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The Paleogene World

The Paleogene World. Holocene. Two-fold subdivision of Cenozoic: Paleogene , Neogene Previously , Cenozoic was divided into Tertiary (Paleocene-Pliocene) and Quaternary (Pleistocene-Holocene). Pleistocene. Neogene. Pliocene. Miocene. 24. Cenozoic. Oligocene. Paleogene. Eocene.

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The Paleogene World

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  1. The Paleogene World Holocene • Two-fold subdivision of Cenozoic: Paleogene, Neogene • Previously, Cenozoic was divided into Tertiary (Paleocene-Pliocene) and Quaternary (Pleistocene-Holocene) Pleistocene Neogene Pliocene Miocene 24 Cenozoic Oligocene Paleogene Eocene Paleocene 65 Earth History, Ch. 18

  2. Paleogene life • In marine realm, most groups that survived end-Cretaceous mass extinction recovered and diversified during Paleogene • Planktonic forams, calcareous nannos, mollusks, arthropods • Demise of giant marine reptiles opened the door to whales (Eocene) and giant sharks! Earth History, Ch. 18

  3. Whale evolution (Eocene-Holocene) Large, marine forms Terrestrial ancestor Earth History, Ch. 18

  4. Giant Eocene shark Modern shark jaws Earth History, Ch. 18

  5. Paleogene life • Other interesting newcomers to marine or marginal marine habitats: • Penguins (Eocene) • Pinnipeds (seals, sea lions, walruses) • Thought to have evolved from terrestrial ancestors in Paleogene time, but oldest fossils are Neogene Earth History, Ch. 18

  6. Paleogene life • On land………….. • Diversification and “modernization” of angiosperms • By early Oligocene time, half of all angiosperm genera were ones that still exist today • Origin of grasses • Earliest forms were sedge-like (discontinuous growth) • Late Oligocene-Neogene forms capable of continuous growth (able to withstand grazing pressure) Earth History, Ch. 18

  7. Paleogene life • Explosive adaptive radiation of mammals! • By Eocene time, most modern orders of mammals had appeared, including primates, carnivores and horses Cantius, climbing around in our family tree! Earth History, Ch. 18

  8. Eocene fossil bat Earth History, Ch. 18

  9. Earth History, Ch. 18

  10. Paleogene life • Other Eocene oddities………….. • Differentiation of ungulates (hoofed herbivores) • Even-toed (cattle, sheep, antelope, bison, pigs, camels, etc.) • Odd-toed (horses, tapirs, rhinos) • Appearance of elephants • Appearance of Diatryma (giant, flightless birds) Earth History, Ch. 18

  11. Hyracotherium (“Eohippus”)earliest horse (odd-toed) Dog-sized 4 toes 3 toes Earth History, Ch. 18

  12. Diacodexis(early even-toed ungulate) Earth History, Ch. 18

  13. Eocene elephants Earth History, Ch. 18

  14. Diatryma(stay away from this turkey!) 8 ft Earth History, Ch. 18

  15. Paleogene life • Many groups of mammals became extinct during Eocene time • Oligocene was noteworthy for: • Paraceratherium, largest land mammal ever (member of rhino family) • Origin of true monkeys • “Extinction” of horses throughout Eurasia • Expansion of big cats Earth History, Ch. 18

  16. Earth History, Ch. 18

  17. Paraceratherium 18 ft at shoulder Earth History, Ch. 18

  18. Aegyptopithecus(Oligocene monkey) Earth History, Ch. 18

  19. horses mostly absent in Old World Earth History, Ch. 18

  20. Dinictis(Oligocene saber-tooth cat) Earth History, Ch. 18

  21. Oligocene mammalian fauna of Nebraska & South Dakota Earth History, Ch. 18

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