Journal article
The stability of thoracic segmentation in trilobites: a case study in developmental and ecological constraints
Evolution & development, Vol.1(1), pp.24-35
07/1999
DOI: 10.1046/j.1525-142x.1999.99005.x
PMID: 11324017
Abstract
The decline in origination rate of new metazoan body plans following the Cambrian radiation has been suggested to reflect developmental canalization in derived taxa, limiting their ability to evolve forms with radically different morphotypes. Segmentation is a fundamental aspect of arthropod body plan, and here we show that a derived trilobite that secondarily converged on a morphotype characteristic of basal members of the clade also reverted to a pattern of segmental variability common among basal trilobites. Hence a secular trend in loss of variability of the trilobite thorax was not due to the evolution of an inviolable developmental constraint. This result challenges the notion of developmental canalization in phylogenetically derived taxa. Rather, early variability in trilobites may be the result of ecological factors that promoted segment-rich thoracic morphotypes during Cambrian time. © BLACKWELL SCIENCE, INC.
Details
- Title: Subtitle
- The stability of thoracic segmentation in trilobites: a case study in developmental and ecological constraints
- Creators
- Nigel C Hughes - University of California, RiversideRalph E Chapman - National Museum of Natural HistoryJonathan M Adrain - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Evolution & development, Vol.1(1), pp.24-35
- Publisher
- Blackwell Science Inc
- DOI
- 10.1046/j.1525-142x.1999.99005.x
- PMID
- 11324017
- ISSN
- 1520-541X
- eISSN
- 1525-142X
- Number of pages
- 12
- Language
- English
- Date published
- 07/1999
- Academic Unit
- Earth and Environmental Sciences
- Record Identifier
- 9984229301702771
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