PALEO

paleo

Two ichthyosaurs become one

While dinosaurs ruled on land in the Mesozoic, dolphin-like marine reptiles called ichthyosaurs roamed the oceans. Paleontologists first described the genus in 1821 based on remains discovered in England, naming the first species Ichthyosaurus communis. The description of a second species, I. intermedius, followed in 1822. Although these two species were the earliest-known ichthyosaurs, they are also some of the most poorly understood, as their initial descriptions were based on limited remains.

22 Jun 2017

Rearranging the dinosaur family tree

Dinosaurs have long been grouped into two major clades — Ornithischia and Saurischia — largely based on the shapes of their hips. But new phylogenetic research is shaking up the dinosaur family tree, suggesting the traditional two-branch system needs reorganizing.

20 Jun 2017

Horses evolved to get along: Competition between species not main evolutionary driver

Horses have changed size and shape dramatically over the last 20 million years, evolving from small dog-sized creatures with multiple toes into the large, hoofed grazing animals we see today. But the factors that drove these changes have been unclear. In a new study in Science, scientists tested the long-held theory that horses evolved rapidly to compete with one another during the worldwide expansion of grasslands starting 18 million years ago.

07 Jun 2017

Horned dinosaur find a first for eastern North America

Fossils of horned dinosaurs called ceratopsids, the group that includes Triceratops, are usually found in either western North America or Asia. But the discovery of a single ceratopsid tooth in Mississippi, reported in a new study in PeerJ, hints that this group spread into new territory at the tail end of the Mesozoic Era — just prior to going extinct.

23 May 2017

First trilobite eggs found in fool's gold

Trilobites were one of the most successful groups of animals to ever scurry across the seafloor, thriving for more than 270 million years. But how they reproduced has long been a mystery, since no fossil had ever been found with preserved eggs or genitalia. With the discovery of a cluster of trilobite eggs preserved in pyrite in upstate New York, however, scientists are getting the first glimpse of how these early arthropods reproduced.

01 May 2017

Down to Earth With: Paleontologist Gerta Keller

The mass extinction that did in the dinosaurs is one of the best-known events in geology. It’s also one of the most contentious.

27 Apr 2017

Mastodon bones point to significantly earlier human presence in North America

In 1992, paleontologists from the San Diego Natural History Museum discovered a set of fossil bones, tusks and teeth from a single mastodon next to state highway 54 south of San Diego. Archaeologists were soon called to investigate the site, which also featured several large cobblestones — unique in the otherwise sandy matrix surrounding the bones — that seemed to have been used to break open the mastodon’s long bones, hinting at human activity soon after the animal’s death. A reliable age for the intriguing find has eluded scientists for more than two decades, but in a study released today in Nature, researchers who successfully dated the bones have come to a sensational conclusion: The site appears to date back roughly 130,000 years, more than 100,000 years before humans are thought to have lived in North America.

26 Apr 2017

Tiny dinosaur-era marsupial packed a big bite

Newly described fossils from one of the earliest-known marsupials are shedding light on the evolution of mammals during the Mesozoic and revealing an animal with an impressive bite, perhaps strong enough to take down a dinosaur.

19 Apr 2017

Scientists crack the secret of dinosaurs' incubation time

Paleontologists have long thought that the eggs of dinosaurs — like those of their living bird relatives — probably hatched after short incubation times, up to a few weeks at most. But surprising results from a new study suggest that nonavian dinosaurs spent anywhere from three to six months inside an egg, incubation times similar to reptiles like crocodiles and alligators.

18 Apr 2017

Lucy liked hanging out in trees

Lucy, the 3.2-million-year-old human ancestor discovered in Ethiopia in 1974, is one of the most complete early hominin skeletons ever found. Still, despite the skeleton’s completeness, debate continues about how Lucy got around: Did she spend most of her time walking on the ground or climbing in trees? In a new study, scientists studying Lucy’s upper limb bones have found that she likely spent more time in trees — and was a more capable climber — than later hominin species like Homo erectus and Homo sapiens.

13 Apr 2017

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