New records of Pristidactylus nigroiugulus Cei , Scolaro & Videla , 2001 ( Squamata : Leiosauridae ) with a geographic distribution map

We provide new geographic records for Pristidactylus nigroiugulus Cei, Scolaro & Videla, 2001 from Argentina. We present the first record for Santa Cruz province and the southernmost records of the species based on lizards collected in the austral summers of 2012/2013 and 2013/2014. Based on a museum specimen, we extend the species distribution to the eastern part of the Somuncurá Plateau. An updated distributional map is included.

Leiosaurid lizards are widely distributed in South America from southern Amazonia to southern Patagonia, through the Cerrado, Atlantic Forest, Monte and Chaco biomes (Pough et al. 2015).These lizards are terrestrial, arboreal, or rock-dwelling, with a maximum size of 130 mm snout-vent length (SVL), and poorly studied in comparison to other iguanians.Within leiosaurids, Pristidactylus Fitzinger, 1843 is the genus having the most species, with ten recognized, but some of these have very small distributional ranges in the Córdoba and Ventana mountains, central and northern Patagonian steppes as well as in the pre-Andean ranges of western Argentina and central Chile.Pristidactylus nigroiugulus Cei, Scolaro & Videla 2001 (Figure 1) is the southernmost distributed species and has the largest geographic distribution of any Pristidactylus species.It was described from the foothills of Sierra Negra plateau in central Patagonia and is a medium-sized lizard (SVL = 100 mm) with a pronounced sexual dichromatism (Cei et al. 2001;Cei et al. 2004;Scolaro 2005).Originally, P. nigroiugulus was known only from a small number of occurrences in southern Río Negro province and northern and central areas of Chubut province (Cei et al. 2001;Avila et al. 2003), but later Minoli & Avila (2011) extended its geographic range to include the Chico river basin, centraleastern Chubut province.
In the austral summer of 2012/2013 we made a herpetofauna study on the oil fields of the Golfo San Jorge Management Unit of Pan American Energy (UG-GSJ).The     Avila et al. (2003) and Minoli and Avila (2011).Almost all records are specimens deposited at LJAMM-CNP collection and revised for this study.Red dots: new localities found in this study.Detailed information about all this records are included in the Appendix.Black lines are provincial limits.White dots: main towns, for reference.
Pristidactylus nigroiugulus differs from all other species of the genus by the male dorsal pattern that is green or brownish green, without lateral markings.The adult female dorsal pattern has transverse indented dark bands, often broken into regular bands of dark dots, and distinctive dark horseshoe-shaped marks across the head.Ventrally both sexes are whitish, but with a nearly triangular black spot on the throats of males (Cei et al. 2001).
Our new records, shown in Figure 2, extend significantly the known geographic distribution of P. nigroiugulus in southern and central Chubut.These records include the first from Sarmiento department, and add P. nigroiugulus to the herpetofauna of Santa Cruz province.Here, we extend the known distribution of this species by at least 120 km south and 80 km southeast from previous records in the upper Río Chico river valley region.The specimen from Río Negro province represents the species' easternmost known occurrence anywhere (80 km northeast from the type locality) and the first record in Valcheta department.All new occurrence record extended the species' distribution to the edges of the central Patagonian volcanic plateaus and related mountain ranges.Continuous new records of this species demonstrates how little is known about the lizard fauna of Patagonia.Vast regions still inadequately or unsurveyed.

Figure 2 .
Figure 2. Geographic distribution for Pristidactylus nigroiugulus in central Patagonia, and location within Argentina (inset).Green dots: previous bibliographic records for the species in Río Negro and Chubut provinces cited in Avila et al. (2003) andMinoli and Avila (2011).Almost all records are specimens deposited at LJAMM-CNP collection and revised for this study.Red dots: new localities found in this study.Detailed information about all this records are included in the Appendix.Black lines are provincial limits.White dots: main towns, for reference.

Table 1 .
Simmons 2002)|Pristidactylus nigroiugulus in the Patagonia, Argentina Specimens of Pristidactylus nigroiugulus studied in this work, including voucher numbers and geographic data.Site codes correspond to numbers on the map (Figure2).All lizards were collected by noose or hand, kept alive in plastic bottles, and transported to the lab.At each collection site we recorded latitude, longitude, and elevation by a Garmin® GPS receiver.Animals were euthanized at the laboratory by a pericardic injection of sodium thiopental Abbot® or Pentovet®, fixed in 20% formalin, and stored in 70% ethanol (standard herpetological procedures according toSimmons 2002).Tissue samples of liver and muscle were taken from collected animals.L. Elizalde donated a juvenile lizard from UG-GSJ collected in a pitfall trap for insects.Despite poor preservation, we identified the specimen as P. nigroiugulus.All specimens are stored at LJAMM-CNP collection that belongs to IPECC-Centro Nacional Patagónico (CENPAT-CONICET), Puerto Madryn, Argentina.All specimens studied are in Table1