land with high agricultural and urban development, especially in the province of Entre Ríos, where deforestation has recently been intensified by the rapid expansion of soybean crops and eucalyptus plantations (Arturi 2006).The collection area is a patch of natural vegetation, surrounded by crops.
Identification.The specimens were identified by comparing external and cranial characters with specimens at the CML and descriptions published by Barquez et al. (1999) and Díaz et al. (2016).The most distinguishing characters, which led us to recognize our specimens as E. b. argentinus were the combination of large size and pale dorsal coloration of the specimens, besides the short dorsal hairs (ca 8 mm), forearms greater than 41 mm and the measurements of the skull (Table 1).

Discussion
The Argentine population of this species corresponds to the subspecies Eptesicus brasiliensis argentinus Thomas, 1920 which is characterized by its dorsal light brown  coloration with reddish tones, with hairs dark at the bases but with light tips; the slight contrast between dorsal and ventral coloration is also notable.Eptesicus b. argentinus cohabits in Argentina with 2 other species of the genus and differs from them mainly by size (Table 1), being the largest species with a forearm greater than 41 mm, while in E. furinalis is less than 41 mm and in E. diminutus is less than 37 mm.A fourth species occurring in Argentina, E. chiriquinus, is similar in size to E. b. argentinus, but both are morphologically quite different and their distri-  Gardner (2008) arbitrarily, without taxonomic or any other explanation, decided to place this subspecies as a synonym of Eptesicus b. arge (Cope, 1889) despite the significant differences of the 2 taxa, according to the original descriptions of both, E. argentinus and Vesperus arge Cope, 1889.It should be noted that when Vesperus arge was described, no holotype was designated nor specimen (or specimens) examined were indicated, so the existence of comparative or reference material for that species is not known.The short written description of this species is so general and superficial that no diagnostic characters can be found, and no forearm or cranial measurements were given, making comparisons with the species described by Thomas (1920) impossible, which is quite complete in this sense.
Furthermore, the few data indicated by Cope (1889) rule out the possibility that these forms can be interpreted as equals, starting with color description, which are strongly different and already separates the 2 species since V. arge was described as a dark brown species, and E. argentinus was remarked as very pale ("the palest of all known species of the genus", as remarked by Thomas 1920).In general, the most significant difference between the 2 species is the general coloration; E. argentinus is light brown whereas E. arge is dark brown.Barquez et al. (2009) suggested that V. arge is significantly different from E. argentinus, reinforcing the idea of E. argentinus as a full species as originally described by Thomas (1920).
This new locality extends the distribution of this species by approximately 130 km to south, representing the southernmost known record for E. b. argentinus.Davis and Gardner (2008) mentioned a record from Montevideo (Uruguay), without any citation, and according to the last comprehensive studies carried out in that country, this species is not in Uruguay (Botto et al. 2008, Rodales 2009), but instead all previous mentions of E. brasiliensis in that country belong to E. furinalis.We add here a new ecoregion, the Espinal, to the habitat preferences of the species, which until now had only been recorded in the Humid Chaco, and Delta and Islands of the Paraná river system.The locality "Estancia El Pilar, 2 km de Parada Tataré", indicated by Barquez et al. (1999) as "not located", is now located in this study and also belongs to the Espinal ecoregion (Fig. 1).
The type specimen and all the eight specimens of the type series of E. argentinus, were collected back in 1895 and the next record for the species, from Chaco province, was obtained in 1974.No information for this species has been cited after that so our specimens from Entre Ríos, represent the first record obtained after 35 years since the last known information about the distribution of this species.
The lack of surveys and the fact that the Province of Entre Rios has suffered great deterioration in its natural vegetation are some of the reasons that may explain the current scarcity and absence of records of this and other species of bats in the province.For example, if we compare the number of species of bats registered in Entre Ríos with the number of species from a neighboring province such as Corrientes, the latter has 30 species listed which is 9 more than Entre Ríos (Barquez and Díaz 2009, Barquez et al. 2011, Pavé and Giraudo 2014).

Figure 2 .
Figure 2. Eptesicus brasiliensis argentinus skin.Dorsal and ventral views of the skin of specimen CML 11965 of E. b. argentinus.
butions do not overlap.Eptesicus chiriquinus has long dorsal fur (10-12 mm) and the skull has well developed sagittal and lambdoidal crests, while E. b. argentinus has short dorsal hairs (ca 8 mm) and much less developed crests (Figs 2, 3).Eptesicus b. argentinus is known only from Argentina and it was described by Thomas (1920) as Eptesicus argentinus, from Goya, Corrientes Province.It was later placed under synonymy of E. brasiliensis by Cabrera (1957) as E. b. argentinus.More recently, Davis and

Figure 3 .
Figure 3. Eptesicus brasiliensis argentinus skull and mandible.Dorsal, ventral and lateral views of the skull and lateral view of the mandible of the specimen CML 11965 of E. b. argentinus.

Table 1 .
Barquez et al. 1999) measurements in mm (followingBarquez et al. 1999)of the specimens of Eptesicus brasiliensis argentinus included in this study (CML), compared with the holotype and paratypes in the Natural History Museum, London (BMNH).