Abstract
Microremains from the Lower Cretaceous Phu Phan Thong locality, Nong Bua Lam Phu Province, northeastern Thailand, yielded ten tooth morphotypes of the freshwater shark genus Isanodus, which allow the revision of this genus. Two new morphotypes assigned to anterolateral and posterolateral teeth possess shared characters with anterior and posterior teeth of Isanodus paladeji whereas its former anterolateral and posterolateral teeth appear to belong to a new species, Isanodus nongbualamphuensis sp. nov. The pattern of ornamentation in some teeth of I. paladeji and I. nongbualamphuensis is quite similar to that observed in the genus Heteroptychodus, suggesting these two genera are closely related.
Kurzfassung
Mikro-Überreste aus der Unterkreide von Phu Phan Thong Ort, Nong Bua Lam Phu Province, Thailand, ergaben zehn Zahnmorphotypen der Süßwasser Hai-Gattung Isanodus, die eine Revision dieser Gattung erlauben. Zwei neue Morphotypen besitzen gemeinsame Merkmale mit vorderen und hinteren Zähnen von Isanodus paladeji und werden als anterolaterale oder posterolaterale Zähne betrachtet. Die Zähne, die früher als anterolaterale oder posterolaterale Zähne von I. paladeji identifiziert wurden, scheinen in der Tat zu einer neuen Art, Isanodus nongbualamphuensis sp. nov., zu gehören. Zwei Morphotypen können nicht zu einer dieser beiden Arten gehören und zeigen die Anwesenheit einer dritten Art. Das Ornamentations-Muster in einigen Zähnen von I. paladeji und I. nongbualamphuensis sp. nov. ist ziemlich ähnlich dem in der Gattung Heteroptychodus beobachteten, was eine eng Verwandtschaft dieser beiden Gattungen andeutet.
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Acknowledgments
The authors would like to thank Dr. Varavudh Suteethorn for his support and for granting us access to the PRC collection. We also thanks Nual-Anong Narkkong for her help with the SEM at Mahasarakham University, and Chalida Laojumpon for access to Kut Island’s collection. This work was supported by a CHE-PhD-THA scholarship, and GC’s work was funded by the Carlsberg Foundation and carried out under National Research Council of Thailand authorizations 126/51 and 102/54. We would like to thank all individuals who helped during this work, including Utumporn Deesri, Paladej Srisuk, Suravech Suteethorn, Atiwut Patanapitaksakul, Siripa Phusangthong, Saithong Sila, Kamollak Wonggo and Dr. Jolyon Dodgson. Special thanks are also due to Serge Legendre and Jürgen Pöllerspock for their help with the translation of the abstract in German. Finally, comments on the manuscript by Charlie Underwood and Jürgen Kriwet greatly enhanced its quality.
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An erratum to this article can be found at http://dx.doi.org/10.1007/s12542-016-0323-7.
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Khamha, S., Cuny, G. & Lauprasert, K. Revision of Isanodus paladeji (Elasmobranchii, Hybodontiformes) from the Lower Cretaceous of Thailand. PalZ 90, 533–541 (2016). https://doi.org/10.1007/s12542-015-0282-4
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DOI: https://doi.org/10.1007/s12542-015-0282-4