A new giant Atractus (Serpentes: Dipsadidae) from Ecuador, with notes on some other large Amazonian congeners

Abstract

We describe a new species of Atractus from Cordillera de los Guacamayos in the Andes of Ecuador. This new species is the largest known species of Atractus, reaching almost 120 cm in total length with a robust habitus. We also use multivariate statistical analyses of morphometric data to look into the taxonomic confusion involving other large, banded/blotched, species of Atractus in Western Amazonia. We show that A. snethlageae has a widespread distribution in Amazonia and has been repeatedly confused with A. major in Ecuador owing to its color polymorphism. Our multivariate statistical analyses support previous suggestions to recognize A. snethlageae as a distinct species relative to A. flammigerus. Taxonomic accounts are provided for both A. major and A. snethlageae including detailed color pattern descriptions. We also find that there are no valid morphological differences to support recognizing A. arangoi as a separate species from A. major; consequently we synonymize the former name with the latter.

Molecular phylogeny of Atractus (Serpentes, Dipsadidae), with emphasis on Ecuadorian species and the description of three new taxa

“…The remaining individuals were detected by turning over logs, rocks and other surface objects. All specimens included in the genetic analyses were morphologically identified according to Savage (1955, 1960), Cisneros-Heredia (2005), Passos et al (2009a), Arteaga et al (2013), Schargel et al (2013) and Salazar-Valenzuela et al (2014). We generated sequence data for samples marked with an asterisk under Appendix I, which includes museum vouchers at the Museo de Zoología de la Universidad Tecnológica Indoamérica (MZUTI), the División de Herpetología del Museo Ecuatoriano de Ciencias Naturales (DHMECN) and the Fundación Herpetológica Gustavo Orcés (FHGO).…”

“…Most of these new species have been described using a combination of meristic and morphometric characters (Passos et al 2009a, 2016, Passos and Lynch 2010, Schargel et al 2013, Salazar-Valenzuela et al 2014). However, with the exception of the preliminary phylogeny presented in De Oliveira and Hernández-Ruz (2016), no studies have involved a phylogenetic approach to test species arrangements and boundaries.…”

Redescription ofAtractus punctiventrisand Description of Two NewAtractus(Serpentes: Dipsadidae) from Brazilian Amazonia

“…The specimens examined and identified as A. badius by Savage (1960) refer to other banded-blotched Amazonian species of Atractus with 17 dorsal scale rows (e.g., A. flammigerus, A. schach, and A. snethlageae; see Schargel et al 2013). Considering the old and new discoveries, the A. badius group at the moment only contains the nominal species and A. major, after Passos et al (2009e) assigned Atractus multicinctus to its own group.…”

“…Atractus is the most species-rich snake genus in the world, with more than 140 valid species at present (Passos et al 2013a;Salazar-Valenzuela et al 2014). The genus, as currently understood, represents one of the most morphologically diverse radiations of New World snakes, having adult body size from 100 mm (Passos et al 2013b) to more than 1 m (Schargel et al 2013), and a color pattern varying from uniformly colored, banded, or striped (Savage 1960) to putative coralsnake mimetic patterns (Martins and Oliveira 1993;Almeida et al 2014). Despite renewed interest in the systematics of Atractus in the last 10 yr, the taxonomy of this genus remains in a state of flux with frequent resurrections (Passos et al 2010a), rediscoveries , synonymizations (Passos et al 2013a), and descriptions of new species (Salazar-Valenzuela et al 2014).…”

“…Notwithstanding, even some recent studies have been unable to propose realistic diagnoses and provide detailed comparisons in the descriptions of putative new species of Atractus (e.g., Esqueda 2011). On the other hand, some authors have emphasized that taxonomic studies on Atractus must follow an explicit comparative framework comprising the related type series (Passos et al 2013a) and, when available, representative samples analyzed through rigorous hypothesis testing (Passos et al 2010a,b;Schargel et al 2013). Amaral (1933) described Atractus punctiventris based on a single specimen with 15 dorsal scale rows from Villavicencio on the piedmont of the eastern Cordillera of Colombia (¼ Sabana province from Morrone 2014).…”