Anatomical studies of the coronary system in elasmobranchs: I. Coronary arteries in lamnoid sharks.

A study of the anatomy of coronary arteries has been done in five shark species of the order Lamniformes: Isurus oxyrinchus, Isurus paucus, Lamna nasus, Alopias superciliosus, and Alopias vulpinus. The study, which included 26 specimens, was carried out with the injection-corrosion technique, obtaining internal casts of the main trunks and coronary arterial branches. The results have shown a high degree of constancy in the coronary patterns in all species and a number of general features common to all of them, except for Alopias vulpinus. In this species, a mesh-like ventricular pattern of intramyocardial vessels was found instead of subepicardial ventricular coronary branches with a definite pattern. It was also shown that there is a wide range of variation among the species regarding the relative importance of the dorsal and ventral coronary trunks. Thus, Isurus oxyrinchus showed a clear predominance of the ventral coronary trunk, whereas in Alopias superciliosus, most of the ventricle was supplied by branches derived from the dorsal coronary trunk.