An enduring paleontology mystery could have been finally solved. It is the baffling case of the demise of a very successful group of dolphin-like marine reptiles known as ichthyosaurs that thrived in the oceans on the planet for over 150 million years.

On Tuesday, scientists credited the 94 million years ago extinction to both global warming and their own incapability of evolving fast enough.

The study is the most comprehensive examination so far of their disappearance data, undercut early notions that suggested that ichthyosaurs were declining for tens of millions of years and had been defeated by other predators like terrifying ocean-going lizards known as mosasaurs that had just started coming on the scene. In fact, the research showed that the huge mosasaurs appeared just after the extinction of ichthyosaurs.

Paleontologist Valentin Fischer of Belgium's University of Liege said that they have discovered that ichthyosaurs were quite diversified towards the end of their reign. Fischer noted that many species with different body shapes and ecological niches used to exist, though the evolution of ichthyosaur had become comparatively stagnant.

The University of Oxford paleontologist, Roger Benson, added that their data concludes that the extinction was unexpected, not a gradual process.

Ichthyosaurs came into being nearly 248 million years back, becoming main players in marine ecosystems when the land was under dinosaurs’ rule.

They had a streamlined, dolphin-like body design. They were very quick, efficient, air-breathing swimmers having muscular flippers. They had vertical tail flukes similar to sharks, not horizontal akin dolphins and whales.

They used to have extraordinary big eyes for spotting prey such as fish and squid in deep or turbid waters. They used to give birth to live babies rather than laying eggs.