New record of Boa constrictor occidentalis Philippi , 1873 ( Serpentes : Boidae ) in San Juan province , Argentina

We document the first record of Boa constrictor in Valle Fértil department, San Juan province, Argentina. The specimen was collected and deposited in the herpetological collection of the Department of Biology, Universidad Nacional San Juan. This record extends the known distribution for this species in San Juan province by 105 km.


INTRODUCTION
The genus Boa is represented only by one species, Boa constrictor (Vences et al. 2001).This is one of the largest and most widely distributed snakes in America, showing great plasticity in the occupation of different ecosystems.Its distribution extends from northern Mexico to central Argentina, except Chile and Uruguay.It inhabits rainforests, savannas, forests and semidesert scrub of most tropical and subtropical areas of the continent.Because of its wide distribution, morphological variability and the lack of taxonomic and systematic studies (Scrocchi, pers. comm.), several subspecies have been named (Langhammer 1983;Peters and Orejas-Miranda 1986;Price and Russo 1991).Boa constrictor occidentalis is the southernmost subspecies (Bertona and Charaviglio 2003).
Boa constrictor occidentalis is associated with burrows of vizcachas (Lagostomus maximus), for both prey and refuge (Cei 1993;Sironi et al. 2000).Males and females reach sexual maturity at an average snout-vent length (SVL) of 149 cm and 164 cm, respectively (Chiaraviglio et al. 2001).The species is subject to strong human pressures for skins and the pet trade (Ávila and Acosta 1996), and its habitat is being severely modified by intense farming and cattle raising in Argentina.As a consequence, it is considered a threatened species (Giraudo et al. 2012;Acosta et al. in press) and has been included in Appendix I of CITES (2014).
The systematic listing of Argentine snakes (Giraudo and Scrocchi 2002) shows B. c. occidentalis occurring in 13 provinces: Chaco, Formosa, Salta, Jujuy, Tucumán, Santiago del Estero, Santa Fe, La Rioja, Catamarca, Córdoba, San Juan, San Luis and Mendoza.It is distributed mainly in the ecoregions of Chaco Oriental, Occidental and Serrano, and the northwest of Espinal (Di Fonzo de Ábalos and Bucher 1981;Reati 1996;Chiaraviglio et al. 1998).In San Juan province, existing data are scarce and mostly anecdotal.In this note we confirm the presence of B. c. occidentalis in Valle Fértil department of San Juan province, constituting the first record with voucher for this department.Precise information on its distribution is also provided.
The individual was identified as B. c. occidentalis by morphological comparisons with reference material in the herpetological collection of UNSJ, and verified by Juan Carlos Acosta.
In Argentina, the distribution of B. c. occidentalis has not been studied in detail.However, there are several studies that have contributed information about its range.Boa constrictor occidentalis has been reported in provinces of Chaco (Kacoliris 2006;Alvarez et al. 2009), Formosa (Lions et al. 1997;Alvarez et al. 2009), Santa Fé (Arzamendia and Giraudo 2002;Bosisio and Trucco 2002), Córdoba (Di Fonzo de Ábalos and Bucher 1981; Chiaraviglio et al. 1998;Briguera et al. 2005;Pelegrin et al. 2006), San Luis (Jackson 1986, Ávila andCarrizo 2003;Guerreiro et al. 2005), Salta (Cruz et al. 1992;Lavilla et al. 1995), Mendoza (Cei and Roig 1973), The site reported in this note is in the Chaco Occidental ecoregion, which is consistent with previous reports (Di Fonzo de Ábalos and Bucher 1981;Reati 1996;Chiaraviglio et al. 1998;Acosta et al. 2000;Laspiur et al. 2010) Specimens of B. c. occidentalis are rare in herpetological collections, making it difficult to determine its precise distribution (Acosta and Ávila 2001).Previous records of the subspecies in Valle Fértil are anecdotal (Cei and Castro 1978).Here we confirm for the first time for Tucumán (Laurent and Terán 1981), and San Juan (Ávila et al. 1998;Acosta and Ávila 2001;Laspiur et al. 2010).Giraudo and Scrocchi (2002) also included it in La Rioja, Santiago del Estero, Jujuy, and Catamarca.Recent studies have attempted to represent its distribution in Argentina based on observational records according to several environmental factors (Di Cola et al. 2008), and through surveys (Waller et al. 2010) (Figure 2).

Check
List 11(5): 1775, 25 October 2015 doi: http://dx.doi.org/10.15560/11.5.1775ISSN 1809-127X © 2015 Check List and Authors Notes oN GeoGraphic DistributioN Martínez T.A. et al. | New record of Boa constrictor occidentalis in San Juan an adult in the Sierra de Guayaguas, 25 de Mayo department, the most recent record for the province.
. Our record extends the distribution in San Juan 105 km north, in the eastern part of the province.It also extends its distribution area in Argentina 121 km farther west from the range predicted by Di Cola et al. (2008) and 8 km west of that predicted by Waller et al. (2010) (Figure 2).
, report it from Sierra Guayaguas and Pampa del Gigantillo, 25 de Mayo department, and also Valle Fértil department, but without voucher material.The presence of B. constrictor occidentalis in the province was confirmed, with reference material, in Caucete department, in the southeastern part of the province (Acosta and Avila 2001).Laspiur et al. (2010) observed

Figure 2 .
Figure 2. Distribution of Boa constrictor occidentalis in Argentina.Green Area: Distribution area according to Di Cola et al. (2008).Grey Area: Distribution area according to Waller et al. (2010).Light Grey: Absence area according to Waller et al. (2010).Square: individual registered in Caucete department by Acosta and Ávila (2001).Triangle: individual registered by Laspiur et al. (2010) in 25 de Mayo department.Star: New record that confirms the presence of the subspecies in Valle Fértil department.