Tracing the evolution of the holothurian body plan through stem-group fossils
2013 | journal article. A publication with affiliation to the University of Göttingen.
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- Authors
- Smith, Andrew B.; Reich, Mike
- Abstract
- The fossil echinoderm Palaeocucumaria, from the early Devonian Hunsruck Slate of southwestern Germany, has been studied using both traditional techniques and X-ray microtomography, and its anatomy clarified. Phylogenetic analysis shows that it is a stem-group holothurian with a combination of characters that help understand how the modern (crown-group) holothurian body plan developed. Echinoids and holothurians have evolved along different paths, by differential growth of the larval- and rudment-derived body regions. Palaeocucumaria shows that late stem-group holothurians had a water vascular organization with a single external madreporite and calcified stone canal leading to the aboral end of the peripharyngeal coelom, and five primary radial water vessels that gave rise to tentacle-like tube-feet. This fossil data, in combination with a molecular phylogeny based on 18s-like rRNA gene sequence data, is used to order evolutionary steps in the making of the crown-group holothurian body plan.(c) 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109, 670-681.
- Issue Date
- 2013
- Status
- published
- Publisher
- Wiley-blackwell
- Journal
- Biological Journal of the Linnean Society
- ISSN
- 0024-4066