| Predation as the primary selective force in recurrent evolution of gigantism in Poecilozonites land snails in Quaternary Bermuda. | |
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MedLine Citation:
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PMID: 20554560 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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During the last half million years, pulses of gigantism in the anagenetic lineage of land snails of the subgenus Poecilozonites on Bermuda were correlated with glacial periods when lower sea level resulted in an island nearly an order of magnitude larger than at present. During those periods, the island was colonized by large vertebrate predators that created selection pressure for large size and rapid growth in the snails. Extreme reduction in land area from rising seas, along with changes in ecological conditions at the onset of interglacial episodes, marked extinction events for large predators, after which snails reverted to much smaller size. The giant snails were identical in morphology during the last two glacials when the predators included a large flightless rail Rallus recessus (marine isotope stages (MIS) 4-2) and a crane Grus latipes and a duck Anas pachysceles (MIS 6). In a preceding glacial period (MIS 10), when the fauna also included the tortoise Hesperotestudo bermudae, the snails were not only large, but the shells were much thicker, presumably to prevent crushing by tortoises. Evolution of Poecilozonites provides an outstanding example of dramatic morphological change in response to environmental pressures in the absence of cladogenesis. |
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Authors:
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Storrs L Olson; Paul J Hearty |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2010-06-16 |
Journal Detail:
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Title: Biology letters Volume: 6 ISSN: 1744-957X ISO Abbreviation: Biol. Lett. Publication Date: 2010 Dec |
Date Detail:
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Created Date: 2010-11-12 Completed Date: 2011-03-14 Revised Date: 2011-12-23 |
Medline Journal Info:
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Nlm Unique ID: 101247722 Medline TA: Biol Lett Country: England |
Other Details:
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Languages: eng Pagination: 807-10 Citation Subset: IM |
Affiliation:
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National Museum of Natural History, NHB MRC, Smithsonian Institution, Washington, DC 20013-7012, USA. olsons@si.edu |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Bermuda Biological Evolution Body Size Ecosystem Extinction, Biological Food Chain Fossils Selection, Genetic Snails / anatomy & histology*, genetics Vertebrates |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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