Carbonaceous preservation of Cambrian hexactinellid sponge spicules
Early fossil sponges offer a direct window onto the evolutionary emergence of animals, but insights are limited by the paucity of characters preserved in the conventional fossil record. Here, a new preservational mode for sponge spicules is reported from the lower Cambrian Forteau Formation (Newfoun...
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crroyalsociety:10.1098/rsbl.2010.0377 2024-06-02T08:06:49+00:00 Carbonaceous preservation of Cambrian hexactinellid sponge spicules Harvey, Thomas H. P. 2010 http://dx.doi.org/10.1098/rsbl.2010.0377 https://royalsocietypublishing.org/doi/pdf/10.1098/rsbl.2010.0377 https://royalsocietypublishing.org/doi/full-xml/10.1098/rsbl.2010.0377 en eng The Royal Society https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ Biology Letters volume 6, issue 6, page 834-837 ISSN 1744-9561 1744-957X journal-article 2010 crroyalsociety https://doi.org/10.1098/rsbl.2010.0377 2024-05-07T14:16:28Z Early fossil sponges offer a direct window onto the evolutionary emergence of animals, but insights are limited by the paucity of characters preserved in the conventional fossil record. Here, a new preservational mode for sponge spicules is reported from the lower Cambrian Forteau Formation (Newfoundland, Canada), prompting a re-examination of proposed homologies and sponge inter-relationships. The spicules occur as wholly carbonaceous films, and are interpreted as the remains of robust organic spicule sheaths. Comparable sheaths are restricted among living taxa to calcarean sponges, although the symmetries of the fossil spicules are characteristic of hexactinellid sponges. A similar extinct character combination has been documented in the Burgess Shale fossil Eiffelia . Interpreting the shared characters as homologous implies complex patterns of spicule evolution, but an alternative interpretation as convergent autapomorphies is more parsimonious. In light of the mutually exclusive distributions of these same characters among the crown groups, this result suggests that sponges exhibited an early episode of disparity expansion followed by comparatively constrained evolution, a pattern shared with many other metazoans but obscured by the conventional fossil record of sponges. Article in Journal/Newspaper Forteau Newfoundland The Royal Society Burgess ENVELOPE(76.128,76.128,-69.415,-69.415) Canada Forteau ENVELOPE(-56.965,-56.965,51.467,51.467) Biology Letters 6 6 834 837 |
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Open Polar |
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The Royal Society |
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crroyalsociety |
language |
English |
description |
Early fossil sponges offer a direct window onto the evolutionary emergence of animals, but insights are limited by the paucity of characters preserved in the conventional fossil record. Here, a new preservational mode for sponge spicules is reported from the lower Cambrian Forteau Formation (Newfoundland, Canada), prompting a re-examination of proposed homologies and sponge inter-relationships. The spicules occur as wholly carbonaceous films, and are interpreted as the remains of robust organic spicule sheaths. Comparable sheaths are restricted among living taxa to calcarean sponges, although the symmetries of the fossil spicules are characteristic of hexactinellid sponges. A similar extinct character combination has been documented in the Burgess Shale fossil Eiffelia . Interpreting the shared characters as homologous implies complex patterns of spicule evolution, but an alternative interpretation as convergent autapomorphies is more parsimonious. In light of the mutually exclusive distributions of these same characters among the crown groups, this result suggests that sponges exhibited an early episode of disparity expansion followed by comparatively constrained evolution, a pattern shared with many other metazoans but obscured by the conventional fossil record of sponges. |
format |
Article in Journal/Newspaper |
author |
Harvey, Thomas H. P. |
spellingShingle |
Harvey, Thomas H. P. Carbonaceous preservation of Cambrian hexactinellid sponge spicules |
author_facet |
Harvey, Thomas H. P. |
author_sort |
Harvey, Thomas H. P. |
title |
Carbonaceous preservation of Cambrian hexactinellid sponge spicules |
title_short |
Carbonaceous preservation of Cambrian hexactinellid sponge spicules |
title_full |
Carbonaceous preservation of Cambrian hexactinellid sponge spicules |
title_fullStr |
Carbonaceous preservation of Cambrian hexactinellid sponge spicules |
title_full_unstemmed |
Carbonaceous preservation of Cambrian hexactinellid sponge spicules |
title_sort |
carbonaceous preservation of cambrian hexactinellid sponge spicules |
publisher |
The Royal Society |
publishDate |
2010 |
url |
http://dx.doi.org/10.1098/rsbl.2010.0377 https://royalsocietypublishing.org/doi/pdf/10.1098/rsbl.2010.0377 https://royalsocietypublishing.org/doi/full-xml/10.1098/rsbl.2010.0377 |
long_lat |
ENVELOPE(76.128,76.128,-69.415,-69.415) ENVELOPE(-56.965,-56.965,51.467,51.467) |
geographic |
Burgess Canada Forteau |
geographic_facet |
Burgess Canada Forteau |
genre |
Forteau Newfoundland |
genre_facet |
Forteau Newfoundland |
op_source |
Biology Letters volume 6, issue 6, page 834-837 ISSN 1744-9561 1744-957X |
op_rights |
https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ |
op_doi |
https://doi.org/10.1098/rsbl.2010.0377 |
container_title |
Biology Letters |
container_volume |
6 |
container_issue |
6 |
container_start_page |
834 |
op_container_end_page |
837 |
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1800751791191621632 |