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The trilobite upper limb branch is a well-developed gill

Whether the upper limb branch of Paleozoic “biramous” arthropods, including trilobites, served a respiratory function has been much debated. Here, new imaging of the trilobite Triarthrus eatoni shows that dumbbell-shaped filaments in the upper limb branch are morphologically comparable with gill str...

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Detalles Bibliográficos
Autores principales: Hou, Jin-bo, Hughes, Nigel C., Hopkins, Melanie J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Association for the Advancement of Science 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8011964/
https://www.ncbi.nlm.nih.gov/pubmed/33789898
http://dx.doi.org/10.1126/sciadv.abe7377
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author Hou, Jin-bo
Hughes, Nigel C.
Hopkins, Melanie J.
author_facet Hou, Jin-bo
Hughes, Nigel C.
Hopkins, Melanie J.
author_sort Hou, Jin-bo
collection PubMed
description Whether the upper limb branch of Paleozoic “biramous” arthropods, including trilobites, served a respiratory function has been much debated. Here, new imaging of the trilobite Triarthrus eatoni shows that dumbbell-shaped filaments in the upper limb branch are morphologically comparable with gill structures in crustaceans that aerate the hemolymph. In Olenoides serratus, the upper limb’s partial articulation to the body via an extended arthrodial membrane is morphologically comparable to the junction of the respiratory book gill of Limulus and differentiates it from the typically robust exopod junction in Chelicerata or Crustacea. Apparently limited mechanical rotation of the upper branch may have protected the respiratory structures. Partial attachment of the upper branch to the body wall may represent an intermediate state in the evolution of limb branch fusion between dorsal attachment to the body wall, as in Radiodonta, and ventral fusion to the limb base, as in extant Euarthropoda.
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spelling pubmed-80119642021-04-13 The trilobite upper limb branch is a well-developed gill Hou, Jin-bo Hughes, Nigel C. Hopkins, Melanie J. Sci Adv Research Articles Whether the upper limb branch of Paleozoic “biramous” arthropods, including trilobites, served a respiratory function has been much debated. Here, new imaging of the trilobite Triarthrus eatoni shows that dumbbell-shaped filaments in the upper limb branch are morphologically comparable with gill structures in crustaceans that aerate the hemolymph. In Olenoides serratus, the upper limb’s partial articulation to the body via an extended arthrodial membrane is morphologically comparable to the junction of the respiratory book gill of Limulus and differentiates it from the typically robust exopod junction in Chelicerata or Crustacea. Apparently limited mechanical rotation of the upper branch may have protected the respiratory structures. Partial attachment of the upper branch to the body wall may represent an intermediate state in the evolution of limb branch fusion between dorsal attachment to the body wall, as in Radiodonta, and ventral fusion to the limb base, as in extant Euarthropoda. American Association for the Advancement of Science 2021-03-31 /pmc/articles/PMC8011964/ /pubmed/33789898 http://dx.doi.org/10.1126/sciadv.abe7377 Text en Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC). https://creativecommons.org/licenses/by-nc/4.0/ https://creativecommons.org/licenses/by-nc/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license (https://creativecommons.org/licenses/by-nc/4.0/) , which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited.
spellingShingle Research Articles
Hou, Jin-bo
Hughes, Nigel C.
Hopkins, Melanie J.
The trilobite upper limb branch is a well-developed gill
title The trilobite upper limb branch is a well-developed gill
title_full The trilobite upper limb branch is a well-developed gill
title_fullStr The trilobite upper limb branch is a well-developed gill
title_full_unstemmed The trilobite upper limb branch is a well-developed gill
title_short The trilobite upper limb branch is a well-developed gill
title_sort trilobite upper limb branch is a well-developed gill
topic Research Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8011964/
https://www.ncbi.nlm.nih.gov/pubmed/33789898
http://dx.doi.org/10.1126/sciadv.abe7377
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