Rios-Rodas, L.; Rodríguez-Romero, F. de J.; Velázquez-Rodríguez, A. S. & Hernández-Franyutti, A. A.

It has been reported that the air environment is less problematic for organisms in relation to hypoxia except for special circumstances, such as exposure to high altitudes or burrows. The high altitude environment is challenging in different ways, since there are biotic and abiotic factors may interact to determine the distribution and survival of organisms. For these aspects, biology is based on the ecomorphology, area that helps to define the morphological differences with respect to habitat change and geometric morphometrics to analyze statistically those changes. In the present study, we evaluated different populations of the frog Hyla plicata is a species that are distributed at higher elevations in Mexico (1500 m to 3700 m). For the purpose of this study was to analyze the morphology in Hyla plicata heart through an altitudinal gradient. The organisms were collected at four sites, one was located in La Cima (Distrito Federal to 3016 m), and three in the Estado of Mexico: Buenavista (3200 m), El Cerrillo (2632 m) and San Juan Atezcapan (1860 m). The organisms collected were dissected to extract the heart for the purpose of scan them through photographs, and analyzed with geometric points and thus evaluate the shape of the organ. The results indicate that higher altitude locations have enlarged atria and ventricles, indicating that this structure evolved and adapted to effect a more efficient pumping of blood and then direct it to different body tissues. This adaptation in the morphology of the heart, allowed to adapt to Hyla plicata in high altitude environments as seen in other vertebrates that inhabit higher elevations.

RIOS-RODAS, L.; RODRÍGUEZ-ROMERO, F. J.; VELÁZQUEZ- RODRÍGUEZ, A. S. & HERNÁNDEZ-FRANYUTTI, A. A. Geometric Morphometric of the heart in Hyla plicata through an altitudinal gradient in the Mexican Neovolcanic Axe. Int. J. Morphol., 31(3):905-910, 2013.