Publications by authors named "Julio M Hoyos"

Plasticity in the critical thermal maximum (CT) helps ectotherms survive in variable thermal conditions. Yet, little is known about the environmental mechanisms modulating its time course. We used the larvae of three neotropical anurans (Boana platanera, Engystomops pustulosus and Rhinella horribilis) to test whether the magnitude of temperature changes and the existence of fluctuations in the thermal environment affected both the amount of change in CT and its acclimation rate (i.

View Article and Find Full Text PDF

Current climate change is generating accelerated increase in extreme heat events and organismal plastic adjustments in upper thermal tolerances, (critical thermal maximum -CT ) are recognized as the quicker mitigating mechanisms. However, current research casts doubt on the actual mitigating role of thermal acclimation to face heat impacts, due to its low magnitude and weak environmental signal. Here, we examined these drawbacks by first estimating maximum extent of thermal acclimation by examining known sources of variation affecting CT expression, such as daily thermal fluctuation and heating rates.

View Article and Find Full Text PDF

The skeleton of the middle ear of lizards is composed of three anatomical elements: columella, extracolumella, and tympanic membrane, with some exceptions that show modifications of this anatomy. The main function of the middle ear is transforming sound waves into vibrations and transmitting these to the inner ear. Most middle ear studies mainly focus on its functional aspects, while few describe the anatomy in detail.

View Article and Find Full Text PDF

Species traits provide a strong link between an organism's fitness and processes at community and ecosystem levels. However, such data remain scarce for amphibians in the Neotropics. Colombia is the country with the highest number of threatened amphibians and the second greatest number of amphibian species worldwide.

View Article and Find Full Text PDF

Although comparative studies of anuran ontogeny have provided new data on heterochrony in the life cycles of frogs, most of them have not included ossification sequences. Using differential staining techniques, we observe and describe differences and similarities of cranial and postcranial development in two hylid species, (Scinaxinae) and (Hylinae), providing new data of ontogenetic studies in these Colombian species. We examined tadpoles raining from Gosner Stages 25 to 45.

View Article and Find Full Text PDF

The first comprehensive description of the skeleton of Atelopus muisca Rueda-Almonacid & Hoyos, 1991 (Bufonidae, Anura) from the Chingaza Natural National Park (Colombia) is provided, and comparisons with some characters described for this species by Coloma and related frogs of the group A. ignescens are done. The humerus of male presenting more developed crista ventralis and crista lateralis, and the articulation of the frontoparietal bones showed the presence of sexual dimorphism.

View Article and Find Full Text PDF