Constructional and functional anatomy of Ediacaran rangeomorphs
Abstract Ediacaran rangeomorphs were the first substantially macroscopic organisms to appear in the fossil record, but their underlying biology remains problematic. Although demonstrably heterotrophic, their current interpretation as osmotrophic consumers of dissolved organic carbon (DOC) is incompa...
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crcambridgeupr:10.1017/s0016756820000734 2024-06-23T07:57:25+00:00 Constructional and functional anatomy of Ediacaran rangeomorphs Butterfield, Nicholas J 2020 http://dx.doi.org/10.1017/s0016756820000734 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756820000734 en eng Cambridge University Press (CUP) http://creativecommons.org/licenses/by/4.0/ Geological Magazine volume 159, issue 7, page 1148-1159 ISSN 0016-7568 1469-5081 journal-article 2020 crcambridgeupr https://doi.org/10.1017/s0016756820000734 2024-06-12T04:01:55Z Abstract Ediacaran rangeomorphs were the first substantially macroscopic organisms to appear in the fossil record, but their underlying biology remains problematic. Although demonstrably heterotrophic, their current interpretation as osmotrophic consumers of dissolved organic carbon (DOC) is incompatible with the inertial (high Re ) and advective (high Pe ) fluid dynamics accompanying macroscopic length scales. The key to resolving rangeomorph feeding and physiology lies in their underlying construction. Taphonomic analysis of three-dimensionally preserved Charnia from the White Sea identifies the presence of large, originally water-filled compartments that served both as a hydrostatic exoskeleton and semi-isolated digestion chambers capable of processing recalcitrant substrates, most likely in conjunction with a resident microbiome. At the same time, the hydrodynamically exposed outer surface of macroscopic rangeomorphs would have dramatically enhanced both gas exchange and food delivery. A bag-like epithelium filled with transiently circulated seawater offers an exceptionally efficient means of constructing a simple, DOC-consuming, multicellular heterotroph. Such a body plan is broadly comparable to that of anthozoan cnidarians, minus such derived features as muscle, tentacles and a centralized mouth. Along with other early bag-like fossils, rangeomorphs can be reliably identified as total-group eumetazoans, potentially colonial stem-group cnidarians. Article in Journal/Newspaper White Sea Cambridge University Press White Sea Geological Magazine 1 12 |
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Cambridge University Press |
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crcambridgeupr |
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English |
description |
Abstract Ediacaran rangeomorphs were the first substantially macroscopic organisms to appear in the fossil record, but their underlying biology remains problematic. Although demonstrably heterotrophic, their current interpretation as osmotrophic consumers of dissolved organic carbon (DOC) is incompatible with the inertial (high Re ) and advective (high Pe ) fluid dynamics accompanying macroscopic length scales. The key to resolving rangeomorph feeding and physiology lies in their underlying construction. Taphonomic analysis of three-dimensionally preserved Charnia from the White Sea identifies the presence of large, originally water-filled compartments that served both as a hydrostatic exoskeleton and semi-isolated digestion chambers capable of processing recalcitrant substrates, most likely in conjunction with a resident microbiome. At the same time, the hydrodynamically exposed outer surface of macroscopic rangeomorphs would have dramatically enhanced both gas exchange and food delivery. A bag-like epithelium filled with transiently circulated seawater offers an exceptionally efficient means of constructing a simple, DOC-consuming, multicellular heterotroph. Such a body plan is broadly comparable to that of anthozoan cnidarians, minus such derived features as muscle, tentacles and a centralized mouth. Along with other early bag-like fossils, rangeomorphs can be reliably identified as total-group eumetazoans, potentially colonial stem-group cnidarians. |
format |
Article in Journal/Newspaper |
author |
Butterfield, Nicholas J |
spellingShingle |
Butterfield, Nicholas J Constructional and functional anatomy of Ediacaran rangeomorphs |
author_facet |
Butterfield, Nicholas J |
author_sort |
Butterfield, Nicholas J |
title |
Constructional and functional anatomy of Ediacaran rangeomorphs |
title_short |
Constructional and functional anatomy of Ediacaran rangeomorphs |
title_full |
Constructional and functional anatomy of Ediacaran rangeomorphs |
title_fullStr |
Constructional and functional anatomy of Ediacaran rangeomorphs |
title_full_unstemmed |
Constructional and functional anatomy of Ediacaran rangeomorphs |
title_sort |
constructional and functional anatomy of ediacaran rangeomorphs |
publisher |
Cambridge University Press (CUP) |
publishDate |
2020 |
url |
http://dx.doi.org/10.1017/s0016756820000734 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756820000734 |
geographic |
White Sea |
geographic_facet |
White Sea |
genre |
White Sea |
genre_facet |
White Sea |
op_source |
Geological Magazine volume 159, issue 7, page 1148-1159 ISSN 0016-7568 1469-5081 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1017/s0016756820000734 |
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Geological Magazine |
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12 |
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1802651039013273600 |