In a new PLOS ONE study, Guntupalli Prasad and colleagues announce the discovery of what is thought to be the first Jurassic ichthyosaur found in India. The 5.5-meter-long marine reptile likely ate shelled marine animals known as ammonites and other crunchy prey. The authors believe that its unusually complete skeleton may provide insights into ichthyosaur diversity and evolution in the oceans that once covered the Kachchh region of India. To learn more about this research, I interviewed Prasad via email.
Prasad (center) poses with members of his field crew behind the Kachchh ichthyosaur
What first drew you to paleontology?
GP: I was initially inspired by Professor Ashok Sahni, the well-known vertebrate paleontologist of India. Since my Ph.D., I have been pursuing research on fossilized vertebrates that colonized India during its northward journey: my most exciting find to date has been the discovery of the first Cretaceous (66-million-year-old) mammals from India. Surprisingly, these mammals appear closely related to similar European and African fossils, even though the Indian subcontinent was an island at this time.
Ichthyosaurs lived alongside dinosaurs but were in fact lizards. Tell us a little about when they lived, and what Earth was like when they were alive.
GP: Ichthyosaurs or “fish lizards” resembled modern dolphins and whales and lived between 250 and 90 million years ago. The Earth, initially assembled into a single supercontinent, Pangaea, was at that time breaking up into Laurasia and Gondwanaland. Ichthyosaurs lived in the oceans in a warm and humid climate. Their main marine competitors were plesiosaurs, another group of marine reptiles, and sharks. While the dinosaurs were dominating the land, the pterosaurs, flying reptiles, were the rulers of the air.
You describe a new ichthyosaur found in the Kachchh region of Gujarat, India. Why was the location of this fossil surprising? What might it tell us about global ichthyosaur dispersal?
GP: Vertebrate fossils are rare from the Kachchh region, and we were expecting only bone fragments from this area. So, to find a near-complete skeleton is surprising as well as exciting. The discovery of this ophthalmosaurid ichthyosaur, which is widely known from Europe, points to the possibility that ichthyosaurs may have moved between Europe, western India, Madagascar and South America — a process known as faunal exchange
What did you learn about this ichthyosaur’s appearance and its likely lifestyle?
GP: Based on the preserved length of the Kachchh skeleton (3.6 meters), and factoring in its missing front and tail parts, we estimate its total length to be 5.5 meters. We could infer from wear patterns on its teeth that this ichthyosaur was a top-tier predator that fed on hard and abrasive food material, including marine molluscs (ammonoids and belemnites), fish and possibly other marine reptiles.
Which of your findings was most interesting or surprising to you?
GP: Initially, we couldn’t find any skull for the Kachchh ichthyosaur, and were forced to conclude that the skull and the jaws had not been preserved. But while making protective plaster jackets ready for transportation of the skeleton, we dug below its front part and were surprised and delighted to come across part of the jaw vertically embedded in the rocks. This was an especially useful discovery because the teeth we found offered insights into the ichthyosaur’s diet.
What are the next steps for your research, and what do you hope your findings might lead to?
GP: In the coming years, we plan to carry out extensive field exploration in the Kachchh region to find more ichthyosaur fossils and to search for other marine reptiles. We hope that our find may lead to renewed interest in vertebrate fossil research in this region, which could bring new discoveries to light.
Research Article: Prasad GVR, Pandey DK, Alberti M, Fürsich FT, Thakkar MG, Chauhan GD (2017) Discovery of the first ichthyosaur from the Jurassic of India: Implications for Gondwanan palaeobiogeography. PLoS ONE 12(10): e0185851. https://doi.org/10.1371/journal.pone.0185851
Images Credits: Prasad et al., 2017; Guntupalli Prasad