<scp>Cardiac morphology of</scp> <i>Chelonoidis carbonaria</i>

Chelonoidis carbonaria is a chelonian that is distinguished mainly by the red or orange coloration of the scales on its head and limbs. The circulatory system of these animals has required morphological adaptations to allow the transition between terrestrial and aquatic environments. The study aimed to perform a cardiac morphological analysis of C. carbonaria. Twelve red-footed tortoise hearts were collected. After this procedure, the material was fixed in a 10% aqueous solution of formaldehyde, and the samples were photo-documented and submitted to standard histological procedures. Using both light and scanning microscopy, the two atria and the ventricle were observed, along with their respective cavities. The hearts of the specimens of C. carbonaria analyzed consisted of three cavities, two atria and one ventricle. The ventricle is subdivided into three sub-chambers: cavum pulmonale, cavum arteriosum, and cavum venosum. The base of the heart has three large vessels: the left aorta, the right aorta, and the pulmonary trunk; the base of the aortas has the intra-aortic septum formed by cartilage. In light and scanning microscopy, the two atria and the ventricle were observed, along with their respective cavities. Additionally, 3D modeling made it possible to produce a study model that highlights the main structures found in the heart of the red-footed tortoise. Considering the aspects studied it was possible to relate the similarity between the anatomical characteristics of the heart of the different species of the order Testudines, with distinctions, mainly in the arrangement of the vessels, when compared with other reptile species.