Hindlimb functional morphology and locomotor biomechanics of the small Late Triassic pseudosuchian reptile Gracilisuchus stipanicicorum (Archosauria: Gracilisuchidae)

Autores
Lecuona, Agustina; Keeble, Emily; Lin, Yuting; Hutchinson, John R.
Año de publicación
2025
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Gracilisuchus stipanicorum was a pseudosuchian archosaur from the Late Triassic period in Argentina. Because it was small-bodied with relatively long, slender limbs, traits that are potentially ancestral for archosaurs, such as its locomotor functions, are important to estimate. It has been illustrated as a quadruped with plantigrade autopodia, and probably with an ‘erect’ or ‘semi-erect’ stance, because it is a suchian archosaur, but there has been no deep analysis of these reconstructions. Here, we detail our reconstruction of a three-dimensional digital skeleton of Gracilisuchus from scans of the bones of four main specimens, including the holotype. In this procedure, we found hitherto unrecognised elements of the manus (metacarpals) and incorporated them in our model of the whole organism. We added estimated hindlimb musculature and body segment mass properties to form a musculoskeletal model. This model allowed us to address three key questions: Was it quadrupedal or bipedal; plantigrade or digitigrade; and more sprawling or more erect? Furthermore, we examine how its hindlimb muscle moment arms compare to those of three other small-bodied Triassic archosauriforms and an extant juvenile Nile crocodile in order to assess the diversity and potential evolutionary polarity of these traits. Our analyses of the model support the inferences that Gracilisuchus was quadrupedal (but facultative bipedalism cannot be ruled out) and plantigrade, and not strongly sprawling, but probably not strongly erect hindlimbs; although terming this posture ‘semi-erect’ would be an oversimplification. Gracilisuchus, as modelled here, seems to roughly be a reasonable approximation of the ancestral state of the archosaurian locomotor system. Our synthesis of numerous lines of evidence, from qualitative functional morphology to whole-body centre of mass and muscle moment arms, forms a new reconstruction of Gracilisuchus that future analyses can build on, both biomechanically and comparatively, in order to better understand archosauriform locomotor evolution.
Fil: Lecuona, Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; Argentina
Fil: Keeble, Emily. Royal Veterinary College; Reino Unido
Fil: Lin, Yuting. Royal Veterinary College; Reino Unido
Fil: Hutchinson, John R.. Royal Veterinary College; Reino Unido
Materia
Bipedalism
Functional morphology
Locomotion
Musculoskeletal model
Pseudosuchia
Triassic
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/283194
Acceder
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oai_identifier_str oai:ri.conicet.gov.ar:11336/283194
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network_name_str CONICET Digital (CONICET)
spelling Hindlimb functional morphology and locomotor biomechanics of the small Late Triassic pseudosuchian reptile Gracilisuchus stipanicicorum (Archosauria: Gracilisuchidae)Lecuona, AgustinaKeeble, EmilyLin, YutingHutchinson, John R.BipedalismFunctional morphologyLocomotionMusculoskeletal modelPseudosuchiaTriassichttps://purl.org/becyt/ford/1.5https://purl.org/becyt/ford/1https://purl.org/becyt/ford/1.6https://purl.org/becyt/ford/1Gracilisuchus stipanicorum was a pseudosuchian archosaur from the Late Triassic period in Argentina. Because it was small-bodied with relatively long, slender limbs, traits that are potentially ancestral for archosaurs, such as its locomotor functions, are important to estimate. It has been illustrated as a quadruped with plantigrade autopodia, and probably with an ‘erect’ or ‘semi-erect’ stance, because it is a suchian archosaur, but there has been no deep analysis of these reconstructions. Here, we detail our reconstruction of a three-dimensional digital skeleton of Gracilisuchus from scans of the bones of four main specimens, including the holotype. In this procedure, we found hitherto unrecognised elements of the manus (metacarpals) and incorporated them in our model of the whole organism. We added estimated hindlimb musculature and body segment mass properties to form a musculoskeletal model. This model allowed us to address three key questions: Was it quadrupedal or bipedal; plantigrade or digitigrade; and more sprawling or more erect? Furthermore, we examine how its hindlimb muscle moment arms compare to those of three other small-bodied Triassic archosauriforms and an extant juvenile Nile crocodile in order to assess the diversity and potential evolutionary polarity of these traits. Our analyses of the model support the inferences that Gracilisuchus was quadrupedal (but facultative bipedalism cannot be ruled out) and plantigrade, and not strongly sprawling, but probably not strongly erect hindlimbs; although terming this posture ‘semi-erect’ would be an oversimplification. Gracilisuchus, as modelled here, seems to roughly be a reasonable approximation of the ancestral state of the archosaurian locomotor system. Our synthesis of numerous lines of evidence, from qualitative functional morphology to whole-body centre of mass and muscle moment arms, forms a new reconstruction of Gracilisuchus that future analyses can build on, both biomechanically