RESUMO
The structure of the heart and the coronary blood supply of wild mammals, including that of threatened species, are poorly understood. This study set out to describe the heart, aortic arch branching and coronary distribution of Myrmecophaga tridactyla, and to compare it with anatomical descriptions of other Xenarthra given elsewhere. Eight adult giant anteater cadaveric specimens were used in this study. Morphological features of the heart and coronary blood supply were examined using gross dissection as well as latex and cast preparations. The heart lied in the median plane of the thoracic cavity and corresponded to a cone-shape structure with a rounded apex facing left. The internal chambers of the heart comprised the same structures described in other mammals. Two different patterns of coronary blood supply were observed in the giant anteater. Hence, it can be concluded that the three species of Xenarthra share the same heart structure described in other mammals to date. Aortic arch branches and variations in coronary blood supply in this study have been described in carnivores, particularly the cat and the galea. The branching pattern of the coronary artery differed from that of other mammals and may be specific to Myrmecophaga tridactyla. Morphological description of the heart of the giant anteater and comparison with morphological features of other mammals, especially Xenarthra, may assist in phylogenetic analysis and provide significant contributions to clinical anatomy of practical procedures.