Re: Epidexipteryx

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

> This comes from the same fossil beds as Pedopenna ("feather foot") and 
> Epidendrosaurus,

Yes...

> which are now radiometrically dated at 152-168 million years.

No, no, no.

Wang Xiaolin, Zhou Zhonghe, He Huaiyu, Jin Fan, Wang Yuanqing, Zhang 
Jiangyong, Wang Yuan, Xu Xing & Zhang Fucheng: Stratigraphy and age of the 
Daohugou Bed in Ningcheng, Inner Mongolia, Chinese Science Bulletin (English 
edition) 50(20), 2369 -- 2376 (October 2005)

The Tiaojishan Fm, which has the mentioned radiometric date ( = Middle-Late 
Jurassic boundary), underlies the Daohugou Bed, rather than overlying it.

> The geology is pretty complex,

Quite so. That's why it was even possible to confuse up and down.

> and I think the dates are still controversial,

They shouldn't be.

> but this definitely is an older fauna than the Jehol,

Yes, but nobody knows by how much, except that the Middle-Late Jurassic 
boundary is the upper limit. The Daohugou Bed could be just older than the 
Yixian Fm. (Its relationships to the Hauterivian Dabeigou Fm and the 
Berriasian Tuchengzi Fm are unknown.)

> 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).

On a relative scale, however, Archie is dated quite securely at Tithonian.

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

Which, in turn, was no more arboreal than a pigeon... 
*Epidendrosaurus/Scansoriopteryx*, however, does have two or three arboreal 
adaptations.

> Anyway, it's a wonderful fossil, and I am looking forward to seeing more.

Start here: 
http://scienceblogs.com/tetrapodzoology/2008/10/epidexipteryx_at_last.php