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Evolution, diversity, and disparity of the tiger shark lineage Galeocerdo in deep time
Sharks have a long and rich fossil record that consists predominantly of isolated teeth due to the poorly mineralized cartilaginous skeleton. Tiger sharks (Galeocerdo), which represent apex predators in modern oceans, have a known fossil record extending back into the early Eocene (ca. 56 Ma) and co...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
2021
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7612061/ https://www.ncbi.nlm.nih.gov/pubmed/34866693 http://dx.doi.org/10.1017/pab.2021.6 |
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author | Türtscher, Julia López-Romero, Faviel A. Jambura, Patrick L. Kindlimann, René Ward, David J. Kriwet, Jürgen |
author_facet | Türtscher, Julia López-Romero, Faviel A. Jambura, Patrick L. Kindlimann, René Ward, David J. Kriwet, Jürgen |
author_sort | Türtscher, Julia |
collection | PubMed |
description | Sharks have a long and rich fossil record that consists predominantly of isolated teeth due to the poorly mineralized cartilaginous skeleton. Tiger sharks (Galeocerdo), which represent apex predators in modern oceans, have a known fossil record extending back into the early Eocene (ca. 56 Ma) and comprise 22 recognized extinct and one extant species to date. However, many of the fossil species remain dubious, resulting in a still unresolved evolutionary history of the tiger shark genus. Here, we present a revision of the fossil record of Galeocerdo by examining the morphological diversity and disparity of teeth in deep time. We use landmark-based geometric morphometrics to quantify tooth shapes and qualitative morphological characters for species discrimination. Employing this combined approach on fossil and extant tiger shark teeth, our results only support six species to represent valid taxa. Furthermore, the disparity analysis revealed that diversity and disparity are not implicitly correlated and that Galeocerdo retained a relatively high dental disparity since the Miocene despite its decrease from four to one species. With this study, we demonstrate that the combined approach of quantitative geometric morphometric techniques and qualitative morphological comparisons on isolated shark teeth provides a useful tool to distinguish between species with highly similar tooth morphologies. |
format | Online Article Text |
id | pubmed-7612061 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
record_format | MEDLINE/PubMed |
spelling | pubmed-76120612021-12-02 Evolution, diversity, and disparity of the tiger shark lineage Galeocerdo in deep time Türtscher, Julia López-Romero, Faviel A. Jambura, Patrick L. Kindlimann, René Ward, David J. Kriwet, Jürgen Paleobiology Article Sharks have a long and rich fossil record that consists predominantly of isolated teeth due to the poorly mineralized cartilaginous skeleton. Tiger sharks (Galeocerdo), which represent apex predators in modern oceans, have a known fossil record extending back into the early Eocene (ca. 56 Ma) and comprise 22 recognized extinct and one extant species to date. However, many of the fossil species remain dubious, resulting in a still unresolved evolutionary history of the tiger shark genus. Here, we present a revision of the fossil record of Galeocerdo by examining the morphological diversity and disparity of teeth in deep time. We use landmark-based geometric morphometrics to quantify tooth shapes and qualitative morphological characters for species discrimination. Employing this combined approach on fossil and extant tiger shark teeth, our results only support six species to represent valid taxa. Furthermore, the disparity analysis revealed that diversity and disparity are not implicitly correlated and that Galeocerdo retained a relatively high dental disparity since the Miocene despite its decrease from four to one species. With this study, we demonstrate that the combined approach of quantitative geometric morphometric techniques and qualitative morphological comparisons on isolated shark teeth provides a useful tool to distinguish between species with highly similar tooth morphologies. 2021-11 2021-03-24 /pmc/articles/PMC7612061/ /pubmed/34866693 http://dx.doi.org/10.1017/pab.2021.6 Text en https://creativecommons.org/licenses/by/4.0/This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Article Türtscher, Julia López-Romero, Faviel A. Jambura, Patrick L. Kindlimann, René Ward, David J. Kriwet, Jürgen Evolution, diversity, and disparity of the tiger shark lineage Galeocerdo in deep time |
title | Evolution, diversity, and disparity of the tiger shark lineage Galeocerdo in deep time |
title_full | Evolution, diversity, and disparity of the tiger shark lineage Galeocerdo in deep time |
title_fullStr | Evolution, diversity, and disparity of the tiger shark lineage Galeocerdo in deep time |
title_full_unstemmed | Evolution, diversity, and disparity of the tiger shark lineage Galeocerdo in deep time |
title_short | Evolution, diversity, and disparity of the tiger shark lineage Galeocerdo in deep time |
title_sort | evolution, diversity, and disparity of the tiger shark lineage galeocerdo in deep time |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7612061/ https://www.ncbi.nlm.nih.gov/pubmed/34866693 http://dx.doi.org/10.1017/pab.2021.6 |
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