A simple visual system without neurons in jellyfish larvae

Summary, in English

Earlier detailed studies of cnidarian planula larvae have revealed a simple nervous system but no eyes or identifiable light sensing structures. Here, we describe the planula of a box jellyfish, Tripedalia cystophora, and report that these larvae have an extremely simple organization with no nervous system at all. Their only advanced feature is the presence of 10-15 pigment-cup ocelli, evenly spaced across the posterior half of the larval ectoderm. The ocelli are single cell structures containing a cup of screening pigment filled with presumably photosensory microvilli. These rhabdomeric photoreceptors have no neural connections to any other cells, but each has a well-developed motor-cilium, appearing to be the only means by which light can control the behaviour of the larva. The ocelli are thus self-contained sensory-motor entities, making a nervous system superfluous.

• Author: Karin Nordström; Rita Wallén; Jamie Seymour; Dan-E Nilsson
• Department/s: Department of Biology; Functional zoology; Lund Vision Group
• Publishing year: 2003
• Language: English
• Pages: 2349-2354
• Publication/Series: Royal Society of London. Proceedings B. Biological Sciences
• Volume: 270
• Issue: 1531
• Full text: - 4 MB; Download statistics
• Links: http://dx.doi.org/10.1098/rspb.2003.2504
• Document type: Journal article
• Publisher: Royal Society Publishing
• Topic: Zoology
• Status: Published
• Research group: Lund Vision Group
• ISBN/ISSN/Other: ISSN: 1471-2954