Juramaia, Jurassic eutherian from China

[bh480@scn.org]

bh480@scn.org

A Mesozoic mammal of interest:

Zhe-Xi Luo, Chong-Xi Yuan, Qing-Jin Meng & Qiang Ji (2011)
Jurassic eutherian mammal and divergence of marsupials 
and placentals.
Nature 476: 442?445 
doi:10.1038/nature10291 
http://www.nature.com/nature/journal/v476/n7361/full/natur
e10291.html


Placentals are the most abundant mammals that have 
diversified into every niche for vertebrates and 
dominated the world?s terrestrial biotas in the Cenozoic. 
A critical event in mammalian history is the divergence 
of eutherians, the clade inclusive of all living 
placentals, from the metatherian?marsupial clade. Here we 
report the discovery of a new eutherian of 160 Myr from 
the Jurassic of China, which extends the first appearance 
of the eutherian?placental clade by about 35 Myr from the 
previous record, reducing and resolving a discrepancy 
between the previous fossil record and the molecular 
estimate for the placental?marsupial divergence. This 
mammal has scansorial forelimb features, and provides the 
ancestral condition for dental and other anatomical 
features of eutherians.


News Stories:
http://www.carnegiemnh.org/press/11-jul-
sep/082511fossil.htm
http://www.eurekalert.org/pub_releases/2011-08/cmon-
doa081911.php
http://www.pittsburghlive.com/x/pittsburghtrib/news/pittsb
urgh/s_753170.html