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Transient role of the middle ear as a lower jaw support across mammals

Mammals articulate their jaws using a novel joint between the dentary and squamosal bones. In eutherian mammals, this joint forms in the embryo, supporting feeding and vocalisation from birth. In contrast, marsupials and monotremes exhibit extreme altriciality and are born before the bones of the no...

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Autores principales: Anthwal, Neal, Fenelon, Jane C, Johnston, Stephen D, Renfree, Marilyn B, Tucker, Abigail S
Formato: Online Artículo Texto
Lenguaje:English
Publicado: eLife Sciences Publications, Ltd 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7363448/
https://www.ncbi.nlm.nih.gov/pubmed/32600529
http://dx.doi.org/10.7554/eLife.57860
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author Anthwal, Neal
Fenelon, Jane C
Johnston, Stephen D
Renfree, Marilyn B
Tucker, Abigail S
author_facet Anthwal, Neal
Fenelon, Jane C
Johnston, Stephen D
Renfree, Marilyn B
Tucker, Abigail S
author_sort Anthwal, Neal
collection PubMed
description Mammals articulate their jaws using a novel joint between the dentary and squamosal bones. In eutherian mammals, this joint forms in the embryo, supporting feeding and vocalisation from birth. In contrast, marsupials and monotremes exhibit extreme altriciality and are born before the bones of the novel mammalian jaw joint form. These mammals need to rely on other mechanisms to allow them to feed. Here, we show that this vital function is carried out by the earlier developing, cartilaginous incus of the middle ear, abutting the cranial base to form a cranio-mandibular articulation. The nature of this articulation varies between monotremes and marsupials, with juvenile monotremes retaining a double articulation, similar to that of the fossil mammaliaform Morganucodon, while marsupials use a versican-rich matrix to stabilise the jaw against the cranial base. These findings provide novel insight into the evolution of mammals and the changing relationship between the jaw and ear.
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spelling pubmed-73634482020-07-17 Transient role of the middle ear as a lower jaw support across mammals Anthwal, Neal Fenelon, Jane C Johnston, Stephen D Renfree, Marilyn B Tucker, Abigail S eLife Developmental Biology Mammals articulate their jaws using a novel joint between the dentary and squamosal bones. In eutherian mammals, this joint forms in the embryo, supporting feeding and vocalisation from birth. In contrast, marsupials and monotremes exhibit extreme altriciality and are born before the bones of the novel mammalian jaw joint form. These mammals need to rely on other mechanisms to allow them to feed. Here, we show that this vital function is carried out by the earlier developing, cartilaginous incus of the middle ear, abutting the cranial base to form a cranio-mandibular articulation. The nature of this articulation varies between monotremes and marsupials, with juvenile monotremes retaining a double articulation, similar to that of the fossil mammaliaform Morganucodon, while marsupials use a versican-rich matrix to stabilise the jaw against the cranial base. These findings provide novel insight into the evolution of mammals and the changing relationship between the jaw and ear. eLife Sciences Publications, Ltd 2020-06-30 /pmc/articles/PMC7363448/ /pubmed/32600529 http://dx.doi.org/10.7554/eLife.57860 Text en © 2020, Anthwal et al http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/licenses/by/4.0/This article is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use and redistribution provided that the original author and source are credited.
spellingShingle Developmental Biology
Anthwal, Neal
Fenelon, Jane C
Johnston, Stephen D
Renfree, Marilyn B
Tucker, Abigail S
Transient role of the middle ear as a lower jaw support across mammals
title Transient role of the middle ear as a lower jaw support across mammals
title_full Transient role of the middle ear as a lower jaw support across mammals
title_fullStr Transient role of the middle ear as a lower jaw support across mammals
title_full_unstemmed Transient role of the middle ear as a lower jaw support across mammals
title_short Transient role of the middle ear as a lower jaw support across mammals
title_sort transient role of the middle ear as a lower jaw support across mammals
topic Developmental Biology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7363448/
https://www.ncbi.nlm.nih.gov/pubmed/32600529
http://dx.doi.org/10.7554/eLife.57860
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