An alvarezsaurid from the beginning of the Late Jurassic

[David Marjanovic <david.marjanovic@gmx.at>]

As I just mentioned...

Jonah Choiniere, James Clark, Xu Xing & Han Fenglu (2009): A new basal 
alvarezsaur from the Shishugou Formation, online-only supplement to JVP 
29(3), 77A & 78A

>>
The Alvarezsauridae are a Cretaceous clade of theropod dinosaurs with 
highly modified
forelimbs. The phylogenetic position of the Alvarezsauridae has been 
uncertain, with inital
systematic research positing them as basal avialians, other analyses 
finding a sister-group
relationship between Ornithomimosauria and Alvarezsauridae, and some 
recent analyses
placing the family at the base of Maniraptora. The latter phylogenetic 
hypothesis implies
that a ghost lineage of over 60 million years exists between the 
Alvarezsauridae and the
oldest-known maniraptorans (Scansoriopterygidae). We report here on a 
complete specimen
of a new basal alvarezsaur from the Shishugou Formation in Xinjiang, 
China. Extensive
radiometric dating of Shishugou volcanic tuffs constrains the age of the 
specimen to between
158.7 +/- 0.3 mya and 161.2 +/- 0.2 mya, approximately at the beginning 
of the Late
Jurassic. This new taxon extends the stratigraphic range of the 
Alvarezsauridae by 60 million
years, provides new information about alvarezsaur morphological 
evolution, confirms a
basal position for the Alvarezsauridae within the Maniraptora rather 
than within Avialae or
sister to Ornithomimosauria, and indicates that the earliest members of 
the family were not
Gondwanan, as previous studies have suggested.
<<

Another paper to wait for. :-)

I think I can say that the poster showed a fairly complete and very 
well-preserved skeleton.