P2.57 Thursday, Jan. 5 Eye Development in Box Jellyfish VALLEY, J. R.; MARTIN, V.J.*; Appalachian State University; Appalachian State University email@example.com
The complex eyes of the cubozoan jellyfish Carybdea marsupialis exhibit many similarities to the camera-type eyes of higher metazoans including the presence of a cornea, lens and retina of ciliated photoreceptors. During the transformation of the polyp to the eye-bearing medusa, the development and arrangement of several components were followed including the neuropeptide FMRFamide, UV opsin-like protein (indicates photoreceptor formation), J1-crystallin (indicates lens formation) and shielding pigment formation. In following the 14-day transformative process, 8 morphological stages were identified. Starting with a steady-state polyp, the main features of transformation include recession of polyp tentacles, change of symmetry from radial to tetraradial, eye development, emergence of medusa tentacles, and detachment. The first ocelli to appear are the complex eyes followed by the simple ocelli; the small complex eye is the first to exhibit pigment formation (melanin) as well as photoreceptor formation. J1-crystallin was located in the developing lenses/lens-like material in the complex eyes and slit ocelli and also exhibited extracellular extraocular staining. Crystallin staining was present in all six ocelli in adult rhopalia. Extensive neurological rearrangement and development takes place during the transformation. Developmental mechanisms in eye formation similar to both vertebrates and invertebrates were seen including the formation of an ocular placode, formation of an invaginated optic cup, synthesis of a crystallin lens in the optic cup, differentiation of the retina (resulting in multiple photoreceptor populations exhibiting opsin and melanin synthesis) and formation of neuropeptide-producing rhopalial nerves in close vicinity with the eyes/ocelli.