Macelognathus vagans (archosauria; crocodylomorpha): new information on the braincase using ct-data

Autores
Leardi, Juan Martín; Pol, Diego; Clark, James Matthew
Año de publicación
2016
Idioma
inglés
Tipo de recurso
documento de conferencia
Estado
versión publicada
Descripción
Macelognathus vagans was originally described as a dinosaur by Marsh from the Late Jurassic Morrison Formation of Wyoming and later Ostrom suggested crocodilian affinities. More recently, Göhlich and collaborators identified new material from Colorado as a basal crocodylomorph. However, a partial skull found in association with mandibular and postcranial remains was not described. The skull preserves most of the posterior part, including the braincase, and probably belongs to a juvenile given its dorsal curvature. Due to the small size and delicate structures within the braincase, micro CT studies were performed on this specimen. This new material reinforces the non-crocodyliform crocodylomorph affinities of Macelognathus as it bears a large otic aperture, unfused frontals and lacks ornamentation on the dorsal cranial bones. The internal struc-tures also support these affinities as this specimen has traits (i.e., heavily pneumatized and expanded basisphenoid; the presence of additional pneumatic features on the braincase; and the otoccipital-quadrate contact) not present in most basal crocodylomorphs. Furthermore, the presence of a wide supraoccipital and a cranioquadrate passage are traits shared with Almadasuchus from the early Late Jurassic of Argentina. The new anatomical information was incorporated in a phylogenetic dataset, expanding both character and taxon sampling. Macelognathus was recovered as one of the most derived noncrocodyliform crocodylomorphs, forming a clade with two other Late Jurassic taxa (Almadasuchus and the Morrison Hallopus). This derived clade is characterized by having a higher degree of suturing of the braincase, posteriorly closed otic aperture (paralleled in mesoeucrocodylians) and cursorial adaptations.
Fil: Leardi, Juan Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina
Fil: Pol, Diego. Museo Paleontológico Egidio Feruglio; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Clark, James Matthew. The George Washington University; Estados Unidos
XXX Jornadas Argentinas de Paleontología de Vertebrados
Buenos Aires
Argentina
Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"
Asociación Paleontológica Argentina
Materia
Crocodylomorpha
Braincase
Evolution
Phylogeny
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/242312

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spelling Macelognathus vagans (archosauria; crocodylomorpha): new information on the braincase using ct-dataLeardi, Juan MartínPol, DiegoClark, James MatthewCrocodylomorphaBraincaseEvolutionPhylogenyhttps://purl.org/becyt/ford/1.5https://purl.org/becyt/ford/1Macelognathus vagans was originally described as a dinosaur by Marsh from the Late Jurassic Morrison Formation of Wyoming and later Ostrom suggested crocodilian affinities. More recently, Göhlich and collaborators identified new material from Colorado as a basal crocodylomorph. However, a partial skull found in association with mandibular and postcranial remains was not described. The skull preserves most of the posterior part, including the braincase, and probably belongs to a juvenile given its dorsal curvature. Due to the small size and delicate structures within the braincase, micro CT studies were performed on this specimen. This new material reinforces the non-crocodyliform crocodylomorph affinities of Macelognathus as it bears a large otic aperture, unfused frontals and lacks ornamentation on the dorsal cranial bones. The internal struc-tures also support these affinities as this specimen has traits (i.e., heavily pneumatized and expanded basisphenoid; the presence of additional pneumatic features on the braincase; and the otoccipital-quadrate contact) not present in most basal crocodylomorphs. Furthermore, the presence of a wide supraoccipital and a cranioquadrate passage are traits shared with Almadasuchus from the early Late Jurassic of Argentina. The new anatomical information was incorporated in a phylogenetic dataset, expanding both character and taxon sampling. Macelognathus was recovered as one of the most derived noncrocodyliform crocodylomorphs, forming a clade with two other Late Jurassic taxa (Almadasuchus and the Morrison Hallopus). This derived clade is characterized by having a higher degree of suturing of the braincase, posteriorly closed otic aperture (paralleled in mesoeucrocodylians) and cursorial adaptations.Fil: Leardi, Juan Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Pol, Diego. Museo Paleontológico Egidio Feruglio; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Clark, James Matthew. The George Washington University; Estados UnidosXXX Jornadas Argentinas de Paleontología de VertebradosBuenos AiresArgentinaMuseo Argentino de Ciencias Naturales "Bernardino Rivadavia"Asociación Paleontológica ArgentinaAsociación Paleontológica Argentina2016info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/conferenceObjectJornadaJournalhttp://purl.org/coar/resource_type/c_5794info:ar-repo/semantics/documentoDeConferenciaapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/242312Macelognathus vagans (archosauria; crocodylomorpha): new information on the braincase using ct-data; XXX Jornadas Argentinas de Paleontología de Vertebrados; Buenos Aires; Argentina; 2016; 24-251851-8044CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/url/https://www.ameghiniana.org.ar/index.php/ameghiniana/article/view/3066/4807Nacionalinfo:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-29T10:34:41Zoai:ri.conicet.gov.ar:11336/242312instacron: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:34982025-09-29 10:34:41.745CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Macelognathus vagans (archosauria; crocodylomorpha): new information on the braincase using ct-data
title Macelognathus vagans (archosauria; crocodylomorpha): new information on the braincase using ct-data
spellingShingle Macelognathus vagans (archosauria; crocodylomorpha): new information on the braincase using ct-data
Leardi, Juan Martín
Crocodylomorpha
Braincase
Evolution
Phylogeny
