Cardiovascular system of the Majidae (Crustacea: Decapoda)

The cardiovascular system of majid crabs was mapped using corrosion casting techniques. The general form of the circulatory system was comparable to that of other malacostracan crustaceans, but with distinct differences between several arterial systems. The anterior aorta exited from the anterior surface of the heart supplying hemolymph to the antennae, eyestalks, gastric muscles and brain. This artery was more complex compared with other decapods. The anterolateral arteries exited from the anterior dorsal surface of the heart and supplied hemolymph to the hypodermis, stomach, antennal gland and mandibular muscles. The hepatic arteries were larger and more complex compared with other decapod families, branching profusely within the hepatopancreas and gonads. The small posterior aorta exited from the posterior-ventral surface of the heart. Standard sex-specific differences in this artery were observed. Exiting from the ventral surface of the heart, the sternal artery supplied each pereiopod in a segmental arrangement. The sternal artery arrangement was different to other brachyuran crabs, possibly a symplesiomorphy with segmented ancestors. In accordance with anatomical descriptions of blue crabs and Cancer crabs it would also seem appropriate to classify the circulatory system of the Majidae as one that is “incompletely closed”.