Hatching larvae of neritimorph gastropods have a bilateral set of both larval and pedal retractor muscles, which is unique among gastropod molluscs. Adults also display a novel connection (“shortcut”) between the two pleural ganglia. To reconstruct the evolution of the novel shortcut between pleural ganglia and its functional role, I studied the development of the central nervous system and muscle innervation in three distinct larval and one post-metamorphic stages of Nerita melanotragus using light and transmission electron microscopy and surface-rendered three-dimensional reconstructions. My results revealed that the novel shortcut is derived from an ancestral nerve connective, which establishes an unconventional link between the ganglia that generate motor output to the bilateral set of larval and pedal retractor muscles to coordinate activity of these muscles. The unique characteristics of the shell, muscles and nervous system in N. melanotragus represent secondarily derived characteristics that co- evolved as an integrated functional unit. / Graduate / 0472
| Identifer | oai:union.ndltd.org:uvic.ca/oai:dspace.library.uvic.ca:1828/6450 |
| Date | 14 August 2015 |
| Creators | Ferguson, Samuel |
| Contributors | Page, Louise Roberta |
| Source Sets | University of Victoria |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Rights | Available to the World Wide Web, http://creativecommons.org/publicdomain/zero/1.0/ |
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