SATTERLIE, R.A.: Comparative Neuroanatomy of Jellyfish Swim Systems: Romanes is Still the Man

In the late 1800’s Romanes distinguished between the “covered-eyed medusae” and the “naked-eyed medusae”. These groups represent the scyphomedusae and hydromedusae respectively. While the mechanics of swimming in both groups of jellyfish show many similarities, the underlying neuronal mechanisms for activating the swimming musculature is very different in the two groups. Furthermore, the recent separation of the cubomedusae from the Class Scyphozoa requires further investigation of swim control in these highly efficient swimmers to allow speculation on their phylogenetic linkages. Immmnohistochemical techniques, utilizing antibodies to alpha and beta tubulin, and the neuroactive peptide FMRFamide, were used to selectively stain nervous tissue in medusae from all three Classes; Hydrozoa, Scyphozoa and Cubozoa. This data is used to back up known physiological properties of the three groups, and to further highlight Romanes’ separation between the “covered-eyed” and “naked-eyed” medusae, including the placement of cubomedusae in the dichotomy.