Closing the corridor – search for archaeocete fossils (Mammalia: Cetartiodactyla) in the Eocene deposits of Kangan area (Gulf region, Iran)
Final Report Abstract
In the Kangan region, Persian Gulf, Iran, fossilised bones of archaeocete cetaceans, pansirenians and other vertebrate remains (predominantly shark teeth) were found during previous field work in the deposits of the Pabdeh Fm of middle/late Eocene age. Findings from Iran could be of great importance for the interpretation of the phylogeny and development of the paraphyletic archaeocetes and could extend our knowledge regarding the evolution of cetaceans. The focus of the project was to discover, collect, prepare, describe, and analyse additional fossil finds. Cooperation partners, the Islamic Azad University in Esfahan and the Geologial Survey and Mineral Exploration of Iran, initially enabled access to the localities and collections, so that prospection and collecting activities and studies were ensured. Research trips, including field and collection work, brought an assemblage of vertebrate remains of a typical coastal epipelagic fauna to light. Finally, 1,323 vertebrate remains could be studied, 86% of all items belong to elasmobranchs, predominantly isolated teeth. The rest belong to fragmentarily preserved bone remains of the axial skeleton of the marine mammals and crocodylomorphs. Unfortunatey, the low thickness of the bone bearing member did not lead to expected articulated finds. Political problems arose during the research period that stood and still stand in the way of the implementation of the actual project idea. They ended up in restrictions that made it impossible to continue. The consequence was that it was no longer allowed to work in the Kangan region. From Tehran, the previously granted research permission was revoked and, subsequently, publishing material from there was prohibited. To not endanger close colleagues and collaborators in Iran, yet existing results will not be published. In order to “rescue” the Iran studies, two side projects were carried out. One meant the continuation of the studies on a mysticete skeleton from the late Tortonian/Messinian of the Coastal Makran in Baluchestan near the Pakistan border, a specimen which shows cranial morphological similarities with those of the living blue whale. With additional support of the Ministry of Science, Research and Technology in Iran the complete recovery of the skeleton and its transportation to the museum in Chabahar could be realised. A second side project is still in progress. It deals with the diagenetic and taphonomic interpretations based of (pan-)sirenian rib remains using isotopes (O, Sr) and rare earth elements including samples of the Iranian sites of the Kangan area (see above) and the Daryai region (Mishan Fm, early Miocene). Polished bone sections were used and an insideoutside mapping of element distribution. After preliminary studies, the diagenetic alteration of bone apatite result in overall higher δ18O values but in contrast to δ18O, the 87Sr/86Sr values of the Iranian bones suggest no significant alteration. The samples from Kangan and Daryai reveal homogeneous rare earth element patterns, with an anomalous relative enrichment of Lanthanum. Such pattern is characteristic for fossils from open ocean and epicontinental waters indicating only minor diagenetic alteration.
Publications
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Preliminary report on a late Tortonian/Messinian balaenopterid cetacean (Mammalia, Mysticeti) from Sistan and Baluchestan Province (Iran). Geopersia, 9(1): 65–79.
Hampe, O., Hairapetian, V., Mirzaie Ataabadi, M. & Orak, Z.
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Another piece in the puzzle: Eocene sea cow remains found under unusal circumstances – Prototherium ausetanum (Sirenia, Dugongidae) from Catalonia (Spain). In: Loch, C., Valenzuela Toro, A., Pardo-Pérez, J.M., Buono, M.R. amd Gutstein, C.S. (eds.) 9th International Meeting on the Secondary Adaptation of Tetrapods to Life in Water Virtual Meeting, Chile, April 19-23, 2021, Abstract Book, p. 62.
Hampe, O., Voss, M., Mahlow, K. & Vilanova, J.C.
