* Astronomy

Volcanic eruptions preserve ancient history
Case assistant professor harvests the fossilised bones of animals from South America
A catastrophic mudflow some 25 to 28 million years ago stopped a nine-inch armadillo in its tracks. Frozen in time, the small animal would not come to light again until this past March when Darin Croft from the Case Western Reserve University School of Medicinea member of an international field team including U.S. and Chilean researcherspicked up the fossil embedded in the dark purple rock that was once volcanic mud.
The yet undescribed specimen was found in a remote central Chilean field site in the Río Maipo valley. The small animal resembles a modern-day armadillo with its hinged plates that form a hard armoured shell. It is small by today's standards, but its fused limb bones indicate the animal had reached adulthood.

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An international team of American and Chinese palaeontologists has discovered a new species of mammal that lived 125 million years ago during the Mesozoic Era, in what is now the Hebei Province in China.
The new mammal, documented in the March 15 issue of the journal Nature, provides first-hand evidence of early evolution of the mammalian middle ear--one of the most important features for all modern mammals. The discovery was funded by the National Science Foundation (NSF).

"This early mammalian ear from China is a rosetta-stone type of discovery which reinforces the idea that development of complex body parts can be explained by evolution, using exquisitely preserved fossils" - H. Richard Lane, program director in NSF's Division of Earth Sciences, which co-funded the discovery with NSF's Division of Environmental Biology and its Assembling the Tree of Life (AToL) program.

Named Yanoconodon allini after the Yan Mountains in Hebei, the fossil was unearthed in the fossil-rich beds of the Yixian Formation and is the first Mesozoic mammal recovered from Hebei. The fossil site is about 300 kilometres outside of Beijing.
The researchers discovered that the skull of Yanoconodon revealed a middle ear structure that is an intermediate step between those of modern mammals and those of near relatives of mammals, also known as mammaliaforms.

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Title: Miocene mammal reveals a Mesozoic ghost lineage on insular New Zealand, southwest Pacific
Authors: Trevor H. Worthy, Alan J. D. Tennyson, Michael Archer, Anne M. Musser, Suzanne J. Hand, Craig Jones, Barry J. Douglas, James A. McNamara, and Robin M. D. Beck

New Zealand (NZ) has long been upheld as the archetypical example of a land where the biota evolved without nonvolant terrestrial mammals. Their absence before human arrival is mysterious, because NZ was still attached to East Antarctica in the Early Cretaceous when a variety of terrestrial mammals occupied the adjacent Australian portion of Gondwana. Here we report discovery of a nonvolant mammal from Miocene (19-16 Ma) sediments of the Manuherikia Group near St Bathans (SB) in Central Otago, South Island, NZ. A partial relatively plesiomorphic femur and two autapomorphically specialized partial mandibles represent at least one mouse-sized mammal of unknown relationships. The material implies the existence of one or more ghost lineages, at least one of which (based on the relatively plesiomorphic partial femur) spanned the Middle Miocene to at least the Early Cretaceous, probably before the time of divergence of marsupials and placentals >125 Ma. Its presence in NZ in the Middle Miocene and apparent absence from Australia and other adjacent landmasses at this time appear to reflect a Gondwanan vicariant event and imply persistence of emergent land during the Oligocene marine transgression of NZ. Nonvolant terrestrial mammals disappeared from NZ some time since the Middle Miocene, possibly because of late Neogene climatic cooling.

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The creature, which has been named Horolodectes sunae because of the unusual shape of the crowns of the teeth, lived about 60 million years ago, soon after the dinosaurs went extinct.

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