and comparatively, in order to better understand archosauriform locomotor evolution.Fil: Lecuona, Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Keeble, Emily. Royal Veterinary College; Reino UnidoFil: Lin, Yuting. Royal Veterinary College; Reino UnidoFil: Hutchinson, John R.. Royal Veterinary College; Reino UnidoWiley Blackwell Publishing, Inc2025-11info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/283194Lecuona, Agustina; Keeble, Emily; Lin, Yuting; Hutchinson, John R.; Hindlimb functional morphology and locomotor biomechanics of the small Late Triassic pseudosuchian reptile Gracilisuchus stipanicicorum (Archosauria: Gracilisuchidae); Wiley Blackwell Publishing, Inc; Journal of Anatomy; 11-2025; 1-380021-8782CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/url/https://onlinelibrary.wiley.com/doi/10.1111/joa.70067info:eu-repo/semantics/altIdentifier/doi/10.1111/joa.70067info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2026-08-25T14:40:48Zoai:ri.conicet.gov.ar:11336/283194instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982026-08-25 14:40:48.747CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Hindlimb functional morphology and locomotor biomechanics of the small Late Triassic pseudosuchian reptile Gracilisuchus stipanicicorum (Archosauria: Gracilisuchidae)
title Hindlimb functional morphology and locomotor biomechanics of the small Late Triassic pseudosuchian reptile Gracilisuchus stipanicicorum (Archosauria: Gracilisuchidae)
spellingShingle Hindlimb functional morphology and locomotor biomechanics of the small Late Triassic pseudosuchian reptile Gracilisuchus stipanicicorum (Archosauria: Gracilisuchidae)
Lecuona, Agustina
Bipedalism
Functional morphology
Locomotion
Musculoskeletal model
Pseudosuchia
Triassic
title_short Hindlimb functional morphology and locomotor biomechanics of the small Late Triassic pseudosuchian reptile Gracilisuchus stipanicicorum (Archosauria: Gracilisuchidae)
title_full Hindlimb functional morphology and locomotor biomechanics of the small Late Triassic pseudosuchian reptile Gracilisuchus stipanicicorum (Archosauria: Gracilisuchidae)
title_fullStr Hindlimb functional morphology and locomotor biomechanics of the small Late Triassic pseudosuchian reptile Gracilisuchus stipanicicorum (Archosauria: Gracilisuchidae)
title_full_unstemmed Hindlimb functional morphology and locomotor biomechanics of the small Late Triassic pseudosuchian reptile Gracilisuchus stipanicicorum (Archosauria: Gracilisuchidae)
title_sort Hindlimb functional morphology and locomotor biomechanics of the small Late Triassic pseudosuchian reptile Gracilisuchus stipanicicorum (Archosauria: Gracilisuchidae)
dc.creator.none.fl_str_mv Lecuona, Agustina
Keeble, Emily
Lin, Yuting
Hutchinson, John R.
author Lecuona, Agustina
author_facet Lecuona, Agustina
Keeble, Emily
Lin, Yuting
Hutchinson, John R.
author_role author
author2 Keeble, Emily
Lin, Yuting
Hutchinson, John R.
author2_role author
author
author
dc.subject.none.fl_str_mv Bipedalism
Functional morphology
Locomotion
Musculoskeletal model
Pseudosuchia
Triassic
topic Bipedalism
Functional morphology
Locomotion
Musculoskeletal model
Pseudosuchia
Triassic
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.5
https://purl.org/becyt/ford/1
https://purl.org/becyt/ford/1.6
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv Gracilisuchus stipanicorum was a pseudosuchian archosaur from the Late Triassic period in Argentina. Because it was small-bodied with relatively long, slender limbs, traits that are potentially ancestral for archosaurs, such as its locomotor functions, are important to estimate. It has been illustrated as a quadruped with plantigrade autopodia, and probably with an ‘erect’ or ‘semi-erect’ stance, because it is a suchian archosaur, but there has been no deep analysis of these reconstructions. Here, we detail our reconstruction of a three-dimensional digital skeleton of Gracilisuchus from scans of the bones of four main specimens, including the holotype. In this procedure, we found hitherto unrecognised elements of the manus (metacarpals) and incorporated them in our model of the whole organism. We added estimated hindlimb musculature and body segment mass properties to form a musculoskeletal model. This model allowed us to address three key questions: Was it quadrupedal or bipedal; plantigrade or digitigrade; and more sprawling or more erect? Furthermore, we examine how its hindlimb muscle moment arms compare to those of three other small-bodied Triassic archosauriforms and an extant juvenile Nile crocodile in order to assess the diversity and potential evolutionary polarity of these traits. Our analyses of the model support the inferences that Gracilisuchus was quadrupedal (but facultative bipedalism cannot be ruled out) and plantigrade, and not strongly sprawling, but probably not strongly erect hindlimbs; although terming this posture ‘semi-erect’ would be an oversimplification. Gracilisuchus, as modelled here, seems to roughly be a reasonable approximation of the ancestral state of the archosaurian locomotor system. Our synthesis of numerous lines of evidence, from qualitative functional morphology to whole-body centre of mass and muscle moment arms, forms a new reconstruction of Gracilisuchus that future analyses can build on, both biomechanically and comparatively, in order to better understand archosauriform locomotor evolution.
