Mosasaur
Mosasaurs (from Latin "Mosa" meaning the 'Meuse river', and Greek σαύρος "sauros" meaning 'lizard') are an extinct group of large marine reptiles containing 38 genera in total. Their first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764. Mosasaurs probably evolved from an extinct group of aquatic lizards known as aigialosaurs in the Early Cretaceous. During the last 20 million years of the Cretaceous period (Turonian-Maastrichtian ages), with the extinction of the ichthyosaurs and pliosaurs, mosasaurs became the dominant marine predators. They became extinct as a result of the K-Pg event at the end of the Cretaceous period, about 66 million years ago.
Evolution of lemurs
The second major episode of diversification occurred during the Late Miocene, approximately 8 to 12 mya, and included the true lemurs ("Eulemur") and the mouse lemurs ("Microcebus"). This event coincided with the beginning of the Indian monsoons, the last major change in climate to affect Madagascar. The populations of both the true lemurs and mouse lemurs were thought to have diverged due to habitat fragmentation when humans arrived on the island roughly 2,000 years ago. Only recently has molecular research shown a more distant split in these genera. Most surprising were the mouse lemurs, a group which is now thought to contain cryptic species, meaning they are indistinguishable from each other based solely on appearance. In contrast, true lemurs are easier to distinguish and exhibit sexual dichromatism. Studies in karyology, molecular genetics, and biogeographic patterns have also assisted in understanding their phylogeny and diversification. Although the divergence estimates for these two genera are imprecise, they overlap with a change to a wetter climate in Madagascar, as new weather patterns generated monsoons and likely influenced the plant life.