Héctor J. Villavicencio

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.

Thermal ecology of a population of the lizard, Liolaemus pseudoanomalus in western Argentina

The thermal ecology of the lizard Liolaemus pseudoanomalus was studied at La Laja, Albardon Department, San Juan Province, Argentina. Data were collected every 10 days from August 2000 to August 2001 by randomly revisiting bushes and low flagstones across the study site. Each individual was captured by hand, and the cloacal (Tb), substrate (Ts) and air (Ts) temperatures were measured (to nearest 0.1°C) with a rapid reading Miller-Weber thermometer. Tb was not influenced by season, sex or age group. There was a significant positive linear association between Tb/Ta and Tb/Ts. Tb and SVL were not correlated. The average field temperature of the study species was similar to other Liolaemus in the same geographic province. It is concluded that the thermal strategy of the species was heliothermy and thigmothermy.

A New Andean Liolaemus of the L. montanus Series (Squamata: Iguania: Liolaemidae) from Western Argentina

ABSTRACT. A new species of the Iguanian genus Liolaemus, member of the montanus series, is described. The species inhabits altitudes above 4000 meters and is endemic to the Provincial Reserves of Laguna Brava, province of La Rioja, and San Guillermo, province of San Juan, areas located in the Andes mountains of Argentina. Liolaemus sp. nov. has a medium-sized body (maximum SVL = 76.9 mm) with tail subequal in length to the SVL; unkeeled, juxtaposed dorsal scales, in high number around midbody (86–106); precloacal pores in males (4–7), mostly absent in females or in very low number (up to 2 pores); head and body strongly melanic; evident sexual dichromatism, and a distinctive color pattern. Liolaemus sp. nov. lives geographically close but in allopatry to L. andinus, L. eleodori and L. vallecurensis, all species of the montanus series, morphologically alike and probably phylogenetically related to the new species.

Primer registro de infestación en un reptil por larvas de Amblyomma parvitarsum (Acari: Ixodidae) en Argentina

Amblyomma parvitarsum es una garrapata endemica del Altiplano Andino de Argentina, Bolivia, Chile y Peru. En la provincia de San Juan adultos de esta garrapata fueron encontrados en el Parque Nacional San Guillermo sobre Vicugna vicugna . En Argentina tambien existen citas de adultos de A. parvitarsum sobre bovinos, ovinos y el nandu . El primer caso de parasitismo de larvas de A. parvitarsum en Liolaemus fue realizado en Chile. El presente trabajo menciona por primera vez para Argentina la presencia de larvas de A. parvitarsum parasitando al lagarto Liolaemus eleodori.