Unshelled ancestor fills big gap in turtle family tree

Turtles may seem like innocent creatures, but the uniquely shelled reptiles have long posed a problem for paleontologists. Shelled turtles are plentiful in the fossil record, but specimens of their intermediate forebears — the missing links between ancestral unshelled reptiles and modern turtles — have remained elusive. Now, a closer look at the skull of what may be one of the earliest turtle relatives is filling gaps in the turtle family tree.
28 Dec 2015

Oldest marine turtle found in Colombia

A 120-million-year-old sea turtle recently discovered in Colombia is about 25 million years older than the previously oldest-known marine turtle. Despite its age, the new 2-meter-long specimen is very similar to living marine turtles and was placed in the group Chelonioidea, which includes the modern Hawksbill turtle and green sea turtle.
28 Dec 2015

The Snowmastodon Project: Mammoths and mastodons lived the high life in Colorado

In fall 2011, a bulldozer driver in Snowmass, Colo., unearthed an unprecedented trove of Pleistocene-aged fossils. Over the next few months, “Snowmastodon” became one of the largest fossil excavations ever. Scientists have already learned a lot from the bones.

13 Dec 2015

What happened here?

Why did so many animals end up buried at the Snowmastodon site? What happened to them? “We really struggled to figure out why there were so many bones found in this location,” says Ian Miller, chair of earth sciences and the paleobotanist at the Denver Museum of Nature & Science who co-led the Snowmastodon Project. “Was it some kind of deathtrap? Or was there a deadly catastrophe like an earthquake or a landslide?” 
13 Dec 2015

Volunteering to muck around in the mud

The Snowmastodon Project team pulled thousands of fossils out of snowy mud in a matter of months, a herculean task that would not have been as successful without a small army of volunteers, many of whom came from the Denver Museum of Nature & Science’s paleontology program. The program trains interested laypeople in the art of collecting, studying and curating fossils, one of the only programs like it in the world. 
13 Dec 2015

Moroccan fossil formation reshapes timeline of Early Phanerozoic evolution

Many new life-forms emerged during both the Cambrian Explosion and the Great Ordovician Biodiversification Event, but a lack of fossils from the 40-million-year span in between has left scientists wondering if a period of evolutionary stasis took hold between the two booms. Now, the discovery of a prodigious bed of fossils in Morocco that date to between 485 million and 444 million years ago indicates that the Ordovician boom may actually have been a continuation of the Cambrian Explosion, with little to no evolutionary downtime in between.
02 Dec 2015

Warty algae-like sheets survived Snowball Earth events

Between about 730 million and 635 million years ago, during the Cryogenian Period of the Late Proterozoic, Earth is thought to have been almost completely covered in ice twice, events that scientists have termed “Snowball Earth” glaciations. The first global glaciation, the Sturtian, lasted from 730 million to 700 million years ago, and the second, the Marinoan, lasted from 660 million to 635 million years ago. Both glaciations likely put severe limitations on the ability of life — predominately microorganisms — to thrive. 
19 Nov 2015

Owl pellets bridge ancient and modern ecosystems

In Homestead Cave near Utah’s Great Salt Lake, owls have been regurgitating pellets containing the undigested bones and hair of prey — typically small mammals like rodents — at a relatively constant rate since the end of the Pleistocene glaciations about 13,000 years ago. Those pellets have stacked up and fossilized in the cave to present a near-continuous glimpse into how mammal communities in this part of the Great Basin region have changed over time. Now, paleontologists examining bones in the pellets have found that, although small mammals in the region have generally been able to adapt to shifting ecosystems in the past, today, in the face of landscape-altering human activity, the mammal population is changing in unprecedented ways.
25 Oct 2015

Triceratops relative 'Wendi' sported a fantastic frill

The discovery of a 79-million-year-old frilled and horned relative of Triceratops is shedding light on the early evolution of the ceratopsid’s distinctive look. The new specimen, discovered in a quarry in southern Alberta, Canada, and described recently in PLOS ONE, was named Wendiceratops pinhornensis after the famed fossil hunter Wendy Sloboda of the University of Lethbridge in Alberta, who discovered the site in 2010.
24 Oct 2015

A Cambrian-like explosion of mammals in the Mid-Jurassic

Dinosaurs dominated the continents during the Mesozoic, and for a long time, paleontologists assumed our mammalian ancestors kept a low-profile in that era, existing only as small, ground-dwelling, nocturnal insect-eaters. But in the last decade, discoveries of an ever-increasing diversity of mammal fossils have forced a rethink: Mesozoic mammals were also gliders, climbers, diggers and swimmers. Now, scientists looking at mammalian rates of evolution during the time of the dinosaurs have found that this diversity peaked in the Mid-Jurassic, leading to new physical characteristics that would remain for millions of years.
20 Oct 2015