Abstract Lizards of the Ophiodes genus, popularly known as glass snakes, are exclusively Neotropical. Despite their wide geographic distribution, glass snakes are poorly studied and there are many knowledge gaps in their biology and ecology to be filled. In this context, the objective of this study was to analyze possible sexual and population morphological differences of Ophiodes striatus specimens collected from different municipalities in the state of Minas Gerais, Brazil. A total of 63 specimens belonging to the Herpetological Collection of the Federal University of Juiz de Fora - Reptiles (CHUFJF-Reptiles), collected between 1995 and 2015 were analyzed. All the specimens were necropsied and morphometric measures related to body and head were measured. The males and females analyzed showed similar morphometric measures, and there was no size-related sexual dimorphism. Principal component analysis did not group the analyzed specimens by sex or locality. A positive correlation was observed between the snout-vent length and the vestigial limb length. The present study brings new information related to sexual dimorphism and population morphometric variation of O. striatus, adding information that will help in better understanding the ecology, biology and evolution of the genus in Brazil.

Este estudo investigou o efeito da exposição aguda do zinco (Zn) na histologia do fígado e testículos de lambari do rabo-amarelo (Astyanax aff. Bimaculatus). A exposição consistiu de seis concentrações de Zn, 0, 3, 5, 10, 15 e 20 mg/L por 96 horas de exposição. Fragmentos de fígado e testículos foram processados rotineiramente para inclusão em resina plástica a base de glicol metacrilato. Fragmentos de ossos, músculos, fígado e testículos foram desidratados e digeridos para quantificar os níveis teciduais da absorção de Zn. A exposição aguda a concentrações de acima de 10mg/L produziu alterações estruturais no fígado e gônada. As alterações encontradas no fígado foram: congestão vascular, diminuição do volume celular; deslocamento do núcleo dos hepatócitos, necrose; desarranjo na estrutura do cordonal; infiltrado leucocitário e vacuolização. As alterações encontradas nas gônadas foram ruptura de cisto, retardo no desenvolvimento das células da linhagem germinativa, núcleo picnótico, aglomerado de celular, deslocamento da parede do cisto e vacuolização. As alterações histológicas observadas foram compatíveis com o aumento da concentração de Zn no ambiente, comprometendo as funções hepáticas e reprodutivas, devido ao aumento no número de hepatócitos e redução na produção de espermatozoides.

This study investigated the effect of acute exposition to zinc (Zn) on histology of the liver and testes of yellow tail lambari (Astyanax aff. bimaculatus). The exposure consisted of six concentrations of Zn (0, 3, 5, 10, 15, and 20 mg/L) for 96 hours of exposure. Fragments of liver and testis were routinely processed and embedded in plastic resin based on glycol methacrylate. Fragments of bones, muscles, liver and testis were dehydrated and digested to quantify the absorption levels of Zn in the tissue. Acute exposure to concentrations above 10mg/L has produced structural changes in the liver and gonads. The changes found in the liver were vascular congestion; decrease of cellular volume; displacement of the hepatocyte nucleus; necrosis; disarrangement of cordon structure; leukocyte infiltrate and vacuolization. The changes found in the gonads were ruptured cyst, delayed development of germ cells, pyknotic nucleus, cell cluster, displacement of cyst wall and vacuolization. The histological changes observed were compatible with the increasing concentration of zinc in environment, compromising liver and reproductive functions, because there was an increase in relative frequency of hepatocytes and reduced sperm production