'Rare discovery': New species of hybodont shark of Jurassic age found in Rajasthan's Jaisalmer

In a rare discovery, teeth of new species of hybodontshark of Jurassic age have been reported for the first time from Rajasthan's Jaisalmer, the Ministry of Mines informed on Wednesday. The discovery was made by a team of officers comprising Krishna Kumar, Pragya Pandey, Triparna Ghosh and Debasish Bhattacharya from the Geological Survey of India (GSI), Western Region, Jaipur. 

Finding has been published in Historical Biology, a Journal of Palaeontology of International repute, in its August, 2021, 4th issue. Prof. Dr. Sunil Bajpai, Head of the Department, Department of Earth Sciences, IIT Roorkee, who is a co-author of this publication, played a significant role in the identification and documentation of this important discovery, the ministry said.

Hybodont sharks have been reported for the first time from the Jurassic rocks (approximately, between 160 and 168 million-years-old) of the Jaisalmer region of Rajasthan, said Krishna Kumar, senior geologist, Palaeontology Division. 

Hybodonts, an extinct group of sharks, was a dominant group of fishes in both marine and fluvial environments during the Triassic and early Jurassic time. 

However, hybodont sharks started to decline in marine environments from the Middle Jurassic onwards until they formed a relatively minor component of open-marine shark assemblages. 

Hybodonts finally became extinct at the end of the Cretaceous time 65 million years ago.

Significantly, the newly discovered crushing teeth from Jaisalmer represents a new species named by the research team as Strophodusjaisalmerensis. The genus Strophodus has been identified for the first time from the Indian subcontinent and is only the third such record from Asia, the other two being from Japan and Thailand. 

The new species has recently been included in the Shark references.com, an international platform operating in association with International Union for Conservation of Nature (IUCN), Species Survival Commission (SSC), and Germany.

According to the ministry, this discovery marks an important milestone in the study of Jurassic vertebrate fossils in the Jaisalmer region of Rajasthan, and it opens a new window for further research in the domain of vertebrate fossils.

The GSI was set up in 1851 primarily to find coal deposits for the Railways. Over the years, GSI has not only grown into a repository of geo-science information required in various fields in the country but has also attained the status of a geo-scientific organisation of international repute. Its main functions relate to creating and updating of national geoscientific information and mineral resource assessment. 

These objectives are achieved through ground surveys, air-borne and marine surveys, mineral prospecting and investigations, multi-disciplinary geoscientific, geo-technical, geo-environmental and natural hazards studies, glaciology, seism tectonic study, and carrying out fundamental research.