Evolutionary Dynamics of Eocene Antarctic Fishes
Primary Investigator: Univ.-Prof. Dr. Jürgen Kriwet
The Palaeogene was one of the most important time intervals in global climatic developments characterized, inter alia, by a late Eocene transition from the greenhouse world to icehouse conditions (ca. 49-34 Ma). The final cooling phase across the Eocene-Oligocene (E-O) boundary (ca. 33.7 Ma) resulted in the thermal isolation of Antarctica and the establishment of large Antarctic ice sheets. These climatic changes, which persisted into the earliest Oligocene resulted in major biotic turnovers in marine and terrestrial floras and faunas. Today’s Southern Ocean, which is delimited by the circum-Antarctic current (Antarctic Convergence) and the Antarctic continent, which is located within it are amongst the most remote and coldest places in the world and are both a key element in any model of Earth processes and climatic changes as well as a site of unique evolutionary traits related to the abiotic characters. The extant fish fauna within the Antarctic Convergence is striking in its low taxonomic diversity and high number of endemic taxa. The chondrichthyan fauna is extremely impoverished compared to the modern teleost fauna and this situation was similar in the Eocene.
The project aims at documenting and analysing the biotic effects of both short-term and long-term climate and palaeogeographic changes in Antarctica focusing on the taxonomic composition and diversity dynamics of Eocene Antarctic holocephalan and elasmobranchian fishes, which will serve as model organisms for evolutionary patterns in high-latitudes. Analysing originations, extinctions, diversity and diversification patterns and the palaeoecology of chondrichthyans in combination with extrinsic factors, which might influence evolutionary processes (e.g., climatic changes, palaeogeographic constellations) throughout the Eocene until the thermal and geographic isolation of Antarctica will not only provide deeper insights into adaptive and evolutionary patterns of high-latitude cartilaginous fishes but also into the development and probably the origin of the conspicuous modern-day Antarctic fish fauna with no resident holocephalans and sharks. Previous hypotheses stating, for instance, that there is a continuous diversity increase until the middle Eocene and that the absence of chondrichthyans in the uppermost Eocene of Antarctica is the result of the onset of the thermal isolation of the Antarctic continent will be tested with rigorous methodological approaches.
The ultimate goal is to present a comprehensive study of cartilaginous fish assemblages from the Eocene of Antarctica including revisions of previously published records. Integrated goals of this project are to (1) establish the taxonomic / systematic composition and stratigraphic distribution of cartilaginous fishes for each Eocene stratigraphic unit (here TELMs) of Antarctica, (2) establish the quality of their fossil record, (3) analyse the faunal relationships (Beta Diversity) of Eocene Antarctic chondrichthyan compositions, (4) study the underlying evolutionary dynamics such as origination, diversification, diversity fluctuation and extinction patterns of fishes in high latitudes during the Eocene and (5) reconstruct ecological patterns of Eocene Antarctic chondrichthyans.
- Univ.-Prof. Dr. Jürgen Kriwet (PI) Read more
- Dr. Andrea Engelbrecht (Predoctoral Researcher)
- Engelbrecht, A., Mörs, T., Reguero, M. & Kriwet, J. 2019. Skates and Rays (Elasmobranchii, Batomorphii) from the Eocene La Meseta Formation, Seymour Island, Antarctica. Historical Biology, 31: 1028-1044. Link to article
- Marramà, G., Engelbrecht, A., Mörs, T., Reguero, M. & Kriwet, J. 2018. The southernmost occurrence of Brachycarcharias (Lamniformes, Odontaspididae) from the Eocene of Antarctica provides new information about the paleobiogeography and paleobiology of paleogene sand tiger sharks. Rivista Italiana di
Paleontologia e Stratigrafia (Research In Paleontology and Stratigraphy) 124: 283-298. Link to article
- Engelbrecht, A., Mörs, T., Reguero, M. & Kriwet, J. 2017. New carcharhiniform sharks (Chondrichthyes, Elasmobranchii) from the early to middle Eocene, of Seymour Island, Antarctic Peninsula. Journal of Vertebrate Paleontology, 37: e1371724 (25 pages). Link to article
- Engelbrecht, A., Mörs, T., Reguero, M. & Kriwet, J. 2017. A new sawshark, Pristiophorus laevis, from the Eocene of Antarctica with comments on Pristiophorus lanceolatus. Historical Biology 29: 841-853 Link to article
- Engelbrecht, A., Mörs, T., Reguero, M. & Kriwet, J. 2017. Eocene squalomorph sharks (Chondrichthyes, Elasmobranchii) from Antarctica. The Journal of South American Earth Sciences.Historical Biology 78: 175-189. Link to article
- Schwarzhans, W., Mörs, T., Engelbrecht, A., Reguero, M. & Kriwet, J. 2017. Before the freeze: Otoliths from the Eocene of Seymour Island, Antarctica, reveal dominance of gadiform fishes (Teleostei). Journal of Systematic Palaeontology 15(2): 147-170. Link to article
- Engelbrecht, A., Mörs, T., Reguero, M. & Kriwet, J. 2017. Revision of Eocene Antarctic carpet sharks (Elasmobranchii, Orectolobiformes) from Seymour Island, Antarctic Peninsula. Journal of Systematic Palaeontology 15: 969-990.Link to article
- Kriwet, J., Engelbrecht, A., Mörs, T., Reguero, M. & Pfaff, C. 2016. Ultimate Eocene (Priabonian) chondrichthyans (Holocephali, Elasmobranchii) of Antarctica. Journal of Vertebrate Paleontology 36: e1160911 (19 pages).
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