This then raises two possibilities - a striking gap in the African fossil record prior to this period, which is unlikely as Northern Africa's Eocene sites have been well sampled over the past century, and no diversity of anthropoid fossils has yet been discovered that predates the new Libyan specimens or the second, more likely possibility - that several anthropoid species "colonized" Africa from another continent 39 million years ago-the middle of the Eocene epoch
The species of foraminifera suggests that the whale lived during the early Eocene epoch
, whereas Pakicetus fossils have come from middle Eocene rocks.
In her research, Katz developed important theories on one of the most recent and dramatic climate change events that have occurred in recent geologic history - the transition from the greenhouse climate of the Eocene epoch
to the "icehouse" or glacial conditions of the Oligocene epoch approximately 33.
During the Eocene epoch
, early relatives of rhinoceroses reached four and a half times the weight of an adult elephant, placing them among the largest land mammals ever.
Woodburne and co-authors Gregg Gunnell of the University of Michigan Museum of Paleontology and Richard Stucky of the Denver Museum of Nature and Science examined the records of ancient temperatures and information on the fossil plants and mammals that inhabited North America during the Eocene epoch
and found that diversity increased and declined with rising and falling temperatures.
Last week, Canadian and Russian geologists reported that two large bodies hit nearly simultaneously in the late Eocene epoch
, but they apparently did not decimate life.
Previous analyses of cores drilled in this region revealed ice-rafted debris dating back to the middle Eocene epoch
, prompting suggestions that ice appeared in the Arctic about 46 million years ago.
They appeared in the upper Triassic period, 210 million years ago, and they became extinct in the Eocene epoch
, a little more than 30 million years ago.