Paulo Passos

Revision of the Epicrates cenchria Complex (Serpentes: Boidae)

Abstract The Epicrates cenchria complex is endemic to the Neotropical region, occurring in mainland portions of Central and South America. The taxonomic status of the nine currently recognized subspecies (E. c. alvarezi, E. c. assisi, E. c. barbouri, E. c. cenchria, E. c. crassus, E. c. gaigei, E. c. hygrophilus, E. c. maurus, and E. c. polylepis), were evaluated based on external morphology, osteology, and hemipenis characters. Results obtained through quantitative and qualitative analyses support the recognition of E. alvarezi, E. assisi, E. cenchria, E. crassus, and E. maurus as distinct species based on statistically robust delimitation of species boundaries.

A NEW SPECIES OF ATRACTUS (SERPENTES: COLUBRIDAE) FROM SOUTHERN BRAZIL

A new species of Atractus is described from grasslands of the State of Rio Grande do Sul, southern Brazil. The new species is distinguished from all congeners by the combination of a single postocular, long loreal, six supralabials, generally six infralabials, 17 dorsal scales rows, six or seven maxillary teeth, and a dorsal color pattern in preservative uniformly grayish-brown with a creamish-white temporal region. Comparisons of the new species are made with all other Atractus species, and its affinities with A. reticulatus and allied species are suggested based on the morphology of the hemipenis.

New Species of Atractus Wagler, 1828 (Serpentes: Dipsadinae) from Guyana Plateau in Northern Brazil

Abstract A new species of Atractus is described from Serra do Surucucu, a mountain slope at 1,000 m in the Guyana Shield, State of Roraima, Brazil. This species, only known by females, is diagnosed from all congeners by the following combination of characters: 17/17/17 smooth dorsal scale rows, without apical pits; 200–207 ventral scales; 25–26 subcaudal scales; moderate sized loreal, contacting second and third supralabials; seven supralabials, third and fourth contacting orbit; seven infralabials, first three contacting chinshields; moderate size, 222–388 mm SVL; short tail (7.7–8.8% snout–vent length); dorsal color pattern, in preservative, uniform chocolate to dark brown, with two conspicuous light paraventral lines, and a light incomplete occipital collar; venter immaculate creamish-white; tail uniform black; five maxillary teeth. We compared the new species with all currently recognized cis-Andean Atractus, and its affinities with Atractus alphonsehogei, Atractus caxiuana, Atractus collaris, Atractus gaigeae, Atractus limitaneus, and Atractus zidoki are discussed on the basis of putative morphological synapomorphies.

A New Species of Atractus (Serpentes: Dipsadinae) from a Relictual Forest in Northeastern Brazil

Abstract A new species of Atractus is described from Serra de Baturité, an Atlantic Forest enclave in the semiarid Caatinga of the state of Ceará, northeastern Brazil. The new species is distinguished from all congeners by the combination of 17 dorsal scale rows at midbody, long loreal, two postoculars, seven upper and lower labials, first four infralabials in contact with chinshields, seven maxillary teeth, moderate body and tail sizes, slightly bilobed and semicapitate hemipenis with lateral-tip projections, light dorsal color pattern uniformly scattered with small dark brown dots, and ventral color pattern uniformly creamish white. The new species shares most of the external morphology and hemipenis characters with A. pantostictus, differing from this taxon by general color pattern and number of subcaudal scales.

New Cryptic Species of Atractus (Serpentes: Dipsadidae) from Brazilian Amazonia

Abstract A new species of Atractus, previously reported as a disjunct population of A. zidoki south of the Amazon River, differs from all congeners in having an undivided sulcus spermaticus. Herein, we restrict the concept of A. zidoki to populations north of the Amazon River, provide a detailed description of its everted hemipenis, and describe a new species to accommodate the population occurring to the south of the Amazon River. Additionally, we briefly discuss intraspecific variation and the systematic value of the hemipenis structure in snakes, mainly with respect to the genus Atractus.

Rediscovery of the Rare Atractus bocki, with Assessment of the Taxonomic Status of Atractus canedii (Serpentes: Colubridae: Dipsadinae)

Abstract Atractus bocki was described based on a single specimen from the Cochabamba region in Bolivia, and since its original description, there have been no further records for the species. During the examination of Argentinean and Bolivian collections, we found four additional specimens of this poorly known snake. In this paper, we describe these individuals and report new data on meristic and morphometric variation for A. bocki. We also evaluate the taxonomic status of Atractus canedii and propose its synonymy with A. bocki.

