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RE: Article on Archaeoraptor hoax and Dinosaur/Tech Geek Toy
Tom Holtz wrote:
> _Yanornis martini_ has priority over "Achaeovolans", since the former
> was named last year.
I think _Archaeovolans_ is a valid name - though the description was
definitely wanting (don't get me started...). Time will tell if it's a
valid genus (i.e. if it's a subjective junior synonym of _Yanornis_ or
another previously-described taxon). I hate the name as much as I hated the
description. Oops, now I've done it...
Also in _Nature_:
Evolution: "Flat out for feathers"
Discoveries of fossil dinosaurs bearing feather-like structures have
prompted increased interest in the origin and evolution of feathers. A study
of how regenerating flight feathers of chickens respond to various genes
delivered by a viral vector reveals that the balance between two proteins,
noggin and bone morphogenetic protein 4, is critical in feather branching.
Another protein, sonic hedgehog, is essential for inducing the cell death
that results in spaces between barbs. The data suggest that a radially
symmetric feather is more primitive than the 'flat' feather, and may have
been the prototype of feathers.
"The morphogenesis of feathers"
M. YU, P. WU, R. B. WIDELITZ & C.-M. CHUONG
_Nature_ 420: 308-312.
Feathers are highly ordered, hierarchical branched structures1, 2 that
confer birds with the ability of flight3-5. Discoveries of fossilized
dinosaurs in China bearing 'feather-like' structures have prompted interest
in the origin and evolution of feathers6-14. However, there is uncertainty
about whether the irregularly branched integumentary fibres on dinosaurs
such as Sinornithosaurus are truly feathers11, and whether an integumentary
appendage with a major central shaft and notched edges is a non-avian
feather or a proto-feather8-10. Here, we use a developmental approach to
analyse molecular mechanisms in feather-branching morphogenesis. We have
used the replication-competent avian sarcoma retrovirus15 to deliver
exogenous genes to regenerating flight feather follicles of chickens. We
show that the antagonistic balance between noggin and bone morphogenetic
protein 4 (BMP4) has a critical role in feather branching, with BMP4
promoting rachis formation and barb fusion, and noggin enhancing rachis and
barb branching. Furthermore, we show that sonic hedgehog (Shh) is essential
for inducing apoptosis of the marginal plate epithelia, which results in
spaces between barbs. Our analyses identify the molecular pathways
underlying the topological transformation of feathers from cylindrical
epithelia to the hierarchical branched structures, and provide insights on
the possible developmental mechanisms in the evolution of feather forms.
There's also an unsettling story about a stolen allosaur fossil...
"Dinosaur curators plot mating game" DALTON, R.
_Nature_ 420: 259
The first bit of the story:
[SAN DIEGO] Friends of 'Big Al', Montana's most famous dinosaur, want a
buddy of the allosaurus to come home to the United States. Big Al is
displayed at the Museum of the Rockies in Bozeman. His buddy, a
near-complete skeleton of another allosaurus, was stolen a decade ago from
federal land in Utah and sold to a private museum in Japan. Now Mark
Goodwin - a palaeontologist at the University of California, Berkeley, who
has helped to repatriate pilfered specimens in the past - has started a
drive for the return of the rare dinosaur.