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INTRODUCTION
Myotis Kaup, 1829 is one of the most complex and diverse genus among bats in the Neotropical Region. The previous difficulties to adequately identify the species of Argentina were mainly due to the small number of records collected throughout history in the country (Cabrera, 1930, 1958; Barquez, 1987; Barquez et al., 1999), which prevented the development of appropriate comparisons. However, the important development of further studies, has allowed the addition of sufficient information, both geographical and descriptive, and more elements facilitating to clarify the identity of species that were previously ambiguous. Barquez et al. (1999) included nine species of Myotis in Argentina, elevating this number to ten (Barquez, 2006) after recognizing Myotis dinellii as a full species as originally proposed by Thomas (1902). Recent investigations, basically developed by Moratelli et al. (2011, 2013) and Moratelli & Wilson (2011, 2014) are strongly impacting on the knowledge of the Neotropical species, so that the recognized number for the region is growing rapidly regarding the lists that emerged from reviews of the genus like those of Cabrera (1958), La Val (1973), or other more general articles as Simmons (2005) and Wilson (2008).
Wilson (2008) cited 12 species of Myotis for South America, seven of which are endemic, but including M. dinellii as a subspecies of M. levis, without paying attention to the previous opinion published by Barquez (2006).
The recent descriptions of five species (M. diminutus, M. handleyi, M. izecksohni, M. lavali, and M. midastactus), plus the revalidation of Myotis caucensis (Moratelli et al., 2011, 2013; Moratelli & Wilson, 2011, 2014) and the proposal for giving specific validity to M. pilosatibialis (Mantilla-Meluk & Muñoz Garay, 2014) elevate to 20 the number of currently recognized species of the genus in South America.
None of the traditional reviews (Miller & Allen, 1928; La Val, 1973) has included enough material from Argentina to allow, in those days, to convincingly clarify the identity of several of the species. Similarly, the traditional catalog of Cabrera (1958) includes a list of species that usually does not indicate the repositories of the specimens examined, but only refers to bibliographical sources and personal interpretation of the author. After an exhaustive review of specimens in systematic collections and its re-identification, along with many field sampling throughout the country (Barquez, 1987; Barquez et al., 1999), a fundamental rearrangement of the species in Argentina was reached, allowing to more precisely defining the diagnostics characters and a refinement of their geographical distributions.
Until now 10 species of Myotis have been cited for Argentina (Barquez, 2006; Barquez & Díaz, 2009; Díaz et al., 2011), most of them known only from a few records, leaving gaps along their general distributional areas. Therefore, it is not surprising to add new localities to the distribution of all species because many of them, as well as large territorial areas, have been effectively sub-sampled or have not been studied.
In this way, sampling in these regions enables the addition of more information, and also contributes to the knowledge of the populations, geographical, and ecological variations of the involved species. For the same reasons, the addition of new species to the Argentine territory is greater to the extent that the fieldwork, and the study of specimens in systematic collections, also increase.
In the context of extensive surveys conducted in northern Argentina, in the provinces of Salta and Misiones, we had the opportunity to collect two species that did not correspond, in their morphological and cranial characters, with any of the known species for the country, Myotis izecksohni and Myotis lavali which, in addition to the inclusion in the fauna of Argentina, they represent an extensive expansion of their known distributions.
MATERIAL AND METHODS
The specimens were obtained in two localities, in the provinces of Salta and Misiones, Argentina (Fig. 1). They were prepared as skin, skull and skeletons following Díaz et al. (1998) and deposited at the CML (Colección Mamíferos Lillo), University of Tucumán, Argentina. The following measurements were taken using digital calipers to the nearest 0.1 mm (Tables 1, 2) as described by Barquez et al. (1999), and Moratelli et al. (2011) for comparative purposes: ear length, forearm length, body weight, greatest length of skull, condylo-incisive length, mastoid breadth, braincase breadth, interorbital breadth, postorbital breadth, zygomatic breadth, breadth across canines, breadth across molars, maxillary toothrow length, mandibular length, and mandibular toothrow length. The length of the dorsal hairs was taken from the base to the tip of the hairs measured between scapulas.
FIGURE 1 New localities in Argentina for (1) M. lavali (Finca Alto Verde, Salta Province), and (2) M. izecksohni (Parque Provincial de la Sierra “Ing. Agrónomo Martínez-Crovetto”, Misiones Province).
