The tympanic region of <i>Otaria byronia</i> (Otariidae, Carnivora) – morphology, ontogeny, age classes and dimorphism

Autores
Loza, Cleopatra Mara; Scarano, Alejo Carlos; Galliari, Fernando Carlos; Soibelzon, Leopoldo Héctor; Negrete, Javier; Carlini, Alfredo Armando
Año de publicación
2018
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Here we describe and explore for the first time the ontogeny and sexual dimorphism of the auditory region of Otaria byronia. We studied the tympanic region of skulls of 237 specimens of different ages and sexes. Geometric morphometric methods were used to analyze the tympanic bulla. In addition, 3D reconstructions of the tympanic bulla were performed using computed tomography analysis scans and a serial wearing technique. We provide a description of the external and internal morphology of the tympanic bulla in both sexes and across different stages (bioclasses). The average shape of the bulla in O. byronia has a subtriangular contour, with variations between sexes and ages. Each stage (bioclasses I, II, and III) is characterized by the respective mean shape of the tympanic bulla and designated as a morphoclass (1, 2, and 3). In all cases, the ectotympanic shows greater surface area than the endotympanic, as in other otariids, in contrast to Phocidae. During ontogeny, the relative size of the ectotympanic increases, growing in all directions and covering the endotympanic. This pattern is seen to the greatest extent in adult males, in which the ectotympanic forms an extremely well-developed apophysis jugulare. No differences in internal morphology of the tympanic cavity were recorded between ages and sexes. The bulla does not increase in thickness in successive age classes; in fact, the walls are extremely thin in the adult stages, despite the extensive development of its processes. This pattern is opposite that observed in Phocidae. In morphoclass 3, adult males older than 7 years undergo hypermorphic change that results in a peramorphic condition when compared to adult females. These changes probably follow the same pattern shown by the rest of the skull and contribute to the marked sexual dimorphism of the species.
Facultad de Ciencias Naturales y Museo
Materia
Ciencias Naturales
ontogeny
Otaria byronia
sexual dimorphism
South American sea lion
tympanic bulla
Nivel de accesibilidad
acceso abierto
Condiciones de uso
http://creativecommons.org/licenses/by-nc-sa/4.0/
Repositorio
SEDICI (UNLP)
Institución
Universidad Nacional de La Plata
OAI Identificador
oai:sedici.unlp.edu.ar:10915/127129

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spelling The tympanic region of <i>Otaria byronia</i> (Otariidae, Carnivora) – morphology, ontogeny, age classes and dimorphismLoza, Cleopatra MaraScarano, Alejo CarlosGalliari, Fernando CarlosSoibelzon, Leopoldo HéctorNegrete, JavierCarlini, Alfredo ArmandoCiencias NaturalesontogenyOtaria byroniasexual dimorphismSouth American sea liontympanic bullaHere we describe and explore for the first time the ontogeny and sexual dimorphism of the auditory region of <i>Otaria byronia</i>. We studied the tympanic region of skulls of 237 specimens of different ages and sexes. Geometric morphometric methods were used to analyze the tympanic bulla. In addition, 3D reconstructions of the tympanic bulla were performed using computed tomography analysis scans and a serial wearing technique. We provide a description of the external and internal morphology of the tympanic bulla in both sexes and across different stages (bioclasses). The average shape of the bulla in <i>O. byronia</i> has a subtriangular contour, with variations between sexes and ages. Each stage (bioclasses I, II, and III) is characterized by the respective mean shape of the tympanic bulla and designated as a morphoclass (1, 2, and 3). In all cases, the ectotympanic shows greater surface area than the endotympanic, as in other otariids, in contrast to Phocidae. During ontogeny, the relative size of the ectotympanic increases, growing in all directions and covering the endotympanic. This pattern is seen to the greatest extent in adult males, in which the ectotympanic forms an extremely well-developed apophysis jugulare. No differences in internal morphology of the tympanic cavity were recorded between ages and sexes. The bulla does not increase in thickness in successive age classes; in fact, the walls are extremely thin in the adult stages, despite the extensive development of its processes. This pattern is opposite that observed in Phocidae. In morphoclass 3, adult males older than 7 years undergo hypermorphic change that results in a peramorphic condition when compared to adult females. These changes probably follow the same pattern shown by the rest of the skull and contribute to the marked sexual dimorphism of the species.Facultad de Ciencias Naturales y Museo2018-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf54-71http://sedici.unlp.edu.ar/handle/10915/127129enginfo:eu-repo/semantics/altIdentifier/issn/1469-7580info:eu-repo/semantics/altIdentifier/issn/0021-8782info:eu-repo/semantics/altIdentifier/pmid/29082536info:eu-repo/semantics/altIdentifier/doi/10.1111/joa.12717info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by-nc-sa/4.0/Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-09-03T11:02:48Zoai:sedici.unlp.edu.ar:10915/127129Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-03 11:02:48.65SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv The tympanic region of <i>Otaria byronia</i> (Otariidae, Carnivora) – morphology, ontogeny, age classes and dimorphism
title The tympanic region of <i>Otaria byronia</i> (Otariidae, Carnivora) – morphology, ontogeny, age classes and dimorphism
spellingShingle The tympanic region of <i>Otaria byronia</i> (Otariidae, Carnivora) – morphology, ontogeny, age classes and dimorphism
Loza, Cleopatra Mara
Ciencias Naturales
ontogeny
Otaria byronia
sexual dimorphism
South American sea lion
tympanic bulla
title_short The tympanic region of <i>Otaria byronia</i> (Otariidae, Carnivora) – morphology, ontogeny, age classes and dimorphism
