Xenosaurus

Abstract: Observations on the ecology of Xenosaurus grandis near Cuautlapan, Veracruz revealed that this rarely studied lizard is locally abundant in crevices of boulders in perennial tropical forest. Individuals are solitary and highly aggressive when placed together. A diurnally active thermal conformer, body temperatures (average = 22.7?C) correlate with both substrate and air temperatures and basking was not observed. Upper thermal limits (CTM) averaged 37.4?C. Food consisted primarily of insects by volume (Lepidoptera larvae and Orthoptera predominated), but occasional lizard prey are taken. RESUMEN Observaciones ecologicas de Xenosaurus grandis en las cercanias de Cuautlapan, Veracruz, muestran que este lagarto poco estudiado abunda localmente en las grietas de rocas del bosque tropical perenne. Al ser juntados, los individuos son solitarios y muy agresivos. Siendo diurnos y conformistas termales, sus temperaturas corporales (promedio = 22.70C) estan correlacionadas con las temperaturas del substrato y del aire, y no se observo las lagartillas tomando sol. Los limites termales superiores (CTM) promedian 37.4?C. Su alimento consisto principalmente (por volumen) en insectos (predominantemente larvas de Lepidopteros y Ortopteros), aunque ocasionalmente otros largartos son consumidos.

Abstract: Virus isolation attempts were carried out on wild-caught Xenosaurus grandis, X. platyceps, and Abronia graminea from Mexico. These animals were also tested for exposure to paramyxoviruses and reoviruses. Pharyngeal and cloacal swabs were collected from 30 lizards, and blood was collected from 23 lizards. A cytopathogenic virus was isolated from the cloacal swab of one of the X. platyceps. The isolate was identified as a paramyxovirus on the basis of its sensitivity to chloroform, resistance to 5-iodo-2′-deoxyuridine, size and morphology of the viral particles, hemagglutination of chicken erythrocytes, and serologic reaction with paramyxovirus-specific antisera. Antibodies against the paramyxovirus isolated in this study were found in four animals from three species. Antibodies against a different paramyxovirus isolated from a monitor lizard were found in seven animals from three species, showing that all the species tested are susceptible to paramyxovirus infections. Antibodies to a reptilian reo...

Abstract: We document variation among 13 populations of distinct species of the lizard genus Xenosaurus in four key reproductive traits: minimum size at maturity, litter size, size at birth, and relative clutch mass (RCM). Despite a common flattened morphology, considerable variation occurs in the examined traits. Minimum size at maturity varied between 92 and 110 mm snout–vent length (SVL), average litter size ranged between 2.1 and 5.7 newborns per female, mean size at birth varied between 40.6 and 51.6 mm SVL, and average RCM ranged between 0.16 and 0.35. We also found considerable interpopulational variation in mean size of reproductive females (from 102.9–119.2 mm SVL) and in the length of the birth season (from about one month to four months distributed between early May and late September). Litter size and RCM were the most variable traits with coefficients of variation above 20, whereas the other traits showed coefficients of variation between 4 and 7.4. Only the minimum size at maturity showed an ...

Abstract: We studied growth and demography in a population of Xenosaurus newmanorum a lizard that lives in rock crevices in the tropical cloud forests of Mexico. Growth rates varied with season (faster in the wet season) and year (faster in 1995 and 1997, slower in 1996 and 1999). Males and females did not differ in growth rate. Proportion of reproductive females varied from year to year, with 1996 having the lowest proportion of reproductive females (32.5%) compared to the other years (all >75%). The age/size structure changed slightly among years, but did not differ between the wet and dry seasons. On average, the sex ratio was female-biased; however, the proportion of males in the population was greater in the dry season than in the wet season. Our results suggest that, like other lizards, growth and demographic characteristics of this population fluctuate with the proximate environment on both a seasonal and annual timescale.