Origin of marine reptiles pushed back by discovery of oldest-known ichthyosaur

According to the scientific textbooks, reptiles first ventured into the open sea in the wake of the end-Permian mass extinction, which occurred 251.9 million years ago.

(This cataclysmic event — dubbed “the Great Dying” — is thought to have been triggered by rising global temperatures induced by volcanically-released carbon dioxide, and resulted in the loss of a whopping 81 per cent of marine species.

At the same time, however, the mass extinction paved the way for the ascent of the dinosaurs, who would dominate until the Chixculub asteroid impact 66 million years ago.)

It had been thought that land-based reptiles with walking legs moved to occupy shallow coastal environments to take advantage of predator niches left vacant by the Great Dying.

Over time, experts thought, these early amphibious reptiles would have become more efficient at swimming — evolving their limbs into flippers; developing a more streamlined, “hydrodynamic” body shape; and severing their last tie to the land by giving birth to live young, rather than need to lay eggs on solid ground.

The new fossils unearthed from Spitsbergen, however, are throwing doubt on this account of how marine reptiles first evolved.

Article source: https://www.express.co.uk/news/science/1746219/fossils-origin-marine-reptiles-pushed-back-exciting-discovery-norway-ichthyosaur