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Bird-Like Anatomy, Posture, and Behavior Revealed by an Early Jurassic Theropod Dinosaur Resting Trace
BACKGROUND: Fossil tracks made by non-avian theropod dinosaurs commonly reflect the habitual bipedal stance retained in living birds. Only rarely-captured behaviors, such as crouching, might create impressions made by the hands. Such tracks provide valuable information concerning the often poorly un...
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Formato: | Texto |
Lenguaje: | English |
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Public Library of Science
2009
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2645690/ https://www.ncbi.nlm.nih.gov/pubmed/19259260 http://dx.doi.org/10.1371/journal.pone.0004591 |
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author | Milner, Andrew R. C. Harris, Jerald D. Lockley, Martin G. Kirkland, James I. Matthews, Neffra A. |
author_facet | Milner, Andrew R. C. Harris, Jerald D. Lockley, Martin G. Kirkland, James I. Matthews, Neffra A. |
author_sort | Milner, Andrew R. C. |
collection | PubMed |
description | BACKGROUND: Fossil tracks made by non-avian theropod dinosaurs commonly reflect the habitual bipedal stance retained in living birds. Only rarely-captured behaviors, such as crouching, might create impressions made by the hands. Such tracks provide valuable information concerning the often poorly understood functional morphology of the early theropod forelimb. METHODOLOGY/PRINCIPAL FINDINGS: Here we describe a well-preserved theropod trackway in a Lower Jurassic (∼198 million-year-old) lacustrine beach sandstone in the Whitmore Point Member of the Moenave Formation in southwestern Utah. The trackway consists of prints of typical morphology, intermittent tail drags and, unusually, traces made by the animal resting on the substrate in a posture very similar to modern birds. The resting trace includes symmetrical pes impressions and well-defined impressions made by both hands, the tail, and the ischial callosity. CONCLUSIONS/SIGNIFICANCE: The manus impressions corroborate that early theropods, like later birds, held their palms facing medially, in contrast to manus prints previously attributed to theropods that have forward-pointing digits. Both the symmetrical resting posture and the medially-facing palms therefore evolved by the Early Jurassic, much earlier in the theropod lineage than previously recognized, and may characterize all theropods. |
format | Text |
id | pubmed-2645690 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2009 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-26456902009-03-04 Bird-Like Anatomy, Posture, and Behavior Revealed by an Early Jurassic Theropod Dinosaur Resting Trace Milner, Andrew R. C. Harris, Jerald D. Lockley, Martin G. Kirkland, James I. Matthews, Neffra A. PLoS One Research Article BACKGROUND: Fossil tracks made by non-avian theropod dinosaurs commonly reflect the habitual bipedal stance retained in living birds. Only rarely-captured behaviors, such as crouching, might create impressions made by the hands. Such tracks provide valuable information concerning the often poorly understood functional morphology of the early theropod forelimb. METHODOLOGY/PRINCIPAL FINDINGS: Here we describe a well-preserved theropod trackway in a Lower Jurassic (∼198 million-year-old) lacustrine beach sandstone in the Whitmore Point Member of the Moenave Formation in southwestern Utah. The trackway consists of prints of typical morphology, intermittent tail drags and, unusually, traces made by the animal resting on the substrate in a posture very similar to modern birds. The resting trace includes symmetrical pes impressions and well-defined impressions made by both hands, the tail, and the ischial callosity. CONCLUSIONS/SIGNIFICANCE: The manus impressions corroborate that early theropods, like later birds, held their palms facing medially, in contrast to manus prints previously attributed to theropods that have forward-pointing digits. Both the symmetrical resting posture and the medially-facing palms therefore evolved by the Early Jurassic, much earlier in the theropod lineage than previously recognized, and may characterize all theropods. Public Library of Science 2009-03-04 /pmc/articles/PMC2645690/ /pubmed/19259260 http://dx.doi.org/10.1371/journal.pone.0004591 Text en This is an open-access article distributed under the terms of the Creative Commons Public Domain declaration which stipulates that, once placed in the public domain, this work may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. https://creativecommons.org/publicdomain/zero/1.0/ This is an open-access article distributed under the terms of the Creative Commons Public Domain declaration, which stipulates that, once placed in the public domain, this work may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. |
spellingShingle | Research Article Milner, Andrew R. C. Harris, Jerald D. Lockley, Martin G. Kirkland, James I. Matthews, Neffra A. Bird-Like Anatomy, Posture, and Behavior Revealed by an Early Jurassic Theropod Dinosaur Resting Trace |
title | Bird-Like Anatomy, Posture, and Behavior Revealed by an Early Jurassic Theropod Dinosaur Resting Trace |
title_full | Bird-Like Anatomy, Posture, and Behavior Revealed by an Early Jurassic Theropod Dinosaur Resting Trace |
title_fullStr | Bird-Like Anatomy, Posture, and Behavior Revealed by an Early Jurassic Theropod Dinosaur Resting Trace |
title_full_unstemmed | Bird-Like Anatomy, Posture, and Behavior Revealed by an Early Jurassic Theropod Dinosaur Resting Trace |
title_short | Bird-Like Anatomy, Posture, and Behavior Revealed by an Early Jurassic Theropod Dinosaur Resting Trace |
title_sort | bird-like anatomy, posture, and behavior revealed by an early jurassic theropod dinosaur resting trace |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2645690/ https://www.ncbi.nlm.nih.gov/pubmed/19259260 http://dx.doi.org/10.1371/journal.pone.0004591 |
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