Feathered dinosaur predates oldest bird
Paleontologists have unearthed a long-sought treasure — evidence of a feathered dinosaur older than Archaeopteryx, the 150-million-year-old creature often considered to be the first known bird (SN: 10/24/09, p. 8). The newly described species, the peacock-sized Anchiornis huxleyi, lived in what is now northeastern China between 151 million and 161 million years ago and sported two types of feathers. One kind, which resemble the feathers of modern-day birds, adorned the creature’s feet and lower legs as well as its forelimbs — an arrangement that may have made the creature clumsy on the ground and bolsters the notion that flight originated from the trees down, some paleontologists say. Another team reported finding different fossils that were partially covered with stiff, unbranched filaments (SN Online: 1/12/09). Paleontologists had previously theorized that structures like these could be part of the path leading to today’s flight-capable feathers.
Sea-level rise and subsiding lands in the Mississippi Delta will claim 10 percent of the state by 2100, a report finds (SN: 7/18/09, p. 15).
Bird in the hand
Fossilized fingers strengthen the evolutionary link between dinosaurs and avian relatives (SN: 7/18/09, p. 12), and fossil handprints made by a crouching theropod reveal birdlike arm anatomy (SN: 3/28/09, p. 9).
Paleontologists rummaging through museum drawers discover the remains of North America’s smallest carnivorous dinosaur — a theropod the size of a chicken (SN Online: 3/16/09).
Big gulp, Asian style
Satellite data reveal that increased irrigation is rapidly depleting groundwater in northern India (below, greatest depletion in pink) and surrounding regions (SN: 9/12/09, p. 5).
Nickel down, oxygen up
A decrease in the amount of dissolved nickel in ocean waters beginning 2.7 billion years ago could have stifled methane-producing bacteria and set the scene for oxygenation of the Earth’s atmosphere, researchers suggest (SN: 5/9/09, p. 14).
A tiny zircon in a rock brought back from the moon in 1972 is hinting that the satellite’s surface solidified by 4.4 billion years ago (SN Online: 1/26/09).
Small preserved primate
A 95-percent-complete skeleton of a small, 47-million-year-old primate is found in volcanic ash in Germany (SN: 6/20/09, p. 8).
Overall, the world’s vegetation absorbed carbon dioxide more efficiently in the diffuse sunlight filtering through the polluted skies of recent decades than it would have with a pristine atmosphere, a new analysis reveals (SN: 5/23/09, p. 14).
Organisms living on Earth during a period of asteroid bombardment about 3.9 billion years ago could have survived the pummeling by inhabiting ecosystems around hydrothermal vents created by the impacts, scientists say (SN Online: 5/20/09).
Contrary to the findings of previous studies, much of Antarctica has warmed in recent decades — and it has done so at rates similar to the global average (SN: 2/14/09, p. 8).
Tiny crystals in Australian rocks hint that photosynthesizing life existed earlier than had been thought (SN: 4/11/09, p. 9).
Auroras in the Northern Hemisphere are not always a mirror image of those over Antarctica (SN: 8/15/09, p. 14).
Boring billion years
Even after oxygen-producing cyanobacteria evolved, sulfur-loving microbes may have stalled the evolution of complex life by keeping oxygen levels low and waters toxic (SN Online: 9/29/09).
Farming stifled monsoon
The expansion of agriculture and the resulting deforestation in India and southeastern China during the 18th century triggered a drop in precipitation, a study suggests (SN Online: 6/1/09).
Monitoring slow quakes in subduction zones could offer a way to understand how stress is distributed among portions of a fault (SN: 8/29/09, p. 26).