NOTA

New records of Psomophis obtusus (Cope, 1863) (Serpentes: Dipsadidae) in Argentina and Uruguay

 

Diego O. Di Pietro¹, Santiago J. Nenda² & Jorge D. Williams³

¹ Sección Herpetología, División Zoología Vertebrados, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata. Paseo del Bosque s/n. CP B1900FWA, La Plata, Argentina. diego_dipietro@hotmail.com
² División Herpetología, Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" - CONICET. Ángel Gallardo 470. CP C1405DJR, Ciudad Autónoma de Buenos Aires, Argentina. santiagojnenda@yahoo.com.ar
³ Sección Herpetología, División Zoología Vertebrados, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata. Paseo del Bosque s/n. CP B1900FWA, La Plata, Argentina. williams@fcnym.unlp.edu.ar

Recibido: 13/10/10
Revisado: 29/11/10
Aceptado: 02/12/10

 

The snake genus Psomophis Myers and Cadle, 1994, currently in the Tribe Psomophiini (Zaher et al., 2009) comprises three species: P. genimaculatus (Boettger, 1885), P. joberti (Sauvage, 1884)and P. obtusus (Cope, 1863). These terrestrial dipsadids inhabit lowlands in South America east of the Andes, between parallels 0° (mouth of Amazon, Brazil) and 35°S, Río de la Plata, Uruguay (Myers and Cadle, 1994). Psomophis obtusus has the southernmost distribution of the genus, and was previously recorded for southern Brazil, southern Paraguay, Uruguay and adjacent northern Argentina (Peters and Orejas-Miranda, 1970; Lema, 1994; Myers and Cadle, 1994; Scrocchi and Giraudo, 1997; Achaval-Elena, 2001; Giraudo and Scrocchi, 2002).

In Argentina inhabits two species of the genus Psomophis: P. genimaculatus in Corrientes, Chaco, Formosa and Salta provinces (Scrocchi and Giraudo, 1997; Lions and Alvarez, 1997; Giraudo and Scrocchi, 2002; Nenda, 2007), and P. obtusus in Corrientes, Chaco, Entre Ríos, Formosa, Santa Fe, and northeastern Buenos Aires provinces(Freiberg, 1939; Yanosky, 1989; Cei, 1993; Myers and Cadle, 1994; Vuoto, 1995; Scrocchi and Giraudo, 1997; Giraudo and Scrocchi, 2002). In Uruguay, P. obtusus is widely distributed throughout the territory (Vaz-Ferreira et al., 1970; Myers and Cadle, 1994; Achaval-Elena, 2001), although the species was not reported in the departments of Colonia, Río Negro, and Salto (Carreira et al., 2005). Herein we report the southernmost locality of the genus Psomophis and a new department record of Psomophis obtusus in Uruguay.

We analyzed 23 specimens of P. obtusus deposited at the Herpetological Collections of the Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" (MACN), Centro Nacional de Investigaciones Iológicas (CENAI, housed at MACN), and Museo de La Plata (MLP); see Appendix for locality and collection details.

An adult female of Psomophis obtusus (MLP.JW 1799) was collected on November 2003 by Víctor E. Sansberro in Partido de Tandil (37° 20' S, 59° 07' W), Buenos Aires province, Argentina. The measures and scutellation characters of specimen MLP.JW 1799 are: 335 mm body length, 101 mm tail length, tail represents 23.16 percent of total length, pupil of eye round, dorsal scales in 19-19-17 rows, 178 ventrals, cloacal plate divided, 63 paired subcaudals, one preocular and two postoculars in each side, 1+2 temporals, eight supralabials, fourth and fifth entering the orbit, one loreal in contact with the second and third supralabials, ten infralabials in the right side, six of them in contact with geneials and nine infralabials in the left side, five of them in contact with geneials.

An adult female of P. obtusus (MACN 34477) was collected on 1987 by Guillermo Gnida in Colonia Lavalleja (31° 06' S, 57° 01' W), Salto department, Uruguay. The measures and scutellation of specimen MACN 34477 are: 320 mm body length, 106 mm tail length, tail represents 24.88 percent of total length, pupil of eye round, dorsal scales in 19-19-17 rows, 187 ventrals, cloacal plate divided, 71 paired subcaudals, one preocular and two postoculars in each side, 1+2 temporals, eight supralabials, fourth and fifth entering the orbit, one loreal in contact with the second and third supralabials, and ten infralabials, six of them in contact with geneials.

The locality of MLP.JW 1799 is situated ca. 320 km south from Partido de San Fernando, the previous records in northeastern Buenos Aires province, Argentina (Scrocchi and Giraudo, 1997), and ca. 460 km southwest from the southern known locality in Maldonado department, Uruguay (Carreira et al., 2005). This contribution provides information on the presence of Psomophis obtusus in hilly environments, a habitat not previously known for the species in Argentina, and reveals a gap in the distribution of the species between northeastern Buenos Aires populations and southern ones of Tandil hills.

ACKNOWLEDGMENTS

We are grateful to B. Blotto and M. Pereyra from the División de Herpetología MACN for his friendship and collaboration, to P. Cacivio, R. Cajade, and D. Barrasso for bringing us valuable specimens from Chaco. To V. Sansberro for additional information about the collected specimen. We are also grateful to J. Faivovich from the División de Herpetología MACN for laboratory support. To Comisión de Investigaciones Científicas de la provincia de Buenos Aires (CIC).

APPENDIX

Examined specimens of Psomophis obtusus: Argentina: Buenos Aires: MACN 2674, Bancalari, XI/1956; MACN 10255, San Fernando, II/1950; MACN 33550, Capilla del Señor, 1982; MLP.JW 1799, Tandil, XI/2003. Corrientes: MACN 13980, Concepción, Rincón de Luna, XI/1961; MACN 37772, Ituzaingó, Ruta Nac. N° 12 km 1114, 17/XII/2001; MACN 39798, 25 km S from Mercedes, Ea. El Remanso, 13/XI/1999; CENAI 1721, Monte Caseros, 19/XI/1964; MLP.R 5455, Colonia Carlos Pellegrini, Ea. Iberá, 19/XI/2009. Chaco: MLP.R 5445, Libertador General San Martín, Selvas del Río de Oro, 19/XI/2008. Entre Ríos: CENAI 2500, Federal, El Cimarrón, 31/I/1968; CENAI 2056, La Paz, Alcaraz, 2/XI/1966; MACN 34210, MACN 34211, Perdices, 29/XI/1986; MLP.R 5456, La Paz, Ruta Prov. N° 6, 10,6 km NE from Colonia Avigdor, 1/XI/2009; MLP.R 5457, La Paz, Ruta Prov. N° 6, 7,5 km E from Colonia Avigdor, 7/XI/2008; MLP.R 5502, La Paz, Ruta Prov. N° 6, 1,3 km W from Yeso, 1/XI/2009. Santa Fe: MACN 33549, Garay, 10 km W from Saladero Cabal, 24/II/1970; MACN 37404, Vera, 1951. Uruguay: MACN 1109, MACN 1110, Rocha, Castillos, 1899; MACN 34477, Salto, Colonia Lavalleja, 1987; CENAI 3071, Durazno, 1971.

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