Résumé
Turbinal bones in mammals, due to their roles in thermoregulation and olfaction, are effective indicators for studying ecological habits. Hypothetically, larger respiratory turbinals aid in heat and moisture retention, particularly in challenging environments like those at high elevations. The Andes, with its diverse landscapes and high biodiversity, provides an ideal environment for such studies. Among Andean endemics, the genus Thomasomys-mostly restricted to montane forests and p & aacute;ramos-exhibits high species diversity and adaptability across elevational gradients, making it an ideal candidate for exploring the relationship between ecological niches, habitat selection, and turbinal morphology. Using 3D CT scans of Thomasomys turbinal bones, our study aims to understand the interplay between turbinal surface area and environmental factors (elevation and bioclimatic variables). Our findings reveal consistent turbinal morphological features among Thomasomys species, showing: (i) positive allometric relationships with skull length; (ii) an absence of evolutionary trade-offs between the nasoturbinals and maxilloturbinals and between respiratory and olfactory turbinals; (iii) influence of elevation on the turbinal surface area with lower-elevation species having comparatively smaller turbinal surface areas than higher-elevation species; and (iv) that bioclimatic variables show significant correlations with the proportion of respiratory and olfactory turbinals. Therefore, our results align with the general hypothesis that large respiratory turbinals may help in coping with harsh environmental conditions. However, the relation between elevation and olfactory turbinal surface areas remains puzzling. Various other ecological confounding factors appear to be present and are discussed. Overall, this study sheds light on the complex adaptations of turbinal bones and their interactions with environmental factors, contributing to our understanding of mammalian ecomorphology in montane forest habitats.
This study investigates how the nasal cavity of Thomasomys species adapts to diverse environmental conditions in the Andean montane forests. Using newly generated 3D CT scans of nasal cavities from 45 individuals sampled across a wide elevational range (1,500-3,380 m), we reveal an intricate relationship between elevation, bioclimatic variables, and the turbinals responsible for heat and moisture conservation as well as those involved in olfaction.