What exactly are Ichthyosaurs?
Ichthyosaurs were marine reptiles that lived in oceans around the world for the majority of the Mesozoic Age, also known as the Age of Reptiles, which lasted from 250 million to 66 million years ago when dinosaurs were wiped out by a meteor strike.Why is an ichthyosaur not a dinosaur?Dinosaurs were archosaurs, which had a more upright gait than other reptiles and a skull opening in front of their eyes (the antorbital fenestra). They were Avemetatarsialians rather than Crurotarsians, and they were distinguished by their more birdlike ankles than other archosaurs (the group of archosaurs that includes modern crocodilians and a host of extinct forms). They were dinosauromorphs rather than pterosauromorphs within the Avemetatarsalians, which makes sense. So neither pterosaurs nor the various crocodile-like archosaurs that were once so common were dinosaurs.Plesiosaurs and ichthyosaurs are not archosaurs. They are diapsids, like archosaurs, with two openings or fenestrae in the back of the skull, but they belong to the same group as most reptiles. Ichthyosaurs are as closely related to lizards and snakes as they are to dinosaurs (though probably not more so).Are ichthyosaurs still alive?If you can find this name, ichthyosaurs, somewhere, you should also be able to find out that they died out 90 million years ago, to the best of our knowledge (dinosaur experts' knowledge).What killed the ichthyosaur?There are numerous reasons for dinosaur extinction. One of the most widely accepted theories involves a massive meteor.- The Yucatan Peninsula was hit by a meteor 65 million years ago. The mass extinction was caused by this meteor.- It had a diameter of 150 kilometres and an impactor diameter of 10–15 kilometres. It was 20 kilometres deep, so you can imagine how severe the extinction was.- Massive clouds of dust formed after the meteor hit, blocking the sun and lowering the temperature. It also caused major disruptions between the crusts, resulting in seismic activity such as tsunamis and earthquakes.- Dinosaurs, as we know, we're not adapted to colder temperatures and died as a result.- Birds, mammals, reptiles, and other small animals flourished, evolving into what they are today. As a result, mosasaurs, ammonites, ichthyosaurs, and pterosaurs became extinct.However, the extinction of the K-PG resulted in the rise of mammals. In the absence of apex predators and other animals, mammals evolved slowly and eventually dominated the planet. Birds, on the other hand, survived the dinosaurs. Raptors, or maniraptorans, evolved into birds and flew around the world. Crocodilians, lizards, turtles, and other reptiles managed to survive.What was the largest ichthyosaur?The largest officially described dinosaur is a Shastasaurus species from British Columbia, which grew to be around seventy feet long and weighed around fifty or sixty tonnes. That compares them to a sperm whales.There have been rumours of larger ones, but I haven't heard anything from reliable sources. Read the full article