PALEO

paleo

Precambrian rumblings of the Cambrian Explosion

The Cambrian Explosion, when the ancestors of most of today’s animal groups began appearing in the fossil record about 542 million years ago, was — as the name suggests — a geologically abrupt event. Paleontologists have long thought of the event as marking a boundary between distinct Precambrian and Cambrian faunas. In new research published in Geology, however, scientists report that small, shelly fossils once thought to occur only in Cambrian rocks have been found in rocks dating to the late Ediacaran, just before the Cambrian, implying an earlier start to the explosion than previously thought.

11 Jul 2017

Bipedalism left its mark on human skull: Kangaroos and upright rodents show same signs

The transition to bipedal walking in our ancestors changed the hominin skeleton in many ways. New research looking at how upright walking affected the structures at the base of the skull in both early humans and other bipedal mammals, like kangaroos, is shedding light on a once-controversial marker for bipedalism.

04 Jul 2017

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

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