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.
Titanosaur
Titanosaurs were widespread. In December 2011, Argentine scientists announced titanosaur fossils had been found on Antarctica—meaning that titanosaur fossils have been found on all continents. Four well-preserved skeletons of a titanosaur species were found in Italy, a discovery first reported on 2 May 2006. They are especially numerous in the southern continents (then part of the supercontinent of Gondwana). Australia had titanosaurs around 96 million years ago: fossils have been discovered in Queensland of a creature around long. Remains have also been discovered in New Zealand. One of the largest ever titanosaur footprints was discovered in the Gobi desert in 2016. One of the oldest remains of this group was found from the Valley of the Dinosaurs, Paraíba state of Brazil, representing a 136-million-year-old subadult individual.