The Paleocene epoch was the first period of the Palaeogene, after the Mesozoic and before the Eocene. It lasted for about 8 million years and ended 58 +/- 4 mya. The Palaeocene was a period when a number of organic life forms, typical for the Cainozoic, began to form. The mammals included taeniodonts (extinct), tillodonts (extinct), the colugo, bats, Xenarthrans, rodents, hoofed mammals. The overall number of the mammal families grew from 20 to 50. The sauropsids were memorable by the extinct champsosaurs.