Síria L.B. Ribeiro

• PhD
• Professor at Federal University of Western Pará

The lizard genus Uracentron, family Tropiduridae, is composed of the species Uracentron flaviceps (Guichenot, 1855) and Uracentron azureum (Linnaeus, 1758). Both species have arboreal habits and are endemic to the Amazon. Here we report a new geographical record of Uracentron azureum guentheri from western Pará State, Brazil, and the first record f...

A new species of Amphisbaena is described from the north of Espinhaço Mountain Range, municipality of Caetité, state of Bahia, Brazil. Amphisbaena amethystasp. nov. can be distinguished from its congeners by the following combination of characters: (1) snout convex in profile, slightly compressed not keeled; (2) pectoral scales arranged in regular...

Morphological patterns may vary spatially in response to adaptations to regional environmental conditions. In fossorial animals, edaphic gradients potentially predict intra and interspecific morphological variation because they can limit dispersal and select morphotypes. We measured morphological traits of South American worm lizards, including thr...

We reassessed the type-series of Amphisbaena ibijara and Amphisbaena frontalis to evaluate the characters used to diagnose and distinguish them, and compared these data with additional specimens of A. ibijara. We found broadly overlapping ranges of the quantitative diagnostic characters, and no differences between the qualitative characters, that c...

Sexual selection, fecundity selection and ecological divergence have been the main explanations proposed for the origin and maintenance of sexual dimorphism. In this study we provide evidence of sexual dimorphism in the South American aquatic snake Helicops polylepis, which is mainly determined by body and head sizes. Males have longer tails and mo...

Comparing reproductive tract morphology between closely-related species may reveal mechanisms and processes leading to reproductive isolation and cladogenesis. Differences in external morphology are often inconspicuous between closely-related Neotropical species, and tissue samples for DNA sequencing are usually scarce for fossorial organisms such...

Phimophis guerini Duméril, Bibron & Duméril, 1854 is a Xenodontinae snake distributed in Argentina, Brazil and Paraguay. In Brazil, the species is broadly distributed, occurring mainly in open areas of the Cerrado, but also in the Amazon, Atlantic forest and Caatinga. We provide a new record for this species from the municipality of Santarém in the...

Here, we describe a new species of Amphisbaena with two precloacal pores from open Cerrado areas of the municipality of Arenópolis, in the Brazilian state of Goiás. The new species differs from other South American amphisbaenids by the folllowing combination of characters: (1) snout rounded in dorsal view and slightly convex in lateral view; (2) tw...

Gymnophthalmus represents a challenging group for systematics of microteiid lizards. Due to scarcity of exemplars and molecular data, the taxonomy of the genus has been unstable, and six of its eight species are considered part of a poorly-delimited complex of unisexual and bisexual species. Unnamed populations of red-tailed Gymnophthalmus from sav...

Zootaxa 4420 (4): 451-474 Abstract A new species of Amphisbaena is described from the Brazilian Amazon, within the area impacted by the Teles Pires hydroelectric power plant, Jacareacanga municipality, State of Pará. Amphisbaena hoogmoedi sp. nov. can be diagnosed from its congeners by the following combination of characters: snout convex in profil...

A new species of Leposternon is described from the Brazilian Cerrado, with records from the municipalities of Buritizeiro and João Pinheiro, state of Minas Gerais, central Brasil. The new species has precloacal pores and pectorals scales mostly diamond shaped, and these characteristics distinguish it from all congeners except Leposternon cerradensi...

We present new records for Hydrodynastes melanogigas Franco, Fernandes & Bentim, 2007, from eastern Mato Grosso state, Central Brazil. The four specimens found in the municipalities of Novo Santo Antônio and Ribeirão Cascalheira represent the first records in the state of Mato Grosso, and expand the species’ known distribution some 380 km southwest

A new species of Amphisbaena is described from municipalities of Babaçulândia, State of Tocantins, and Estreito, State of Maranhão, northern Brazilian Cerrado. The new species differs from other two-pored species of the genus, by presenting mainly slender body shape; snout rounded in profile and dorsal view; high number of body annuli (328-342); 12...

Worm lizards remain one of the least known groups of vertebrates, hindering a proper assessment of their levels of threat, especially in tropical regions where worm lizard diversity is highest and habitat destruction is rampant. We examine trends in description dates, conservation status and their correlations with body and range size, and conduct...

A new species of Leposternon is described from the Humid Chaco biome in Argentina. The species is known only from its type locality, at El Bagual Ecological Reserve, a conservation unit located in the province of Formosa. The new species can be distinguished from all its congeners by the presence of rostral processes in the maxillae and nasals that...

We present here a new record for Amphisbaena michelli for the western of Pará State, northern Brazil. The specimen was found in the municipality of Belterra, on the right bank of the Tapajós River, and represents an expansion ca. 350 km west of the previously known geographic distribution of the species.

We revised the taxonomic status of Amphisbaena prunicolor and A. albocingulata, two taxa traditionally recognized as subspecies of A. prunicolor in the A. darwini complex. Despite some authors elevated both taxa to the specific rank, its taxonomic decisions were made without specific commentaries and/or proper diagnostic characters. The comparison...

A new species of Leposternon is described from the Brazilian Cerrado, Goiás and Minas Gerais states. The known range is restricted to the headwaters of the Paranã and São Francisco drainage systems. The new species has the following diagnostic characters: frontal portion of head strongly depressed, pectoral shield modified, autotomic site absent, 4...

Aim To test predictions of the vicariance model, to define basic biogeographical units for Cerrado squamates, and to discuss previous biogeographical hypotheses. Location Cerrado; South American savannas south of the Amazon, extending across central Brazil, with marginal areas in Bolivia and Paraguay and isolated relictual enclaves in adjacent regi...

A new species of keel-headed amphisbaenian of the genus Anops is described from the Cerrado of the Jalapão region, Tocantins state, Brazil. This new species of Anops is described from a single specimen, which may be easily distinguished from the other species of the genus, Anops bilabialatus and Anops kingii, by showing an extremely narrow head (37...

A new species of Leposternon is described from the Brazilian Cerrado, southwestern Goiás state. The new species is diagnosed mainly by the following characters: two–four precloacal pores, 299–341 dorsal postpectoral half-annuli, 302– 349 ventral postpectoral half-annuli, 13–15 tail annuli, 118–121 precloacal vertebrae, two supralabials, two infrala...

Nesse estudo nós apresentamos uma revisão taxonômica e uma proposta filogenética para o gênero de anfisbênios Leposternon com base em caracteres morfológicos. Nós identificamos a alta variação morfológica de algumas espécies (e.g. Leposternon microcephalum e L. infraorbitale) como o principal problema a taxonomia do gênero. Como resultados da revis...