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...
Published in: | Biology Letters |
---|---|
Main Author: | |
Format: | Text |
Language: | English |
Published: |
The Royal Society
2010
|
Subjects: | |
Online Access: | http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3001373 http://www.ncbi.nlm.nih.gov/pubmed/20554559 https://doi.org/10.1098/rsbl.2010.0377 |
id |
ftpubmed:oai:pubmedcentral.nih.gov:3001373 |
---|---|
record_format |
openpolar |
spelling |
ftpubmed:oai:pubmedcentral.nih.gov:3001373 2023-05-15T16:17:58+02:00 Carbonaceous preservation of Cambrian hexactinellid sponge spicules Harvey, Thomas H. P. 2010-12-23 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3001373 http://www.ncbi.nlm.nih.gov/pubmed/20554559 https://doi.org/10.1098/rsbl.2010.0377 en eng The Royal Society http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3001373 http://www.ncbi.nlm.nih.gov/pubmed/20554559 http://dx.doi.org/10.1098/rsbl.2010.0377 © 2010 The Royal Society Palaeontology Text 2010 ftpubmed https://doi.org/10.1098/rsbl.2010.0377 2013-09-03T08:42:40Z 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. Text Forteau Newfoundland PubMed Central (PMC) 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 |
institution |
Open Polar |
collection |
PubMed Central (PMC) |
op_collection_id |
ftpubmed |
language |
English |
topic |
Palaeontology |
spellingShingle |
Palaeontology Harvey, Thomas H. P. Carbonaceous preservation of Cambrian hexactinellid sponge spicules |
topic_facet |
Palaeontology |
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 |
Text |
author |
Harvey, Thomas H. P. |
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://www.ncbi.nlm.nih.gov/pmc/articles/PMC3001373 http://www.ncbi.nlm.nih.gov/pubmed/20554559 https://doi.org/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_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3001373 http://www.ncbi.nlm.nih.gov/pubmed/20554559 http://dx.doi.org/10.1098/rsbl.2010.0377 |
op_rights |
© 2010 The Royal Society |
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 |
_version_ |
1766003982752284672 |