Evolution of the Cardiovascular System in Crustacea

Abstract

An attempt is made to explain the evolution of different cardiovascular morphologies of crustaceans on the basis of (1) changes in the development of the body plan of different species, (2) the advent in the malacostracans of segmental arteries that provided the circulatory potential for growth in body size and speciation, (3) the need for more powerful hearts to propel blood through larger bodies, and (4) the embryological substrate that would allow for the development of regional specialization. Electrophysiological evidence supports the hypothesis that the archetypal crustacean heart was myogenic, but in more advanced forms this pacemaking mechanism has become subservient to the neural drive from the cardiac ganglion. This transition may have been the result of the selective advantages to possessing a discrete cardiac ganglion, which itself was easily controlled by nervous inputs from the CNS and by circulating hormones.