The evolution of Metriorhynchoidea (mesoeucrocodylia, thalattosuchia): an integrated approach using geometric morphometrics, analysis of disparity, and biomechanics

Young, Mark T. and Brusatte, Stephen L. and Ruta, Marcello and Andrade, Marco Brandalise de (2010) The evolution of Metriorhynchoidea (mesoeucrocodylia, thalattosuchia): an integrated approach using geometric morphometrics, analysis of disparity, and biomechanics. Zoological Journal of the Linnean Society, 158 (4). pp. 801-859. ISSN 0024-4082

Documents
metriorhynchoids.pdf
[img]
[Download]
Request a copy
[img] PDF
metriorhynchoids.pdf - Whole Document
Restricted to Repository staff only

1MB

Official URL: http://dx.doi.org/10.1111/j.1096-3642.2009.00571.x

Abstract

Metriorhynchoid crocodylians represent the pinnacle of marine specialization within Archosauria. Not only were
they a major component of the Middle Jurassic–Early Cretaceous marine ecosystems, but they provide further
examples that extinct crocodilians did not all resemble their modern extant relatives. Here, we use a varied toolkit
of techniques, including phylogenetic reconstruction, geometric morphometrics, diversity counts, discrete character
disparity analysis, and biomechanical finite-element analysis (FEA), to examine the macroevolutionary history of
this clade. All analyses demonstrate that this clade became more divergent, in terms of biodiversity, form, and
function, up until the Jurassic–Cretaceous boundary, after which there is no evidence for recovery or further
radiations. A clear evolutionary trend towards hypercarnivory in Dakosaurus is supported by phylogenetic
character optimization, morphometrics, and FEA, which also support specialized piscivory within Rhacheosaurus
and Cricosaurus. Within Metriorhynchoidea, there is a consistent trend towards increasing marine specialization,
with the hypermarine Cricosaurus exhibiting numerous convergences with other Mesozoic marine reptiles (e.g. loss
of the deltopectoral crest and retracted external nares). In addition, biomechanics, morphometrics, and characterdisparity
analyses consistently distinguish the two newly erected metriorhynchid subfamilies. This study illustrates
that together with phylogeny, quantitative assessment of diversity, form, and function help elucidate the
macroevolutionary pattern of fossil clades.

Item Type:Article
Additional Information:Metriorhynchoid crocodylians represent the pinnacle of marine specialization within Archosauria. Not only were they a major component of the Middle Jurassic–Early Cretaceous marine ecosystems, but they provide further examples that extinct crocodilians did not all resemble their modern extant relatives. Here, we use a varied toolkit of techniques, including phylogenetic reconstruction, geometric morphometrics, diversity counts, discrete character disparity analysis, and biomechanical finite-element analysis (FEA), to examine the macroevolutionary history of this clade. All analyses demonstrate that this clade became more divergent, in terms of biodiversity, form, and function, up until the Jurassic–Cretaceous boundary, after which there is no evidence for recovery or further radiations. A clear evolutionary trend towards hypercarnivory in Dakosaurus is supported by phylogenetic character optimization, morphometrics, and FEA, which also support specialized piscivory within Rhacheosaurus and Cricosaurus. Within Metriorhynchoidea, there is a consistent trend towards increasing marine specialization, with the hypermarine Cricosaurus exhibiting numerous convergences with other Mesozoic marine reptiles (e.g. loss of the deltopectoral crest and retracted external nares). In addition, biomechanics, morphometrics, and characterdisparity analyses consistently distinguish the two newly erected metriorhynchid subfamilies. This study illustrates that together with phylogeny, quantitative assessment of diversity, form, and function help elucidate the macroevolutionary pattern of fossil clades.
Keywords:Crocodylia, diversity, ecomorphology, functional morphology, phylogeny
Subjects:C Biological Sciences > C300 Zoology
C Biological Sciences > C182 Evolution
C Biological Sciences > C191 Biometry
F Physical Sciences > F641 Palaeontology
C Biological Sciences > C181 Biodiversity
Divisions:College of Science > School of Life Sciences
ID Code:6378
Deposited By: Marcello Ruta
Deposited On:01 Oct 2012 00:51
Last Modified:21 Jul 2014 08:20

Repository Staff Only: item control page