Síria Ribeiro

Reptilia, Squamata, Amphisbaenidae, Leposternon spp.: distribution extension, new state record, and geographic distribution map

The genus Leposternon Wagler, 1824 is represented by fossorial squamate reptiles characterized mainly by having head always dorsoventrally compressed, nostril with the opening on the ventral surface of the snout, rostral and nasals fused into a single shield (= rostronasal shield), tail very short with rounded tip, autotomic site tail absent, and presence of pores precloacal in two species (Gans 1971; Porto et al. 2000). Actually, Leposternon is represented by seven species: L. infraorbitale (Berthold, 1859), L. kisteumacheri Porto, Soares & Caramaschi, 2000, L. microcephalum Wagler, 1824, L. octostegum (Duméril, 1851), L. polystegum (Duméril, 1851), L. scutigerum (Hemprich, 1820), and L. wuchereri (Peters, 1879). Species of the genus Leposternon occur in almost all Brazilian states (Figure 1), and with exception of L. microcephalum that occurs also in Bolivia, Paraguay, Argentina, and Uruguay, all other species are endemics from Brazil.

A new two-pored species of Amphisbaena (Squamata, Amphisbaenidae) from the Brazilian Cerrado, with a key to the two-pored species of Amphisbaena.

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); 12-14 dorsal segments and 14-16 ventral in midbody half-annulus; autotomic site between 9-10th caudal annuli; absence of chevron-shaped anterior dorsal half-annuli; 20-23 caudal annuli; postmalar row absent; and precloacals pores arranged in a continuous series of the precloacal half-annuli. Additionally, we present a key for two-pored species of Amphisbaena.

A new species of Leposternon Wagler, 1824 (Squamata, Amphisbaenia) from northeastern Argentina

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 contact each other on the facial portion of the skull. Additionally, we present a key for the species of Leposternon.

Geographic variation and taxonomy of red-tailed Gymnophthalmus (Squamata: Gymnophthalmidae) from Amazonian Savannas

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 savanna enclaves in Amazon, similar to G. vanzoi but with differences in color pattern, have been noted in the literature. Here, we used molecular and morphological data to test the taxonomic status of the Central Amazonian red-tailed Gymnophthalmus (G. sp.). Our molecular analysis recovered a close relationship between G. vanzoi and G. sp. from Central Amazon, with minimal divergence. Samples were similar in scale counts but presented significant variation in color pattern and morphometry. Despite the geographic isolation, individuals of both populations cannot be fully differentiated based on morphology. Thus, our results suggest that G. vanzoi has a wider distribution, including the Central Amazonian red-tailed Gymnophthalmus and likely morphologically similar populations from other enclaves of Amazonian savannas, which may have been isolated recently. Based on our comparative analysis, we highlight some characters proved useful for differentiating Brazilian Gymnophthalmus and discuss some prospects for the taxonomy of the genus.

A new four-pored Amphisbaena Linnaeus, 1758 (Amphisbaenia, Amphisbaenidae) from Brazilian Amazon

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 profile view, sligthly compressed not keeled; pectoral scales arranged in regular annuli; conspicuous autotomic site between 7th-8th caudal annuli; 247-252 dorsal half-annuli; 27 caudal annuli; tail length 9.5-10.4% of snoutvent length; four precloacal pores arranged in sequence; three supralabials; a rounded tail; 22-24 dorsal segments in midbody annulus; postmalar row absent; head length 2.1-2.9% of snout-vent length; prefrontals length 46.6-49.5% of head length; prefrontals suture length 38-44.6% of head length; small malar length 10.6-13.4% of ventral length of head ; second infralabial length 33.8-38.5% of head length; ventral length of head 2.7-2.9% of snout-vent length; mouth length 80.2-81.8% of head length; third infralabial length 16.4-19.6% of head length; snout length 62.5-78.6% of head length; ocular length 23.4-26.2% of head length; mental length 23.2-25.4% of ventral length of head; postmental length 27.2-31.3% of ventral length of head; frontals suture length 23.4-32.3% of head length; postocular width 25-31.9% of maximun width of head; first supralabial length 24.9-30.6% of head length; second supralabial length 27.7-30% of head length and second supralabial height 26.9-28.8% of maximun head height. The hemipenis is bilobed, capitate and with lateral lamellae on the lobes; with a centrally-positioned spermatic groove, bifurcated at the base of the lobes, and with each branch extending to the tip of organ.

A New Species of Leposternon (Squamata: Amphisbaenidae) from Brazilian Cerrado with a Key to Pored Species

Abstract 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 cerradensis, Leposternon kisteumacheri, Leposternon maximus, and Leposternon polystegum. It differs from the pored Leposternon species by a combination of external morphology and dental features. The morphology of the new species is similar to other species of the genus Leposternon with precloacal pores. Resumo Uma nova espécie de Leposternon é descrita do Cerrado brasileiro, com registros em Buritizeiro e João Pinheiro, Minas Gerais, Brasil. A nova espécie pode ser distinguida dos demais congêneres, exceto de Leposternon cerradensis, Leposternon kisteumacheri, Leposternon maximus e Leposternon polystegum, por ter poros pré-cloacais e a maioria das escamas peitorais com formato de diamante. A espécie nova difere das espécies do gênero Leposternon com poros pré-cloacais por uma combinação de atributos da morfologia externa e características dentárias. A morfologia da nova espécie é similar à de outras espécies do gênero Leposternon com poros pré-cloacais.

Distribution extension for Hydrodynastes melanogigas Franco, Fernandes & Bentim, 2007 (Serpentes: Dipsadidae: Xenodontinae) in the Araguaia-Tocantins basin, Brazilian Cerrado

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 Antonio and Ribeirao Cascalheira represent the first records in the state of Mato Grosso, and expand the species’ known distribution some 380 km southwest

Range extension and geographic distribution of Amphisbaena mitchelli Procter, 1923 in the state of Pará, Brazil

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