Fil: Lecuona, Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; Argentina
Fil: Keeble, Emily. Royal Veterinary College; Reino Unido
Fil: Lin, Yuting. Royal Veterinary College; Reino Unido
Fil: Hutchinson, John R.. Royal Veterinary College; Reino Unido
description Gracilisuchus stipanicorum was a pseudosuchian archosaur from the Late Triassic period in Argentina. Because it was small-bodied with relatively long, slender limbs, traits that are potentially ancestral for archosaurs, such as its locomotor functions, are important to estimate. It has been illustrated as a quadruped with plantigrade autopodia, and probably with an ‘erect’ or ‘semi-erect’ stance, because it is a suchian archosaur, but there has been no deep analysis of these reconstructions. Here, we detail our reconstruction of a three-dimensional digital skeleton of Gracilisuchus from scans of the bones of four main specimens, including the holotype. In this procedure, we found hitherto unrecognised elements of the manus (metacarpals) and incorporated them in our model of the whole organism. We added estimated hindlimb musculature and body segment mass properties to form a musculoskeletal model. This model allowed us to address three key questions: Was it quadrupedal or bipedal; plantigrade or digitigrade; and more sprawling or more erect? Furthermore, we examine how its hindlimb muscle moment arms compare to those of three other small-bodied Triassic archosauriforms and an extant juvenile Nile crocodile in order to assess the diversity and potential evolutionary polarity of these traits. Our analyses of the model support the inferences that Gracilisuchus was quadrupedal (but facultative bipedalism cannot be ruled out) and plantigrade, and not strongly sprawling, but probably not strongly erect hindlimbs; although terming this posture ‘semi-erect’ would be an oversimplification. Gracilisuchus, as modelled here, seems to roughly be a reasonable approximation of the ancestral state of the archosaurian locomotor system. Our synthesis of numerous lines of evidence, from qualitative functional morphology to whole-body centre of mass and muscle moment arms, forms a new reconstruction of Gracilisuchus that future analyses can build on, both biomechanically and comparatively, in order to better understand archosauriform locomotor evolution.
publishDate 2025
dc.date.none.fl_str_mv 2025-11
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/11336/283194
Lecuona, Agustina; Keeble, Emily; Lin, Yuting; Hutchinson, John R.; Hindlimb functional morphology and locomotor biomechanics of the small Late Triassic pseudosuchian reptile Gracilisuchus stipanicicorum (Archosauria: Gracilisuchidae); Wiley Blackwell Publishing, Inc; Journal of Anatomy; 11-2025; 1-38
0021-8782
CONICET Digital
CONICET
url http://hdl.handle.net/11336/283194
identifier_str_mv Lecuona, Agustina; Keeble, Emily; Lin, Yuting; Hutchinson, John R.; Hindlimb functional morphology and locomotor biomechanics of the small Late Triassic pseudosuchian reptile Gracilisuchus stipanicicorum (Archosauria: Gracilisuchidae); Wiley Blackwell Publishing, Inc; Journal of Anatomy; 11-2025; 1-38
0021-8782
CONICET Digital
CONICET
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/url/https://onlinelibrary.wiley.com/doi/10.1111/joa.70067
info:eu-repo/semantics/altIdentifier/doi/10.1111/joa.70067
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by/2.5/ar/
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv Wiley Blackwell Publishing, Inc
publisher.none.fl_str_mv Wiley Blackwell Publishing, Inc
dc.source.none.fl_str_mv reponame:CONICET Digital (CONICET)
instname:Consejo Nacional de Investigaciones Científicas y Técnicas
reponame_str CONICET Digital (CONICET)
collection CONICET Digital (CONICET)
instname_str Consejo Nacional de Investigaciones Científicas y Técnicas
repository.name.fl_str_mv CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas
repository.mail.fl_str_mv dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar
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