mosasauroids

Mosasauroids are an extinct lineage of marine reptiles that lived during the Late Cretaceous period, from about 100 to 66 million years ago. They were highly successful predators and evolved to fill ecological niches similar to modern whales and sharks. These reptiles were not dinosaurs, but rather a specialized group of lizards. Mosasauroids had streamlined bodies, powerful tails, and large jaws armed with rows of sharp teeth, adaptations for an aquatic lifestyle.

Their fossil record is primarily found in marine sediments worldwide, indicating a global distribution. Over time, mosasauroids diversified into a wide range of sizes and forms, from relatively small species to the colossal Mosasaurus, which could reach lengths of over 15 meters. Their limbs evolved into paddle-like flippers, and their bodies became more elongated. They likely gave birth to live young, as evidenced by fossil discoveries of pregnant females.

The extinction of mosasauroids, along with many other species, occurred at the end of the Cretaceous period during the K-Pg extinction event. Their demise marked the end of a significant era for marine reptiles. Studies of their anatomy and relationships with other lizards continue to provide insights into reptilian evolution and the dynamics of ancient marine ecosystems.