Three New Atractus (Serpentes: Dipsadidae) from the Andes of Colombia

Abstract Three new species of Atractus are described from the northern Cordillera Central of Colombia. The new species, previously confused with older names, are easily distinguished from any currently recognized Atractus by unique combinations of morphological characters. Additionally, we provide comments on the Atractus diversity and distribution pattern in the Colombian Andes.

Description of two new species from Venezuela in the highly diverse dipsadine genus Atractus (Serpentes: Colubridae)

Two new species of Atractus are described from Venezuela uplands and highlands on two northern Andean cordilleras. Atractus acheronius, known only from Sierra de Perija, can be distinguished from congeners by having 17 dorsal scale rows, presence of preocular scales, seven upper and lower labials, seven maxillary teeth, 166 ventrals in the single female, 23 subcaudals, dorsum brown with small dark brown dots, large body size, huge body diameter, and small tail size. Atractus multidentatus, known only from north versant of the Cordillera de Merida, can be distinguished from congeners by having 17 dorsal scale rows, eight upper and lower labials, 18 maxillary teeth, 153 ventrals in the single female, nine subcaudals, dorsum reddish brown with five longitudinal dark brown stripes, small body size, small body diameter, and small tail size. Additionally, a discussion concerning the species description of Atractus based on unique specimens is provided.

TESTING SPECIES BOUNDARIES WITHIN THE ATRACTUS OCCIPITOALBUS COMPLEX (SERPENTES: DIPSADIDAE)

Abstract The taxonomic status of Atractus occipitoalbus is revised on the basis of concordance between quantitative and qualitative analyses of morphological characters (meristic, morphometric, color pattern, and hemipenis). Atractus duboisi and A. orcesi are herein resurrected based on the number of ventral and subcaudal scales, number of postocular scales, head shape in lateral view, relative tail length, distinct color patterns, and hemipenial morphology. Additionally, a new species, closely related to A. occipitoalbus, is described from the Andean piedmont of Colombia. The new species, represented by a single female, is diagnosed from the A. occipitoalbus female populations on the basis of number of subcaudals, number postocular scales, and dorsal and ventral color patterns.

Rediscovery of Atractus microrhynchus and Reappraisal of the Taxonomic Status of A. emersoni and A. natans (Serpentes: Dipsadidae)

Abstract The species Rhabdosoma microrhynchum (now Atractus microrhynchus) was originally described based on a single specimen collected by the Orton Expedition at “Guayaquil,” in the Guayas province on the Pacific coast of Ecuador. The holotype is currently lost and all specimens previously referred to this species were misidentified on the basis of material from Peruvian Amazonia. While examining museum collections and conducting fieldwork in the Pacific lowlands of Ecuador and Peru, we found specimens assignable to A. microrhynchus. In this study, we report the morphological variation in these new specimens of A. microrhynchus and evaluate the taxonomic status of the Amazonian species previously confused with it. We restrict the concept of A. microrhynchus to the Pacific lowland populations from Ecuador and Peru, and we designate a neotype for the species. Based on the examination of the types of A. emersoni and A. natans from Amazonia, we found that there is wide overlap in the internal and external characters of both taxa. Therefore, A. emersoni is relegated to the synonymy of A. natans. Furthermore, we compared A. microrhynchus with all congeners and discuss its affinities with the A. multicinctus species group based on shared, exclusive hemipenial features. Resumen La especie Rhabdosoma microrhynchum (ahora Atractus microrhynchus) se basó en un solo espécimen colectado por la Expedición Orton en “Guayaquil,” provincia de Guayas, costa Pacífica del Ecuador. El holotipo está actualmente perdido y todos los especímenes previamente referidos a esta especie fueron identificados erróneamente sobre la base de material de la Amazonía Peruana. Durante la revisión de colecciones de museos y la realización de trabajo de campo en las tierras bajas del Pacífico de Ecuador y Perú, encontramos especímenes que se pueden asignar a A. microrhynchus. En este estudio, reportamos sobre la variación morfológica de estos nuevos especímenes de A. microrhynchus y evaluamos el estado taxonómico de las especies Amazónicas previamente confundidas con esta. Restringimos el concepto de A. microrhynchus para las poblaciones de las tierras bajas del Pacífico de Ecuador y Perú y designamos un neotipo para la especie. Basados en la revisión de los tipos de A. emersoni y A. natans de la Amazonía, encontramos que hay una amplia superposición de las características de ambos taxones. Por lo tanto, A. emersoni se coloca bajo la sinonímia de A. natans. Más aún, comparamos A. microrhynchus con todos sus congeners y sus afinidades con el grupo-de-especies A. multicinctus son discutidos sobre la base de las características hemipenianas exclusivas compartidas.