Development Genes and Evolution

, Volume 218, Issue 10, pp 511–524

Early development, pattern, and reorganization of the planula nervous system in Aurelia (Cnidaria, Scyphozoa)


  • Nagayasu Nakanishi
    • Department of Ecology and Evolutionary BiologyUCLA
  • David Yuan
    • Department of Ecology and Evolutionary BiologyUCLA
  • David K. Jacobs
    • Department of Ecology and Evolutionary BiologyUCLA
    • Department of Molecular, Cellular and Developmental BiologyUCLA
Original Article

DOI: 10.1007/s00427-008-0239-7

Cite this article as:
Nakanishi, N., Yuan, D., Jacobs, D.K. et al. Dev Genes Evol (2008) 218: 511. doi:10.1007/s00427-008-0239-7


We examined the development of the nervous system in Aurelia (Cnidaria, Scyphozoa) from the early planula to the polyp stage using confocal and transmission electron microscopy. Fluorescently labeled anti-FMRFamide, antitaurine, and antityrosinated tubulin antibodies were used to visualize the nervous system. The first detectable FMRFamide-like immunoreactivity occurs in a narrow circumferential belt toward the anterior/aboral end of the ectoderm in the early planula. As the planula matures, the FMRFamide-immunoreactive cells send horizontal processes (i.e., neurites) basally along the longitudinal axis. Neurites extend both anteriorly/aborally and posteriorly/orally, but the preference is for anterior neurite extension, and neurites converge to form a plexus at the aboral/anterior end at the base of the ectoderm. In the mature planula, a subset of cells in the apical organ at the anterior/aboral pole begins to show FMRFamide-like and taurine-like immunoreactivity, suggesting a sensory function of the apical organ. During metamorphosis, FMRFamide-like immunoreactivity diminishes in the ectoderm but begins to occur in the degenerating primary endoderm, indicating that degenerating FMRFamide-immunoreactive neurons are taken up by the primary endoderm. FMRFamide-like expression reappears in the ectoderm of the oral disc and the tentacle anlagen of the growing polyp, indicating metamorphosis-associated restructuring of the nervous system. These observations are discussed in the context of metazoan nervous system evolution.



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© Springer-Verlag 2008