title_full The tympanic region of <i>Otaria byronia</i> (Otariidae, Carnivora) – morphology, ontogeny, age classes and dimorphism
title_fullStr The tympanic region of <i>Otaria byronia</i> (Otariidae, Carnivora) – morphology, ontogeny, age classes and dimorphism
title_full_unstemmed The tympanic region of <i>Otaria byronia</i> (Otariidae, Carnivora) – morphology, ontogeny, age classes and dimorphism
title_sort The tympanic region of <i>Otaria byronia</i> (Otariidae, Carnivora) – morphology, ontogeny, age classes and dimorphism
dc.creator.none.fl_str_mv Loza, Cleopatra Mara
Scarano, Alejo Carlos
Galliari, Fernando Carlos
Soibelzon, Leopoldo Héctor
Negrete, Javier
Carlini, Alfredo Armando
author Loza, Cleopatra Mara
author_facet Loza, Cleopatra Mara
Scarano, Alejo Carlos
Galliari, Fernando Carlos
Soibelzon, Leopoldo Héctor
Negrete, Javier
Carlini, Alfredo Armando
author_role author
author2 Scarano, Alejo Carlos
Galliari, Fernando Carlos
Soibelzon, Leopoldo Héctor
Negrete, Javier
Carlini, Alfredo Armando
author2_role author
author
author
author
author
dc.subject.none.fl_str_mv Ciencias Naturales
ontogeny
Otaria byronia
sexual dimorphism
South American sea lion
tympanic bulla
topic Ciencias Naturales
ontogeny
Otaria byronia
sexual dimorphism
South American sea lion
tympanic bulla
dc.description.none.fl_txt_mv Here we describe and explore for the first time the ontogeny and sexual dimorphism of the auditory region of <i>Otaria byronia</i>. We studied the tympanic region of skulls of 237 specimens of different ages and sexes. Geometric morphometric methods were used to analyze the tympanic bulla. In addition, 3D reconstructions of the tympanic bulla were performed using computed tomography analysis scans and a serial wearing technique. We provide a description of the external and internal morphology of the tympanic bulla in both sexes and across different stages (bioclasses). The average shape of the bulla in <i>O. byronia</i> has a subtriangular contour, with variations between sexes and ages. Each stage (bioclasses I, II, and III) is characterized by the respective mean shape of the tympanic bulla and designated as a morphoclass (1, 2, and 3). In all cases, the ectotympanic shows greater surface area than the endotympanic, as in other otariids, in contrast to Phocidae. During ontogeny, the relative size of the ectotympanic increases, growing in all directions and covering the endotympanic. This pattern is seen to the greatest extent in adult males, in which the ectotympanic forms an extremely well-developed apophysis jugulare. No differences in internal morphology of the tympanic cavity were recorded between ages and sexes. The bulla does not increase in thickness in successive age classes; in fact, the walls are extremely thin in the adult stages, despite the extensive development of its processes. This pattern is opposite that observed in Phocidae. In morphoclass 3, adult males older than 7 years undergo hypermorphic change that results in a peramorphic condition when compared to adult females. These changes probably follow the same pattern shown by the rest of the skull and contribute to the marked sexual dimorphism of the species.
Facultad de Ciencias Naturales y Museo
description Here we describe and explore for the first time the ontogeny and sexual dimorphism of the auditory region of <i>Otaria byronia</i>. We studied the tympanic region of skulls of 237 specimens of different ages and sexes. Geometric morphometric methods were used to analyze the tympanic bulla. In addition, 3D reconstructions of the tympanic bulla were performed using computed tomography analysis scans and a serial wearing technique. We provide a description of the external and internal morphology of the tympanic bulla in both sexes and across different stages (bioclasses). The average shape of the bulla in <i>O. byronia</i> has a subtriangular contour, with variations between sexes and ages. Each stage (bioclasses I, II, and III) is characterized by the respective mean shape of the tympanic bulla and designated as a morphoclass (1, 2, and 3). In all cases, the ectotympanic shows greater surface area than the endotympanic, as in other otariids, in contrast to Phocidae. During ontogeny, the relative size of the ectotympanic increases, growing in all directions and covering the endotympanic. This pattern is seen to the greatest extent in adult males, in which the ectotympanic forms an extremely well-developed apophysis jugulare. No differences in internal morphology of the tympanic cavity were recorded between ages and sexes. The bulla does not increase in thickness in successive age classes; in fact, the walls are extremely thin in the adult stages, despite the extensive development of its processes. This pattern is opposite that observed in Phocidae. In morphoclass 3, adult males older than 7 years undergo hypermorphic change that results in a peramorphic condition when compared to adult females. These changes probably follow the same pattern shown by the rest of the skull and contribute to the marked sexual dimorphism of the species.
publishDate 2018
dc.date.none.fl_str_mv 2018-01
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
Articulo
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info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://sedici.unlp.edu.ar/handle/10915/127129
url http://sedici.unlp.edu.ar/handle/10915/127129
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/issn/1469-7580
info:eu-repo/semantics/altIdentifier/issn/0021-8782
info:eu-repo/semantics/altIdentifier/pmid/29082536
info:eu-repo/semantics/altIdentifier/doi/10.1111/joa.12717
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
eu_rights_str_mv openAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
dc.format.none.fl_str_mv application/pdf
54-71
dc.source.none.fl_str_mv reponame:SEDICI (UNLP)
instname:Universidad Nacional de La Plata
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reponame_str SEDICI (UNLP)
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institution UNLP
repository.name.fl_str_mv SEDICI (UNLP) - Universidad Nacional de La Plata
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