The oldest Gondwanan record of durophagous shark Strophodus Agassiz, 1838 (Hybodontiformes) from the Kachchh Basin, western India

ABSTRACT

The hybodont sharks were one of the most dominant groups of chondrichthyans during the Mesozoic. The genus Strophodus was one of the most successful hybodont sharks that covered marine to coastal, occasionally high salinity niches in the pantropical basins and had adapted an unique dentition for their durophagous diet. Although the European basins are enriched with the genus fossil record, the distribution in the Gondwana basins is scarce and patchy. The present study is the first report of the genus Strophodus from the Kachchh Basin and the oldest record from Gondwana. Three taxa are recorded here, viz. S. atlasensis, S. magnus and S. sp. from the ?Early to Middle Jurassic succession of Kachchh Basin that lived in the nearshore to an estuarine environment with abundant macrobenthic fauna, such as bivalves, brachiopods, gastropods and so on. The current study sheds light on the palaeoecology and palaeobiogeography of the genus. The new insights from the present work contribute to the poorly known chondrichthyan fauna from the Kachchh Basin and Gondwana as well.

KEYWORDS:

• Kachchh
• Jurassic
• Chondrichthyes
• Gondwana
• durophagous diet
• palaeobiogeography

Acknowledgments

The authors would like to acknowledge K. Chaskar (KSKV Kachchh University, India), A. Chakraborty and S. Ganguly (Indian Institute of Technology Bombay, India) for their field assistance and BSF Amrapar, Khadir for their hospitality during the field visits. SB would also like to extend his gratitude to J. Pollerspöck (Bavarian State Collection of Zoology, München, Germany) and M. Szabó (Hungarian Natural History Museum, Hungary) for providing old literature. SB is thankful to the Indian Institute of Technology Bombay for the postdoctoral fellowship. AN would like to acknowledge the Council of Scientific and Industrial Research (CSIR) for their doctoral scholarship (JRF File No. 09/0087(13891)/2022-EMR-I). A. Thakkar is thanked for providing the palaeo reconstruction of Strophodus (Figure 9) and A. Sarkar for the language assistance of the initial draft. We are also thankful to the Indian Institute of Technology Bombay, Mumbai, India and KSKV Kachchh University, Bhuj, India, for their infrastructural and administrative help. The authors would like to thank G. Dyke, A. Heckert and M. S. Bhat, for their insightful comments and suggestions.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The work was supported by the Indian Institute of Technology Bombay [RD/0522-IRCCSH0/028].