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The evolutionary history of the tiger shark, Galeocerdo cuvier

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See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/328968537

The evolutionary history of the tiger shark, Galeocerdo cuvier

Conference Paper · November 2018

CITATIONS 0

5 authors, including:

Some of the authors of this publication are also working on these related projects:

Reappraisal of two key Fossil-Lagerstätten in Scaglia deposits of northeastern Italy in the context of Late Cretaceous climatic variability: a multidisciplinary approach View project

Evolutionary history of pycnodontiform fishes (Osteichthyes, Neopterygii) View project Julia Türtscher

University of Vienna

4 PUBLICATIONS   0 CITATIONS    SEE PROFILE

Patrick Leopold Jambura University of Vienna 16 PUBLICATIONS   1 CITATION    SEE PROFILE Giuseppe Marramà University of Vienna 49 PUBLICATIONS   210 CITATIONS    SEE PROFILE René Kindlimann 10 PUBLICATIONS   80 CITATIONS    SEE PROFILE

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The evolutionary history of the tiger shark,

Galeocerdo cuvier

Julia Türtscher1, Patrick L. Jambura1, Giuseppe Marramà1, René Kindlimann2, Jürgen

Kriwet1

1University of Vienna, Department of Palaeontology, Vienna, Austria. 2Zürichstrasse 58, 8607 Aathal-Seegräben/ZH, Switzerland.

Email: tuertscher.julia@gmail.com

The tiger shark Galeocerdo cuvier, one of the largest predatory sharks in today’s oceans, has distinctively notched and serrated teeth, which allow it to cut out pieces of its prey and even crack open shells of sea turtles. It is the only extant species of this genus and has a fossil record extending back at least into the late Miocene (~5 Ma). The fossil record of the genus, however, reaches back even further into the early Eocene (~56 Ma). During the last 200 years, more than sixty fossil species were described based on isolated teeth, with some species even based upon a single tooth. About twenty of these species are still considered valid, among them the well-known Miocene tiger shark Galeocerdo aduncus.

Theories about the origin of the living tiger shark, Galeocerdo cuvier, his direct ancestors and closest extinct relatives were frequently discussed in the past years, but the history of this exceptional shark still remains obscure.

We compared nearly five hundred teeth of several tiger shark species using geometric morphometrics to investigate significant morphological variations and to verify the validity of the examined species. The clustering of the specimens on the morphospace clearly demonstrated the presence of different species, as well as an ontogenetic shift of tooth morphology in extant juvenile and adult tiger sharks. Our results provide new information about the ambiguous evolutionary history of the tiger shark and suggest that the origin of the extant species Galeocerdo cuvier lies back more than twice as long as previously thought.

These data greatly augment our understanding of the complex evolutionary history of this iconic shark lineage, which has been very successful for the last 56 million years but is facing many threats today due to human activities and therefore should be a priority target for future conservation efforts.

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European Elasmobranch Association

22

nd

annual conference

12 – 14 October, Peniche – Portugal

Book of Abstracts

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European Elasmobranch Association

22

nd

annual conference

12 – 14 October, Peniche – Portugal

Organized by

Associação Portuguesa para o Estudo e Conservação de

Elasmobrânquios & Escola Superior de Turismo e

Tecnologia do Mar do Instituto Politécnico de Leiria.

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