title_short Macelognathus vagans (archosauria; crocodylomorpha): new information on the braincase using ct-data
title_full Macelognathus vagans (archosauria; crocodylomorpha): new information on the braincase using ct-data
title_fullStr Macelognathus vagans (archosauria; crocodylomorpha): new information on the braincase using ct-data
title_full_unstemmed Macelognathus vagans (archosauria; crocodylomorpha): new information on the braincase using ct-data
title_sort Macelognathus vagans (archosauria; crocodylomorpha): new information on the braincase using ct-data
dc.creator.none.fl_str_mv Leardi, Juan Martín
Pol, Diego
Clark, James Matthew
author Leardi, Juan Martín
author_facet Leardi, Juan Martín
Pol, Diego
Clark, James Matthew
author_role author
author2 Pol, Diego
Clark, James Matthew
author2_role author
author
dc.subject.none.fl_str_mv Crocodylomorpha
Braincase
Evolution
Phylogeny
topic Crocodylomorpha
Braincase
Evolution
Phylogeny
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.5
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv Macelognathus vagans was originally described as a dinosaur by Marsh from the Late Jurassic Morrison Formation of Wyoming and later Ostrom suggested crocodilian affinities. More recently, Göhlich and collaborators identified new material from Colorado as a basal crocodylomorph. However, a partial skull found in association with mandibular and postcranial remains was not described. The skull preserves most of the posterior part, including the braincase, and probably belongs to a juvenile given its dorsal curvature. Due to the small size and delicate structures within the braincase, micro CT studies were performed on this specimen. This new material reinforces the non-crocodyliform crocodylomorph affinities of Macelognathus as it bears a large otic aperture, unfused frontals and lacks ornamentation on the dorsal cranial bones. The internal struc-tures also support these affinities as this specimen has traits (i.e., heavily pneumatized and expanded basisphenoid; the presence of additional pneumatic features on the braincase; and the otoccipital-quadrate contact) not present in most basal crocodylomorphs. Furthermore, the presence of a wide supraoccipital and a cranioquadrate passage are traits shared with Almadasuchus from the early Late Jurassic of Argentina. The new anatomical information was incorporated in a phylogenetic dataset, expanding both character and taxon sampling. Macelognathus was recovered as one of the most derived noncrocodyliform crocodylomorphs, forming a clade with two other Late Jurassic taxa (Almadasuchus and the Morrison Hallopus). This derived clade is characterized by having a higher degree of suturing of the braincase, posteriorly closed otic aperture (paralleled in mesoeucrocodylians) and cursorial adaptations.
Fil: Leardi, Juan Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina
Fil: Pol, Diego. Museo Paleontológico Egidio Feruglio; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Clark, James Matthew. The George Washington University; Estados Unidos
XXX Jornadas Argentinas de Paleontología de Vertebrados
Buenos Aires
Argentina
Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"
Asociación Paleontológica Argentina
description Macelognathus vagans was originally described as a dinosaur by Marsh from the Late Jurassic Morrison Formation of Wyoming and later Ostrom suggested crocodilian affinities. More recently, Göhlich and collaborators identified new material from Colorado as a basal crocodylomorph. However, a partial skull found in association with mandibular and postcranial remains was not described. The skull preserves most of the posterior part, including the braincase, and probably belongs to a juvenile given its dorsal curvature. Due to the small size and delicate structures within the braincase, micro CT studies were performed on this specimen. This new material reinforces the non-crocodyliform crocodylomorph affinities of Macelognathus as it bears a large otic aperture, unfused frontals and lacks ornamentation on the dorsal cranial bones. The internal struc-tures also support these affinities as this specimen has traits (i.e., heavily pneumatized and expanded basisphenoid; the presence of additional pneumatic features on the braincase; and the otoccipital-quadrate contact) not present in most basal crocodylomorphs. Furthermore, the presence of a wide supraoccipital and a cranioquadrate passage are traits shared with Almadasuchus from the early Late Jurassic of Argentina. The new anatomical information was incorporated in a phylogenetic dataset, expanding both character and taxon sampling. Macelognathus was recovered as one of the most derived noncrocodyliform crocodylomorphs, forming a clade with two other Late Jurassic taxa (Almadasuchus and the Morrison Hallopus). This derived clade is characterized by having a higher degree of suturing of the braincase, posteriorly closed otic aperture (paralleled in mesoeucrocodylians) and cursorial adaptations.
publishDate 2016
dc.date.none.fl_str_mv 2016
dc.type.none.fl_str_mv info:eu-repo/semantics/publishedVersion
info:eu-repo/semantics/conferenceObject
Jornada
Journal
http://purl.org/coar/resource_type/c_5794
info:ar-repo/semantics/documentoDeConferencia
status_str publishedVersion
format conferenceObject
dc.identifier.none.fl_str_mv http://hdl.handle.net/11336/242312
Macelognathus vagans (archosauria; crocodylomorpha): new information on the braincase using ct-data; XXX Jornadas Argentinas de Paleontología de Vertebrados; Buenos Aires; Argentina; 2016; 24-25
1851-8044
CONICET Digital
CONICET
url http://hdl.handle.net/11336/242312
identifier_str_mv Macelognathus vagans (archosauria; crocodylomorpha): new information on the braincase using ct-data; XXX Jornadas Argentinas de Paleontología de Vertebrados; Buenos Aires; Argentina; 2016; 24-25
1851-8044
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://www.ameghiniana.org.ar/index.php/ameghiniana/article/view/3066/4807
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https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.coverage.none.fl_str_mv Nacional
dc.publisher.none.fl_str_mv Asociación Paleontológica Argentina
publisher.none.fl_str_mv Asociación Paleontológica Argentina
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