The First Metriorhynchid Crocodylomorph from the Middle Jurassic of Spain, with Implications for Evolution of the Subclade Rhacheosaurini

Background: Marine deposits from the Callovian of Europe have yielded numerous species of metriorhynchid crocodylomorphs. While common in English and French Formations, metriorhynchids are poorly known from the Iberian Peninsula. Twenty years ago an incomplete, but beautifully preserved, skull was d...

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Autores: Parrilla-Bel, J., Young, M.T., Moreno-Azanza, M., Canudo, J.I.
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2013
País:España
Institución:Universidad de Zaragoza
Repositorio:Zaguán. Repositorio Digital de la Universidad de Zaragoza
OAI Identifier:oai:zaguan.unizar.es:63322
Acceso en línea:http://zaguan.unizar.es/record/63322
Access Level:acceso abierto
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spelling The First Metriorhynchid Crocodylomorph from the Middle Jurassic of Spain, with Implications for Evolution of the Subclade RhacheosauriniParrilla-Bel, J.Young, M.T.Moreno-Azanza, M.Canudo, J.I.Background: Marine deposits from the Callovian of Europe have yielded numerous species of metriorhynchid crocodylomorphs. While common in English and French Formations, metriorhynchids are poorly known from the Iberian Peninsula. Twenty years ago an incomplete, but beautifully preserved, skull was discovered from the Middle Callovian of Spain. It is currently the oldest and best preserved metriorhynchid specimen from the Iberian Peninsula. Until now it has never been properly described and its taxonomic affinities remained obscure. Methodology/Principal Findings: Here we present a comprehensive description for this specimen and in doing so we refer it to a new genus and species: Maledictosuchus riclaensis. This species is diagnosed by numerous autapomorphies, including: heterodont dentition; tightly interlocking occlusion; lachrymal anterior process excludes the jugal from the preorbital fenestra; orbits longer than supratemporal fenestrae; palatine has two non-midline and one midline anterior processes. Our phylogenetic analysis finds Maledictosuchus riclaensis to be the basal-most known member of Rhacheosaurini (the subclade of increasingly mesopelagic piscivores that includes Cricosaurus and Rhacheosaurus). Conclusions/Significance: Our description of Maledictosuchus riclaensis shows that the craniodental morphologies that underpinned the success of Rhacheosaurini in the Late Jurassic and Early Cretaceous, as a result of increasing marine specialization to adaptations for feeding on fast small-bodied prey (i.e. divided and retracted external nares; reorientation of the lateral processes of the frontal; elongate, tubular rostrum; procumbent and non-carinated dentition; high overall tooth count; and dorsolaterally inclined paroccipital processes), first appeared during the Middle Jurassic. Rhacheosaurins were curiously rare in the Middle Jurassic, as only one specimen of Maledictosuchus riclaensis is known (with no representatives discovered from the well-sampled Oxford Clay Formation of England). As such, the feeding/marine adaptations of Rhacheosaurini did not confer an immediate selective advantage upon the group, and it took until the Late Jurassic for this subclade to dominate in Western Europe.2013info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfhttp://zaguan.unizar.es/record/63322reponame:Zaguán. Repositorio Digital de la Universidad de Zaragozainstname:Universidad de ZaragozaInglésinfo:eu-repo/grantAgreement/ES/DGA/B105-10info:eu-repo/grantAgreement/ES/MINECO/CGL2010-16447info:eu-repo/semantics/openAccessoai:zaguan.unizar.es:633222026-05-29T13:59:51Z
dc.title.none.fl_str_mv The First Metriorhynchid Crocodylomorph from the Middle Jurassic of Spain, with Implications for Evolution of the Subclade Rhacheosaurini
title The First Metriorhynchid Crocodylomorph from the Middle Jurassic of Spain, with Implications for Evolution of the Subclade Rhacheosaurini
spellingShingle The First Metriorhynchid Crocodylomorph from the Middle Jurassic of Spain, with Implications for Evolution of the Subclade Rhacheosaurini
Parrilla-Bel, J.
title_short The First Metriorhynchid Crocodylomorph from the Middle Jurassic of Spain, with Implications for Evolution of the Subclade Rhacheosaurini
title_full The First Metriorhynchid Crocodylomorph from the Middle Jurassic of Spain, with Implications for Evolution of the Subclade Rhacheosaurini
title_fullStr The First Metriorhynchid Crocodylomorph from the Middle Jurassic of Spain, with Implications for Evolution of the Subclade Rhacheosaurini
title_full_unstemmed The First Metriorhynchid Crocodylomorph from the Middle Jurassic of Spain, with Implications for Evolution of the Subclade Rhacheosaurini
title_sort The First Metriorhynchid Crocodylomorph from the Middle Jurassic of Spain, with Implications for Evolution of the Subclade Rhacheosaurini
dc.creator.none.fl_str_mv Parrilla-Bel, J.
Young, M.T.
Moreno-Azanza, M.
Canudo, J.I.
author Parrilla-Bel, J.
author_facet Parrilla-Bel, J.
Young, M.T.
Moreno-Azanza, M.
Canudo, J.I.
author_role author
author2 Young, M.T.
Moreno-Azanza, M.
Canudo, J.I.
author2_role author
author
author
description Background: Marine deposits from the Callovian of Europe have yielded numerous species of metriorhynchid crocodylomorphs. While common in English and French Formations, metriorhynchids are poorly known from the Iberian Peninsula. Twenty years ago an incomplete, but beautifully preserved, skull was discovered from the Middle Callovian of Spain. It is currently the oldest and best preserved metriorhynchid specimen from the Iberian Peninsula. Until now it has never been properly described and its taxonomic affinities remained obscure. Methodology/Principal Findings: Here we present a comprehensive description for this specimen and in doing so we refer it to a new genus and species: Maledictosuchus riclaensis. This species is diagnosed by numerous autapomorphies, including: heterodont dentition; tightly interlocking occlusion; lachrymal anterior process excludes the jugal from the preorbital fenestra; orbits longer than supratemporal fenestrae; palatine has two non-midline and one midline anterior processes. Our phylogenetic analysis finds Maledictosuchus riclaensis to be the basal-most known member of Rhacheosaurini (the subclade of increasingly mesopelagic piscivores that includes Cricosaurus and Rhacheosaurus). Conclusions/Significance: Our description of Maledictosuchus riclaensis shows that the craniodental morphologies that underpinned the success of Rhacheosaurini in the Late Jurassic and Early Cretaceous, as a result of increasing marine specialization to adaptations for feeding on fast small-bodied prey (i.e. divided and retracted external nares; reorientation of the lateral processes of the frontal; elongate, tubular rostrum; procumbent and non-carinated dentition; high overall tooth count; and dorsolaterally inclined paroccipital processes), first appeared during the Middle Jurassic. Rhacheosaurins were curiously rare in the Middle Jurassic, as only one specimen of Maledictosuchus riclaensis is known (with no representatives discovered from the well-sampled Oxford Clay Formation of England). As such, the feeding/marine adaptations of Rhacheosaurini did not confer an immediate selective advantage upon the group, and it took until the Late Jurassic for this subclade to dominate in Western Europe.
publishDate 2013
dc.date.none.fl_str_mv 2013
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dc.identifier.none.fl_str_mv http://zaguan.unizar.es/record/63322
url http://zaguan.unizar.es/record/63322
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv info:eu-repo/grantAgreement/ES/DGA/B105-10
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dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
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