TABLE 1 Measurements of the Holotype and a female Paratype of M. izecksohni from Moratelli et al. (2011), and two specimens from Misiones, Argentina. All measurements are expressed in mm, and weight is expressed in grams; *measurements taken from the dry skins.
| Myotis izecksohni Brazil | Myotis izecksohni Argentina | |||
|---|---|---|---|---|
| Holotype | Paratype | CML 10200 | CML 10201 | |
| Ear length | 12.5 | 12.7 | 12,17* | 11,4* |
| Forearm length | 38.3 | 36.3 | 37.8 | 36.52 |
| Greatest length of skull | 14.58 | 14.64 | 14.55 | 13.57 |
| Condylo-incisive length | 13.70 | 13.71 | 13.85 | 12.93 |
| Mastoid breadth | 7.06 | 7.05 | 7.04 | 6.96 |
| Braincase breadth | 6.79 | 6.61 | 6.82 | 6.60 |
| Interorbital breadth | 4.40 | 4.52 | 4.52 | 4.45 |
| Postorbital breadth | 3.51 | 3.43 | 3.5 | 3.42 |
| Zygomatic breadth | - | - | 8.76 | 8.35 |
| Breadth across canines | 3.52 | 3.74 | 3.71 | 3.43 |
| Breadth across molars | 5.60 | 5.81 | 5.74 | 5.34 |
| Maxillary toothrow length | 5.47 | 5.41 | 5.48 | 5.02 |
| Mandibular length | 10.13 | 10.21 | 10.56 | 9.82 |
| Mandibular toothrow length | 5.80 | 5.80 | 5.75 | 5.33 |
TABLE 2 Measurements of the Holotype of M. lavali (Moratelli et al., 2011) and range of female specimens from the paratype series from Brazil, compared with the two specimens from Argentina. All measurements are expressed in mm, and weight is expressed in grams.
| M. lavali Brazil | M. lavali Argentina | |||
|---|---|---|---|---|
| Holotype | Range of females | CML 7622 | CML 7623 | |
| Ear length | 13.0 | 11-14 | 14 | 15 |
| Forearm length | 34.4 | 32-36 | 36 | 36 |
| Body weight | 4.5 | 4-8 | 5 | 5 |
| Greatest length of skull | 13.98 | 13.4-14.3 | 13.1 | 13.4 |
| Condylo-incisive length | 13.41 | 12.8-13.6 | 13.3 | 12.7 |
| Mastoid breadth | 7.04 | 6.7-7.1 | 7.2 | 6.9 |
| Braincase breadth | 6.38 | 6.2-6.6 | 6.2 | 6.4 |
| Interorbital breadth | 4.61 | 4.2-4.8 | 5 | 4.8 |
| Postorbital breadth | 3.32 | 3.2-3.5 | 3.5 | 3.6 |
| Zygomatic breadth | 8.46 | 8.5-8.7 | - | - |
| Breadth across canines | 3.49 | 3.2-3.7 | 3.7 | 3.5 |
| Breadth across molars | 5.46 | 5.1-5.7 | 5.6 | 5.8 |
| Maxillary toothrow length | 5.30 | 5.0-5.4 | 5.1 | 5.4 |
| Mandibular length | 10.03 | 9.4-10.1 | - | - |
| Mandibular toothrow length | 5.73 | 5.4-5.8 | 5.6 | 5.6 |
The study area in Salta Province is located in the Yungas Ecoregion, a forested region that is part of the Amazon Domain of the Neotropical Region (Cabrera, 1971, 1976; Cabrera & Willink, 1980). In Argentina, this ecoregion is located between 22° and 28.5° south latitude, and is not a continuous unit but exists in fragments. The whole region has been significantly modified by human activity. In its natural state, penetrations of other phytogeographical units take place, especially those of Chacoan origin. The ecosystem, as it exists in Argentina, is considered to be threatened (Prado, 1995) principally due to the lack of control of human actions.
In Misiones, the samples were taken as part of a study developed about diversity of bats of the Fields and Weedlands Ecoregion (Burkart et al., 1999), which is a relatively small area located in part of southern Misiones and northern Corrientes, and characterized by the presence of grass savannas, alternating with patches of scrub and forests, constituting a complex ecotone between the Chacoan and Paranaense Phytogeographical Provinces.
RESULTS
As a result we have obtained samples of two species of Myotis, recently described from Brazil, but new to Argentina, whose inclusion in the country extends significantly their known distributions; both are included in new environments where these species were not previously known.
