Abstract Atractus badius has a long and controversial nomenclatural history due to both its antiquity and the brevity of its original description. This species was described based on two syntypes from Java. Later, a lectotype was designated and the distribution range restricted to the Guiana Shield. Although this species has been repeatedly recorded throughout Amazonia and the Andes, these records have been erroneously assigned to A. badius because of a considerable level of confusion in the literature. We found 13 additional specimens of this poorly known snake, expanding our knowledge on its morphological variability, phylogenetic relationships and distribution. In this paper, we report new localities and data on meristic, morphometric, coloration, scales micro-ornamentation, osteology and hemipenial morphology to A. badius. We also determine the phylogenetic position of A. badius as nested in a composite Guiana Shield clade. In addition, we discuss recent advances on the systematics of Atractus and comment on some ‘new arrangements’ with respect to previously recognized species groups and available morphological evidence. Finally, we highlight the importance of accurate voucher identification before promoting taxonomic changes or implementing nomenclatural acts derived from new phylogenetic hypotheses, and notably propose the synonymy of the recently described A. pyroni with A. roulei.

The genus Stenocercus is composed of 61 species that occur mainly in the Andes and adjacent lowland areas (0-4 000 m) from northern Colombia and Venezuela to central Argentina. In this study, I performed parsimony and Bayesian analyses to infer the phylogenetic relationships among the 20 species of Stenocercus that occur in the northern Andes (Ecuador, Colombia, and Venezuela); I analyzed morphological, molecular, and combined datasets. These analyses resulted in similar topologies, which indicate that species of Stenocercus from the northern Andes are nested within 2 major clades. One of these clades contains 6 species occurring between southern Ecuador and southern Colombia, whereas the other clade includes 13 species that occur from southern Ecuador to northern Colombia and Venezuela. The results also suggest that the recent uplift of the northern Andes has had a major impact on the evolution of Stenocercus.

El género Stenocercus está compuesto por 61 especies que se distribuyen principalmente en los Andes y tierras bajas aledañas (0-4 000 m), desde el norte de Colombia y Venezuela hasta el centro de Argentina. En este trabajo se realizaron análisis de parsimonia e inferencia bayesiana para estudiar las relaciones filogenéticas entre las 20 especies de Stenocercus que habitan en los Andes del norte (Ecuador, Colombia y Venezuela), utilizando datos morfológicos y moleculares por separado y en combinación. Los análisis dieron como resultado topologías similares indicando que las especies de Stenocercus de los Andes del norte están divididas en 2 clados. Uno contiene 6 especies distribuidas entre el sur de Ecuador y sur de Colombia, mientras que el otro tiene 13 especies distribuidas desde el sur de Ecuador hasta el norte de Colombia y Venezuela. Los resultados también sugieren que la reciente formación de los Andes del norte ha tenido gran influencia sobre la evolución de Stenocercus.

We describe a new species of Enyalioides from lowland cloud forests in southwestern Ecuador. This represents the third species in the genus known to occur west of the Andes in South America; the other two species are E. heterolepis and E. oshaughnessyi. Among other characters, the new species can be distinguished from other members in the genus by having small, keeled, paravertebrals; a series of skin folds on the lateral aspects of body and neck; size-homogeneous scales on body and limbs; distinct caudal segments; and an extensive dark patch on the gular region of adult males. Morphological similarity suggests that the new species, which we call E. touzeti, is closely related to E. oshaughnessyi.

Describimos una especie nueva de Enyalioides del bosque nublado al suroccidente de Ecuador. Esta representa la tercera especie de este género que habita al occidente de los Andes en América del Sur; las otras dos especies occidentales son E. heterolepis y E. oshaughnessyi. La especie nueva se diferencia de otras especies del género por tener, entre otras características, paravertebrales pequeñas y quilladas, pliegues dermales a los lados del cuello y cuerpo, escamas homogéneas en el cuerpo y extremidades, segmentos caudales visibles, y un parche oscuro que cubre gran parte de la región gular en machos. Semejanzas morfológicas sugieren que la especie nueva, a la cual llamamos E. touzeti, está cercanamente relacionada con E. oshaughnessyi.