Morphology of heart and vessels of the cardiac base in Magellanic penguin (Spheniscus magellanicus)

ABSTRACT Magellanic penguin is medium-sized seabird originated from southern hemisphere with colonies near Patagonia. At certain times of the year in Brazilian coast, a few penguins lose their hunting routes and can´t return because they are very sick. Thirty-four penguins died in Espírito Santo´s coast. This study analyzed the cardiac morphology and morph metric of heart chambers and walls, valves, and arteries of the cardiac base. These parts were analysed and stained by Hematoxilin and eosin and Gomori´s trichrome. Mainly targeting the collagen´s composition in each described part the Picru-sirius Red´s stain under polarized light was used. Among thirty-four penguin hearts, none presented discrepancy in morphology, they were all very similar. The characterization of collagen by Picrusirius Red stain highlighted type 1 collagen in comparison to type 3 collagen in most structures, giving a more reddish appearance in almost of them. In conclusion, the cardiac anatomy of the Magellanic Penguin is similar to that of other birds, with a predominance of type I collagen.