Global extinction event led to evolution of weapon-like teeth in marine reptiles – India Today

The discovery of a new fossil from central Colombia could shed light on the evolution of marine reptiles. The well preserved metre-long skull discovered by researchers from Canada, Colombia, and Germany is one of the last surviving ichthyosaurs ancient animals that look like living swordfish.

The marine animal has been named Kyhytysuka, which translates to "the one that cuts with something sharp" in an indigenous language from the region in central Colombia where the fossil was found.

The animal shows the evolution of a unique arsenal of teeth to devour its prey against other ichthyosaurs that had small, equally sized teeth for feeding on small prey. The study of the marine fossil published in the Journal of Systematic Palaeontology states that the discovery has helped in a better understanding of the anatomy of the marine reptile.

Hans Larsson, Director of the Redpath Museum at McGill University and a lead author of the study said that the animal evolved a unique dentition that allowed it to eat large prey. Whereas other ichthyosaurs had small, equally sized teeth for feeding on small prey, this new species modified its tooth sizes and spacing to build an arsenal of teeth for dispatching large prey, like big fishes and other marine reptiles, he added.

Skeleton of Kyhytysuka compared to a human for scale. Known bones are shown in white. Credit: (Photo: Dirley Corts)

Researchers said that they decided to name it Kyhytysuka, to honour the ancient Muisca culture that existed in the region where the fossil was found.

In a bid to clarify the evolution of the unique animal, researchers compared it with other Jurassic and Cretaceous ichthyosaurs and defined a new type of ichthyosaur. They concluded that the species comes from an important transitional time during the Early Cretaceous period when the Earth was coming out of a relatively cool period, had rising sea levels, and the supercontinent Pangea was splitting into northern and southern landmasses.

In a release by McGill University, researchers said that there was also a global extinction event at the end of the Jurassic that changed marine and terrestrial ecosystems.

Dirley Corts working with the skull of Kyhytysuka. (Photo: Dirley Corts)

We are discovering many new species in the rocks this new ichthyosaur comes from. We are testing the idea that this region and time in Colombia was an ancient biodiversity hotspot and are using the fossils to better understand the evolution of marine ecosystems during this transitional time," Dirley Corts, a graduate student under the supervision of Hans Larsson and Carlos Jaramillo of the Smithsonian Tropical Research Institute said.

Researchers concluded that the new discovery shakes up the evolutionary tree of ichthyosaurs and "lets us test new ideas of how they evolved.

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Global extinction event led to evolution of weapon-like teeth in marine reptiles - India Today