Fossils Content

Taking the Earth’s Temperature Over the Past 485 Million Years

Andy Fell — September 19, 2024 - 10:36am

Palm trees in Alaska, crocodiles in Wyoming: Fossils show that Earth’s temperature has changed over hundreds of millions of years. Now a new study co-led by the Smithsonian and the University of Arizona, with Professor Isabel Montañez of the ��ϲ��Ͽ� Davis Department of Earth and Planetary Sciences, has produced a curve of global mean surface temperatures over the past 485 million years. The new curve, published Sept. 19 in Science, reveals that Earth’s temperature has varied more than previously thought as life has diversified, populated land and endured multiple mass extinctions.

Slimming Down a Colossal Fossil Whale

Andy Fell — February 29, 2024 - 2:23pm

A 30 million year-old fossil whale may not be the heaviest animal of all time after all, according to a new analysis by paleontologists at ��ϲ��Ͽ� Davis and the Smithsonian Institution. The new analysis puts Perucetus colossus back in the same weight range as modern whales and smaller than the largest blue whales ever recorded. The work is published Feb. 29 in PeerJ.

Molecular Fossils Shed Light on Ancient Life

Andy Fell — December 07, 2023 - 9:00am

Paleontologists are getting a glimpse at life over a billion years in the past based on chemical traces in ancient rocks and the genetics of living animals. Research published Dec. 1 in Nature Communications combines geology and genetics, showing how changes in the early Earth prompted a shift in how animals eat.

Reanalysis Shows Dinosaurs Not So Warm-Blooded

Andy Fell — September 07, 2023 - 12:09pm

Modern birds and mammals are “warm-blooded” or endothermic, maintaining a constant body temperature and generating heat internally, while reptiles rely on heat from their surroundings. It has been known for some time that at least some dinosaurs, including the direct ancestors of modern birds, were also endotherms.

Dating the Dinosaur Pompeii

Andy Fell — April 16, 2021 - 8:39am

Northeastern China is home to one of the world’s most remarkable collections of dinosaur fossils. The Jehol biota contains fossils of dinosaurs, plants, insects and fish, many of them preserved in unusual detail with traces of skin and feathers, dating back to the Early Cretaceous period 101 to 143 million years ago.

Ichthyosaur’s Last Meal Is Evidence of Triassic Megapredation

Andy Fell — August 20, 2020 - 7:53am

Some 240 million years ago, a dolphinlike ichthyosaur ripped to pieces and swallowed another marine reptile only a little smaller than itself. Then it almost immediately died and was fossilized, preserving the first evidence of megapredation, or a large animal preying on another large animal. The fossil, discovered in 2010 in southwestern China, is described in a paper published Aug. 20 in the journal iScience.

Earliest Ichthyosaur Munched on Shellfish

Andy Fell — May 11, 2020 - 8:01am

The ichthyosaurs were sleek, dolphin-like marine reptiles that roamed the oceans while dinosaurs ruled on land. But the earliest known member of the group was a short, seal-like animal that could likely pull itself on to land. Now scanning of that animal’s skull shows that it likely fed on hard-shelled animals such as shellfish and crabs. The appearance of similar teeth in other ichthyosaurs gives insight into how these animals were evolving in the wake of the mass extinction at the end of the Permian era, 250 million years ago.

Researchers Describe New Reptile Platypus From the Early Triassic

Andy Fell — January 24, 2019 - 4:11pm

No animal alive today looks quite like a duck-billed platypus, a semi-aquatic, egg-laying mammal hailing from eastern Australia. But about 250 million years ago, something very similar swam the shallow seas in what is now China, finding prey by touch with a cartilaginous bill. The newly discovered marine reptile Eretmorhipis carrolldongi from the lower Triassic period is described in the journal Scientific Reports Jan. 24.

Reconstruction of Ancient Chromosomes Offers Insight Into Mammalian Evolution

Andy Fell — June 21, 2017 - 11:50am

What if researchers could go back in time 105 million years and accurately sequence the chromosomes of the first placental mammal? What would it reveal about evolution and modern mammals, including humans?

In a study published this week in Proceedings of the National Academy of Sciences, researchers have gone back in time, at least virtually, computationally recreating the chromosomes of the first eutherian mammal, the long-extinct, shrewlike ancestor of all placental mammals.

Moroccan Fossils Show Human Ancestors’ Diet of Game

Andy Fell — June 07, 2017 - 10:07am

New fossil finds from the Jebel Irhoud archaeological site in Morocco do more than push back the origins of our species by 100,000 years. They also reveal what was on the menu for our oldest-known Homo sapiens ancestors 300,000 years ago: Plenty of gazelle meat, with the occasional wildebeest, zebra and other game and perhaps the seasonal ostrich egg, says Teresa Steele, a paleoanthropologist at the University of California, Davis, who analyzed animal fossils at Jebel Irhoud.