Family Vespertilionidae Myotis izecksohniMoratelli, Peracchi, Dias and de Oliveira, 2011
Specimens examined (2): Argentina, Misiones Province: Parque Provincial de la Sierra “Ing. Agrónomo Martínez-Crovetto”, Municipio de San José, Apóstoles Department, (27°44’39.49”S, 55°33’56.40”W), 210 m (Fig. 1), two females (CML 10200 and 10201) collected on 28 April 2010, by Fabricio M. Idoeta.
This species was recently described by Moratelli et al. (2011), based on specimens from Fazenda Maria Brandina, Reserva Biológica do Tinguá, Rio de Janeiro State, Brazil, 760 m altitude. The holotype and paratypes were previously cited as M. levis by Dias & Perachi (2008); also some additional specimens were previously cited as M. nigricans from Río de Janeiro (see Moratelli et al., 2011) and from Paraná (Arnone & Passos, 2007). All the original records are from the Atlantic Rainforest of south and southeastern Brazil. In 2015, the distribution of this species was extended to three localities of the State of Minas Gerais, also in southeastern Brazil in a region classified as a transition between the Atlantic Forest and Cerrado, with vegetation characteristics of the two biomes (Dias et al., 2015).
Description and comparisons
During our studies, carried out in April 2010, we captured in the province of Misiones, Argentina, two females of a species of Myotis that did not correspond to any of the known species of Argentina.
Shortly after our captures, when the description of Myotis izecksohni was published, we understood that our specimens (Fig. 2) corresponded exactly with the characteristics of the new species and their morphometry (see Table 1): forearm medium to large for South American species, long and silky fur (6.7 and 7.7 mm in specimens from Argentina), dorsal fur bicolor with dark bases and dark-brown to medium-brown tips, with bases and tips slightly contrasting; bicoloration is more evident in ventral fur, with hairs with very dark bases and light brown tips.
FIGURE 2 Dorsal (right) and ventral (left) view of Myotis izecksohni (CML 10200) from, Parque Provincial de la Sierra “Ing. Agrónomo Martínez-Crovetto”, Misiones, Argentina. Scale: 10 mm.
The wing membranes are dark brown; there is no fringe of hairs along the trailing edge of the uropatagium and the plagiopatagium is attached to the feet at the level of the toes.
The skulls of our specimens are as described in Moratelli et al. (2011) and comparatively large with respect to other Myotis species in Argentina, long and flat with a rounded supraorbital region; the sagittal crest is low, poorly marked and almost not evident; premolars aligned to the toothrow, and P2 is not crowded to the lingual side and clearly visible in lateral view; external measurements of the Argentine specimens, compared with those provided by Moratelli et al. (2011), are shown in Table 1.
The geographical area where Myotis izecksohni was collected in the province of Misiones is also inhabited by other six Myotis species with which it can be confused (M. albescens, M. levis, M. nigricans, M. riparius, M. ruber, and M. simus), but their differential characteristics (Díaz et al., 2016) allow to separate them easily: Myotis albescens is easily differentiable from this species by its frosted dorsal coloration, dark membranes rather than pale membranes, by the typical white abdominal and perianal area, the whitish band of the trailing edge of the uropatagium, and by its large and rounded feet. The species with which it can more easily be confused, by their similar size, is M. levis, but this has strikingly bicolored dorsal hairs, shorter dorsal hairs, and a fringe of hairs, although slightly visible, on the edge the tail membrane. It can be distinguished from M. nigricans by its markedly larger body size and by the bicolored dorsal hairs, which are almost unicolor in M. nigricans. From M. riparius can be distinguished by its larger size, dark coloration, long fur, and the absence of a sagittal crest in the skull. Although Myotis ruber is a species with long dorsal hairs, and similar in size to Myotis izecksohni, its strong red coloration separates them easily. It differs from Myotis simus because this has a very short and velvety fur, its coloration is bright orange-yellowish and the plagiopatagium is attached to the ankle and not to the toes.
Distribution and general comments
The collecting site is located within the “Fields and Weedlands” ecoregion (Martínez-Crovetto, 1963; Burkart et al., 1999) originally classified as a district of the Paranean Phytogeografic Province, an environment that was not cited for this species in previous publications (Moratelli et al., 2011; Dias et al., 2015). Our specimens were collected in a mist-net placed over a stream surrounded by dense vegetation of forests.
As Moratelli et al. (2011) indicated that they expected that this new species could be extended further south, including Uruguay; our samples confirms that prediction and expand the distribution of this species for about 650 km to the southwest of the currently known limits. This is also the first citation of this species out of Brazil.
