Her life fell within the Eocene Epoch
, a time when the blueprints for modern mammals were being established.
The fossil was recovered from sedimentary rock strata that were deposited in the ancient lake roughly 55 million years ago, during the early part of the Eocene epoch
Global warming kicked off the Eocene epoch
about 55 million years ago, but new research shows that this greenhouse phase did little for North America's plants.
It lived alongside other herbivorous and carnivorous mammals during the Eocene epoch
The younger group hails from the Eocene epoch
, 53 million years ago, during which temperatures reached a peak.
The early Eocene Epoch
(50 million years ago) was about as warm as the Earth has been over the past 65 million years, since the extinction of the dinosaurs," Linda Ivany, associate professor of earth sciences said.
The planet was warmer, however, during the Eocene epoch
, which may explain how smaller animals could have flourished then, says Bloch.
Consisting of rock layers formed between the Jurassic Period (200-145 million years ago) and the more recent Eocene Epoch
(55-34 million years ago), the Hazarchishma Natural Bridge was carved over millennia by the once flowing waters of the now dry Jawzari Canyon.
The species of foraminifera suggests that the whale lived during the early Eocene epoch
, whereas Pakicetus fossils have come from middle Eocene rocks.
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
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.
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.
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.
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.
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.