Title
Evolution, diversity, and disparity of the tiger shark lineage Galeocerdo in deep time
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Abstract
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.
Keywords
PaleontologyGeneral Agricultural and Biological SciencesEcologyEcology, Evolution, Behavior and Systematics
Object type
Language
English [eng]
Persistent identifier
https://phaidra.univie.ac.at/o:1437414
Appeared in
Title
Paleobiology
Volume
47
Issue
4
ISSN
0094-8373
Issued
2021
From page
574
To page
590
Publisher
Cambridge University Press (CUP)
Date issued
2021
Access rights
Rights statement
© The Author(s), 2021
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