Graciela Mirta Blanco

Thermal biology of Phymaturus lizards: evolutionary constraints or lack of environmental variation?

Several aspects of the biology of Phymaturus lizards including their herbivorous diet, specialized microhabitat use, and viviparous reproductive mode are highly conserved within the group. Here, we explore two aspects of Phymaturus thermal biology and test for the co-evolution among aspects of the thermal biology in these lizards, such as thermal preferenda and critical temperatures. Secondly, we explore correlations among variation in thermal biology with elevation and latitude. To do so, we used phylogenetically based comparative analyses (PCM) together with conventional statistics. Our results show that thermal biology for Phymaturus is conservative and our data do not suggest the co-evolution of thermal variables. Moreover, we detected low levels of variation in the thermal parameters studied, and no clear relationships between climatic and thermal variables. As a significant association between climatic and thermal variables could be demonstrated for a set of syntopic Liolaemus lizards, we suggest that thermal biology in Phymaturus lizards may be evolutionarily or ecologically constrained.

Reproductive biology and sexual dimorphism of a high-altitude population of the viviparous lizard Phymaturus punae from the Andes in Argentina

Phymaturus punae is a viviparous lizard endemic to the Provincial Reserve San Guillermo, San Juan (Argentina). We present the first life history data of P. punae , belonging to an interesting genus adapted to cold climates. Females reach sexual maturity at 80.6 mm, and males at 84.4 mm snout-vent length. There is sexual dimorphism represented by larger and more robust males, but females show a wider body and a proportionally greater interlimb length than males. In males, spermatozoa become abundant in both testes and epididymi in mid-summer. Vitellogenic and pregnant females occurred simultaneously in late spring and mid-summer indicating a biennial reproductive cycle.

Phimophis vittatus (Boulenger, 1897) (Serpentes: Dipsadidae): Nuevo registro para la provincia de San Juan, Argentina

Se reporta un nuevo registro de Phimophis vittatus para la provincia de San Juan en el departamento Valle Fertil, con material de referencia, confirmando de esta manera la presencia de la especie en la provincia, citada hasta el momento para el departamento de Caucete, sin material de referencia.

The effects of seasonality and precipitation in the avifauna of the Argentine Southern Chaco Serrano

In subtropical regions like the Chaco Serrano (33° S), rainfall has a marked seasonality, and water flood, caused by heavy rains, may have important consequences for dependent ecosystems. Conversely, the high pressure on available resources during dry periods can also affect the fauna diversity and distribution. Even though birds have shown to be excellent ecological indicators of these shifts in the environment, currently little is known about the avifauna of the Argentine Chaco Serrano phytogeographic district. Our aim was to study the resident bird population status in the Southern Chaco Serrano, its fluctuations in richness and abundance, and its relationship to seasonal variations, in monthly and annual hydroperiods. In order to assess the resident bird status over a two year period (2011 Mar.-2013 Feb.) we carried out 18 sampling surveys during pre-breeding (spring), breeding (summer) and non breeding periods (autumn-winter), in the Northeastern part of the Valle Fertil Natural Park, San Juan province, Argentina. During each site survey, we recorded bird assemblages found in six transects, and obtained bird abundance and species diversity. A mixed general linear model was employed to evaluate relationships between the studied variables. We found a total of 98 species of birds belonging to 33 families (44 resident species, 23 spring visitors, six summer visitors, two winter visitors and 23 with scarce registers). We also registered 68 of these species in both hydroperiods, 28 only during rainy periods and only two during the dry period. Both richness and abundance showed the highest values during the pre-breeding and rainy seasons, while different tendencies were detected during the isolated monthly rainfalls. These changes in bird densities were associated with the arrival of migratory species, mainly spring visitors, and probably in relationship with their reproductive activity, and to seasonal fluctuations in food resources. The Southern Chaco Serrano is a subtropical semiarid place that seems to be an important breeding habitat for many migrant bird species, which in turn promoted seasonal changes in species density and diversity, mainly during rainy years. This work contributed to our understanding on the causes of richness and abundance variations on birds, and will contribute to this important group management and conservation in this area.

Primer registro de Ameivula abalosi Cabrera, 2012 (Squamata: Teiidae) en la provincia de San Juan, Argentina

Se informa el primer registro de Ameivula abalosi (Cabrera, 2012) para la provincia de San Juan, departamento Valle Fertil. Asi, se proporciona nueva informacion a los inventarios de la biodiversidad herpetofaunistica de la Reserva de Usos Multiples Valle Fertil y para la provincia de San Juan.

Primer registro de Epictia albipuncta Burmeister, 1861 (Serpentes: Leptotyphlopidae) en la provincia de San Juan, Argentina

En San Juan, de las 20 especies de serpientes citadas, el 55% habitan en regiones de Monte y Chaco, el 20% son de amplia distribucion y el 25% son de distribucion incierta. Los registros de la ofidiofauna para la provincia hasta el presente han sido fruto de hallazgos accidentales. Actualmente se llevan a cabo relevamientos en el Chaco de San Juan destinados especificamente a aumentar el conocimiento de la diversidad de anfibios y reptiles con el fin de aportar informacion para el plan de manejo del area natural protegida Reserva Natural Valle Fertil, entre otros objetivos. En este contexto se reporta por primera vez para San Juan la presencia de Epictia albipuncta (Serpentes: Leptotyphlopidae).

Efectos de la estacionalidad, el sexo y el grupo etario sobre la dieta de Homonota fasciata (Squamata, Phyllodactylidae) en una región del Monte de Argentina

This study aimed to investigate the diet of the gecko Homonota fasciata (Duméril & Bibron, 1836) in a population from Monte of San Juan Province, Argentina, and to analyze possible temporal, sexual, and ontogenetic variations in feeding behavior. We determined the total volume, number, and occurrence frequency of each prey item and calculated the relative importance indexes. We also assessed trophic diversity and trophic equity. Homonota fasciata had a generalist and diverse diet based on arthropods, including insects and arachnids. Individuals adopted a passive ‘sit and wait’ foraging strategy. There were seasonal-, sex-, and age-related variations in the trophic spectra. The results of this study provide a valuable contribution to our understanding of the biology of this species, with implications for the establishment of management guidelines both for the species and its habitat.