Taxonomy term

mary caperton morton

A terribly low voice for a new terror bird

A recently discovered fossil skeleton is giving paleontologists a nearly complete look at a new species in the family of big-beaked giants known as “terror birds.” Thought to have grown as tall as 3 meters, these flightless birds roamed South America as apex predators before going extinct about 2.5 million years ago.
 
12 Aug 2015

Southbound icebergs off the hook for ice-age cooling

During the Late Pleistocene, changes in North Atlantic Ocean circulation triggered abrupt changes in global climate: In some locations in the Northern Hemisphere, average temperatures dropped by as much as 10 degrees Celsius within a few decades. Scientists have long thought that freshwater from melting icebergs traveling south from the Arctic may have instigated the circulation shifts that contributed to cooling feedback loops. But now, scientists looking at seafloor sediments collected near Iceland have found that pulses of icebergs typically arrived after the onset of cooling episodes, too late to be primary drivers of climate change.
 
11 Aug 2015

From fearsome predator to filter feeder

Early in the Paleozoic, giant arthropods known as anomalocaridids were the largest predators in the sea. A collection of finely preserved fossils, described in a new study in Nature and belonging to the Early Ordovician Fezouata Biota of Morocco, is now giving paleontologists a more detailed look at a 2-meter-long variety called Aegirocassis benmoulae. The fossils seem to suggest that at least this species wasn’t a predator after all.
 
10 Aug 2015

Stalled slabs sometimes stopped by mineral strengthening

Subduction of tectonic plates into the mantle functions as an eons-long recycling system for Earth’s crust and lithosphere. But in some subduction zones, the downgoing slabs seem to get stuck at depths of about 1,000 kilometers, held up by some unseen barrier on their journey deeper into the lower mantle. Now, scientists propose that this barrier might be related to high-pressure-induced strengthening of minerals in the rocks surrounding subducting slabs at these depths.
09 Aug 2015

Bark beetles not to blame for big fires?

Since the mid-1990s, outbreaks of voracious bark beetles have devastated more than 71,000 square kilometers of forests in the Rocky Mountain West. Contrary to popular belief, however, the huge swaths of standing dead trees left behind don’t necessarily pose an increased fire hazard, according to a new study. The finding calls into question the efficacy of recently enacted policies entailing the thinning of beetle-killed forests.
 
08 Aug 2015

Nonnative plants not a problem in Britain

In many places in the world, nonnative plants are epidemic, outcompeting local flora for space and resources and sometimes leading to extinctions of native plants. But a new study finds that, in Britain at least, foreign plants don’t seem to be negatively impacting the natives after all.
 
07 Aug 2015

Makeovers for two popular dinosaurs

Two of the most recognizable dinosaurs are getting image makeovers. According to recent research, tyrannosaurs weren’t only fearsome predators with a taste for other species, but also may have been cannibals; and Brontosaurus, long thought to be obsolete — as a distinct genus at least — may be making a comeback.
 
06 Aug 2015

A pair of moons with underground oceans

Jupiter and Saturn are both gas giants boasting multiple moons. Now, two separate studies have identified another similarity: Each appears to have a moon with hidden underground oceans.
 
02 Aug 2015

Widening the window of human dispersal into Arabia

The vast sea of sand that is much of the Arabian Peninsula presents a formidable barrier to travel, even with today’s modern conveniences. How and when our ancestors crossed this dry expanse after leaving Africa — on their way to populating the rest of the world — has long been a mystery. Now, a new paleoclimate study paints a wetter picture of Arabia during the time of human expansion, and the findings may change scientists’ thinking about the route and timing of early human migrations out of Africa.

31 Jul 2015

Great drying led to great dying down under

If not for the megafaunal extinctions that wiped out many large animals at the end of the Pleistocene, the world might be a very different place today — with humans coexisting alongside still-living saber-toothed tigers, woolly mammoths and 3-meter-tall birds. The agents of these mass extinctions have been debated for decades: Were shifting climates, or our spear-wielding ancestors mainly responsible? A new study of the receding shorelines of Australia’s largest lake has found that a substantial drying of the environment, more so than human pressure, is mostly to blame for the loss of megafauna down under.
 
08 Jul 2015

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