Epidexipteryx

[Jeff Hecht <jeff.hecht@sff.net>]

My New Scientist story is on-line this morning at 
http://www.newscientist.com/article/dn15017-halffeathered-dinosaur-was-a-bit-of-a-showoff.html?DCMP=ILC-hmts&nsref=news1_head_dn15017

Epidexipteryx  is a fascinating critter. I've corresponded with the authors, 
and wasn't able to get all the details into my story, so I'll add a few bits 
here.

This comes from the same fossil beds as Pedopenna ("feather foot") and 
Epidendrosaurus, which are now radiometrically dated at 152-168 million years. 
The geology is pretty complex, and I think the dates are still controversial, 
but this definitely is an older fauna than the Jehol, and if the dating is 
right probably is older than Archaeopteryx (with the caveat that Archaeopteryx 
itself is not firmly dated on a radiometric scale).

So what we're seeing are little feathered dinosaurs, but nothing yet with 
flight feathers or true wings, in the sense they could be used for flight or 
even gliding. Obviously finding more fossils is very very important, and I'm 
sure IVPP is working on that. Judging from what has come out so far, the 
Daohugou either is not as fossil-rich as the Jehol deposits or they haven't 
found the mother lode of fossils.

Zhang et al say the tail is complete and its vertebrae differ from those of 
Epidendrosaurus, supporting the idea the two are different. It would obviously 
be very nice to have more fossils to get growth sequences of the two. There are 
very faint feather impressions on Epidendrosaurus, and downy feather 
impressions from the whole body of Epidexipteryx, not just on the shoulders 
where they are clearest in the photos.  Thus the downy covering on the 
reconstructions.

THey also say its claws show it could climb, probably about as well as 
Microraptor.

All of which leaves us with a diverse range of little feathered dinosaurs 
closely related to birds running around the late Jurassic and early Cretaceous. 
The tail display feathers show internal structures somewhat similar to - but 
significantly different from - flight feathers. So it looks like evolution was 
experimenting with different forms of the things that eventually became what we 
recognize as feathers. Maybe Alan Brush can weigh in with his observations when 
he has a chance to study the paper more carefully.

Anyway, it's a wonderful fossil, and I am looking forward to seeing more.
-- 
Jeff Hecht,    science and technology writer
Boston Correspondent, New Scientist magazine
525 Auburn St.,   Auburndale, MA 02466   USA
V 617-965-3834    e-mail jeff@jeffhecht.com
Web  http://www.jeffhecht.com