Myotis lavali Moratelli, Peracchi, Dias, and de Oliveira, 2011
Specimens examined (2): Argentina, Salta Province: Finca Alto Verde, aproximadamente 20 km SW Orán, Orán Department (23°13’S, 64°32’W), 670 m (Fig. 1), two females (CML 7622 and 7623) collected on September 14, 2006, by Daniela Miotti.
This species was recently described by Moratelli et al. (2011), through an holotype and 29 paratypes, found deposited in systematic collections, from three localities in northeastern Brazil. Most of these localities are situated in the northeastern Brazilian Caatinga ecosystem, with the exception of one, but all are from sub-humid and deciduous forest formations, with distinctive lower temperatures compared with other adjacent localities in lower altitudes (Moratelli et al., 2011). Later Moratelli & Wilson (2013) added new distributional records for the Alto Chaco in Paraguay and for the Atlantic Forest of Brazil and Paraguay, extending the distribution of this species for about 2,000 km southwest and 400 km east.
In September 2006, we have captured at the Finca Alto Verde, a series of 15 specimens of Myotis of which two (CML 7622, 7623) were very different from the rest by their reddish brown coloration, and we have not been able to identify them as belonging to any of the known species of the genus. Our first impression, based on coloration, that this could be a geographical variation of M. ruber, was discarded in the laboratory because of the cranial morphology, distinctly smaller body size and general measurements of the specimens. These specimens were kept at the CML identified as Myotis sp. until Myotis lavali was described by Moratelli et al. (2011); then, when we compared our specimens with the new species, we found that all the diagnostic characters matched perfectly with those of our sample.
Description and comparisons
This is a small to medium species of Myotis with a forearm of 31.5 to 37 mm, long and silky fur, length of dorsal hairs 6 to 7 mm. Dorsal coloration strongly bicolor, hairs with dark brown bases and light-brown tips, ventral fur strongly bicolor with dark brown bases and cinnamon-buff tips (Fig. 3). Other characters of this species are the absence of a fringe of hairs in the trailing edge of the uropatagium, plagiopatagium attached to the toes, sagittal crest present, and second upper premolar not displaced to the lingual side, but generally aligned in the toothrow.
FIGURE 3 Dorsal (right) and ventral (left) view of Myotis lavali (CML 7623) from Finca Alto Verde, Salta, Argentina. Scale: 10 mm.
Coloration, morphometry, and skin and skulls characters (Table 2) of the specimens from Salta coincide exactly with the characters described for M. lavali in Moratelli et al. (2011).
In the current area of distribution of M. lavali in Argentina, other five species of the genus can be also found (Barquez, 2006; Barquez & Díaz, 2009). It cannot be confused with M. albescens because this has a strongly frosted dorsal pelage, a light colored venter, almost pure white on the abdomen and perianum and sides of the body, and pale wings membranes. From M. dinelli can be differentiated by the more reddish coloration, while M. dinelli is more yellowish and the edge of the uropatagium is whitish and have a fringe of hairs, although not very evident, and the face is very dark, almost black. Differentiation with M. keaysi is simple because this is clearly bigger, with the forearm more than 40 mm, general coloration dark and dorsal side of uropatagium covered by hairs that overpass the knees. Myotis nigricans is similar in size but the fur is shorter, their general coloration is much darker, not reddish, and dorsal hairs are almost unicolor or slightly bicolor but never as well differentiated as in M. lavali, and the sagittal crest is always absent. Finally, M. riparius is also similar in size (forearm 34.2-36.0 mm) but both can be differentiated because the dorsum of M. riparius have some hairs with yellowish tips giving this species a slight frosted appearance, and also has a small P2 that is displaced to the lingual side of the toothrow.
Distribution and general comments
The new records extend the distribution of this species, approximately 360 km to the southwest, to the province of Salta, in Argentina. Previous records are from localities of the Caatinga and Atlantic Forest of Brazil and the Alto Chaco of Paraguay. Our specimens add the Yungas which, like the Atlantic Forest, is a forest ecoregion, different from the xeric vegetation known so far for the distribution of this species.
The only two specimens collected were adult females, probably nulliparous according to the condition of their mammae, which were small, whitish, and covered by hairs.
It is remarkable how the descriptions of new species of Myotis have increased in recent years, as well as changes in the taxonomic status of several subspecies, that makes clear the importance and value of studying the museum collections to enlighten several aspects of systematics, distribution, and natural history of a fauna in need of urgent measures that favor their preservation. Also, the new investigations are favoring the scientific knowledge of the genus so allowing to improve our understanding of the evolutionary history of the group in South America.
