the Middle Jurassic. This might be a result of the poor fossil record in general of this epoch. The strata of the Late Jurassic seem to indicate that a further decrease in diversity had taken place. From the Middle Jurassic onwards, almost all ichthyosaurs belonged to the thunnosaurian clade Ophthalmosauridae. Represented by the Ophthalmosaurus and related genera, they were very similar in general build to Ichthyosaurus. The eyes of Ophthalmosaurus were huge, and these animals likely hunted in dim and deep water. However, new finds from the Cretaceous indicate that ichthyosaur diversity in the Late Jurassic must have been underestimated. Cretaceous Traditionally, ichthyosaurs were seen as decreasing in diversity even further with the Cretaceous, though they had a worldwide distribution. All fossils from this period were referred to a single genus: Platypterygius. This last ichthyosaur genus was thought to have become extinct early in the late Cretaceous, during the Cenomanian about 95 million years ago. The ichthyosaurs thus would have disappeared much earlier than other large Mesozoic reptile groups that generally survived until the end of the Cretaceous. Two major explanations were given for this. Firstly, it could have been a matter of chance. The second explanation had the extinction as caused by competition. Less hydrodynamically efficient animals, such as the Mosasauridae and long-necked plesiosaurs, flourished. The ichthyosaurian overspecialisation could be a contributing factor to their extinction, possibly being unable to 'keep up' with the fast-swimming and highly evasive new teleost fish, which had become dominant at this time, against which the sit-and-wait ambush strategies of the mosasaurids proved superior. This model thus emphasised evolutionary stagnation, the only innovation shown by Platypterygius being its ten fingers. Recent studies, however, show that ichthyosaurs were actually far more diverse in the Cretaceous than previously thought. Fragments referred to Platypterygius in fact represented diverse species. In 2012, at least eight lineages spanned the Jurassic-Cretaceous boundary, among them Acamptonectes, Sveltonectes, Caypullisaurus, and Maiaspondylus. In 2013, a Cretaceous basal thunnosaurian was revealed: Malawania. Indeed, likely a radiation during the Early Cretaceous occurred due to an increase of coastlines when the continents further broke up. The demise of the ichthyosaurs has recently been described as a two-step process. A first extinction event in the beginning of the Cenomanian eliminated two of the three ichthyosaur feeding guilds then present, the 'soft-prey specialists' and the 'generalists', leaving only an apex predator group, which probably was not particularly specialized.