Accepted by P. Passos: 18 Sept. 2014; published: 9 Oct. 2014 ZOOTAXA ISSN 1175-5326 (print edition) ISSN 1175-5334 (online edition) Copyright © 2014 Magnolia Press Zootaxa 3872 (3): 291–300 www.mapress.com/zootaxa/ Article 291 http://dx.doi.org/10.11646/zootaxa.3872.3.5 http://zoobank.org/urn:lsid:zoobank.org:pub:1B4717AE-9993-4166-BAA2-45DFC907080C Two new species of Atractus from Colombia (Reptilia, Squamata, Dipsadidae) GUNTHER KÖHLER 1,3 & MAX KIECKBUSCH 1,2 1 Senckenberg Forschungsinstitut und Naturmuseum, Senckenberganlage 25, 60325 Frankfurt a.M., Germany 2 Department of Animal Evolution and Systematics, Faculty of Biology, Philipps University Marburg, Karl-von-Frisch-Straße 8, 35043 Marburg, Germany. E-mail: Kieckbus@students.uni-marburg.de 3 Corresponding author. E-mail: gkoehler@senckenberg.de Abstract We describe two new species of Atractus from Colombia: one from the Serrania de la Lindosa, south of San José de Gua- viare in the province Guaviare, and another from Punta de Betin in the province Magdalena, close to the Caribbean coast. The first new species differs from all congeners by having a combination of 17 smooth dorsal scale rows; loreal present, approximately as long as high; temporals 1+2; seven supralabials; seven infralabials; five maxillary teeth; four gular scale rows; four pre-ventrals; 187 ventrals in single male; 29/31 subcaudals in single male; dorsum of body with longitudinal stripes; venter uniformly dark gray. The second new species differs from all congeners by having a combination of 17 smooth dorsal scale rows; loreal absent; temporals 1+2; seven supralabials; six or seven infralabials; eight maxillary teeth; three gular scale rows; three pre-ventrals; 146 ventrals in single male; 31/32 subcaudals in single male; dorsum of body and tail reddish brown with paired, occasionally slightly alternating lateral vertical cream blotches, approximately one dorsal scale broad, not contacting in vertebral region; venter cream with reddish brown blotches, forming two parallel se- ries on anterior body and a checkered pattern on the rest of body. Key words: Amazonia, Caribbean coast, external morphology, systematics, taxonomy Introduction The dipsadine genus Atractus Wagler 1828 constitutes the most diverse snake genus in the world with over 140 currently recognized species (Passos et al. 2013a). Although the genus is widely distributed, ranging from Panama to northeastern Argentina (Giraudo & Scrocchi 2000; Myers 2003), most of the species are endemic to small geographical ranges (Myers 2003; Passos et al. 2010; Prudente & Passos 2008; Passos et al. 2013c; Silva et al. 2005). The species of this genus inhabit different types of tropical forests, either primary or secondary, and there are even records of species in banana plantations or urban areas (Esqueda & La Marca 2005; Passos et al. 2007b). Snakes of the genus Atractus inhabit almost all South American biomes such as coastal lowland rain forest, premontane forest, gallery forest, cloud forest, cerrado savanna, riparian forest, and Amazonian lowland forest (Hoogmoed 1980; Martins & Oliveira 1998; Silva et al. 2005; Esqueda & La Marca 2005; Zaher et al. 2005; Passos et al. 2010). The altitudinal distribution of the species in this genus ranges from sea level up to 4,500 m above sea level (asl) (Passos et al. 2013a), while the highest diversity of Atractus species is found in the Colombian Andes (Passos et al. 2009b,d). The small to moderate-sized snakes of the genus show a rather secretive, semifossorial life style, being responsible for the relative scarcity of many Atractus species in collections (Schargel & García-Pérez 2002; Myers 2003; Myers & Donnelly 2008; Prudente & Passos 2010). Only a few species are known to exceed the length of one meter, with Atractus gigas Myers & Schargel 2006 and A. touzeti Schargel, Lamar, Passos, Valencia, Cisneros-Heredia, & Campbell 2013 being probably the largest species in the genus. Several species of Atractus have been described based on a single specimen or small series. Recent field work and revisions of museum holdings has yielded additional specimens of some of these species. Examples are A. dunni Savage 1955 (Cisneros-Heredia 2005), A. modestus Boulenger 1894 (Passos et al. 2007a), A. wagleri Prado 1945 (Passos & Arredondo 2009), A. bocki (Passos et al. 2009a), A. gigas Myers & Schargel 2006 (Passos et al.