We examined aspects of the population ecology of the Pacific Tree Frog (Hyla regilla) in a meadow of Corn Lily (Veratrum californicum) in the Sierra Nevada Mts. during July 2000. Using mark-recapture techniques we estimate the abundance of H. regilla to be 25±6.8 individuals which translates into a population density of 223.2±60.7 individuals per hectare. The sex ratio of the population of anim...

The causes of amphibian deformities and their role in widespread amphibian declines remain conjectural. Severe limb abnormalities were induced at high frequencies in Pacific treefrogs (Hyla regilla) exposed to cercariae of a trematode parasite (Ribeiroia sp.). The abnormalities closely matched those observed at field sites, and an increase in parasite density caused an increase in abnormality f...

A maximum likelihood approach is described for the analysis of growth increment data derived from tagging experiments. As well as describing mean growth this approach allows the separate estimation of measurement error and growth variability, and uses mixture theory to provide an objective way of dealing with outliers. The method is illustrated using data for Pacific bonito (Sarda chiliensis) a...

The tepuis of South America are massive flattop mountains with cliffs up to 1000m and summits up to 3100m. Tepuis hold enormous endemicity levels, but little is known about the origins of the endemic flora and fauna. Recently diverged lineages offer the possibility of understanding the origins of summit endemicity by examining population dynamics and dispersal. We examine species delimitation, ...

Five species of anuran amphibians, all belonging to the family Hylidae, were collected at Praia das Neves, municipality of President Kennedy, southeastern Brazil. The species were represented by four genera: Scinax, Hyla, Aparasphenodon, and Trachycephalus. Four species (A. brunoi, Hyla albomarginata, Scinax altera, and S. cuspidatus) were found during the dry season (August 1999), and two (A. ...

Intra- and interspecific cross combinations between the tetraploid treefrog Hyla versicolor, and between H. versicolor and the diploid treefrog Hyla chrysoscelis were performed. Progeny phenotypes resulting from these crosses were examined electrophoretically using a polymorphic glutamate oxaloacetic transaminase (GOT-1) locus, to determine the mechanism of chromosome segregation in H. versicol...