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Re: Bird reduce their "heating bills" in cold climates



Hello List,

just about 6 weeks ago I had the luck to see those things at the STMN (Shandong Tianyu Museum of Natural History, Pingyi). According to a complete specimen I saw in the collection there, only a small part of the integument is preserved in the holotype. They hold so many wonders in their museum, and the time was so short... Anyway, from what I recall (these things await description, so no pictures) the integument covers almost the whole animal in the complete specimen, except for some parts of the skull, and the feet. It looks very much like "basal feathering" that can be seen on many theropods (unbranched, propably hollow, "hair-like" structure). I for one would be _very_ much surprised if it turned out that those structures were actually not related to the animal - that they're anything but integument appears to be very, very unlikely to me.

Here are two highres photos I took of the holotype which is part of the permanent exhibiton of the STMN:
http://dubdivision.epourania.com/pics/Tianyulong_1.JPG
http://dubdivision.epourania.com/pics/Tianyulong_2.JPG

I wouldnt be surprised at all if one day it would become possible to demonstrate that the vast majority, if not all, of Dinosauria had some sort of "feathery" integument.

Greets!
Torsten

----- Original Message ----- From: "Jura" <pristichampsus@yahoo.com>
To: "DML" <dinosaur@usc.edu>
Sent: Monday, July 05, 2010 9:11 PM
Subject: Re: Bird reduce their "heating bills" in cold climates


--- On Mon, 7/5/10, David Marjanovic <david.marjanovic@gmx.at> wrote:

From: David Marjanovic <david.marjanovic@gmx.at>
Subject: Re: Bird reduce their "heating bills" in cold climates
To: "DML" <dinosaur@usc.edu>
Date: Monday, July 5, 2010, 2:07 PM
> Fuzzy integument is still
contentious for ornithischians (and
> unlikely IMO).

Doesn't *Tianyulong* show that it can happen?


++++++++++++++++++++++++++++++++++++++++++++

IF, what is preserved with _Tianyulong_ is actually related to the specimen at all, and not some unrelated object (e.g. plant material, bacterial film, parasite). That is something only further testing of the fossil will show.

______________________________________

> Even if it turns out to be true for a few
species, it seems more
> likely that it was an independent development
rather than an inherent
> character (i.e. not feathers).

Given pterosaurs, saurischians, and *Psittacosaurus*, it
might well be a symplesiomorphy. (*Psittacosaurus* shows
that "quills" don't need to cover the entire body, so I'm
not saying the first ornithodiran was fuzzy all over!)

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

You are oversimplifying here. "Saurischians" is really "maniraptors and a couple of non-maniraptoran coelurosaurs. The majority of known saurischian integument is scaly.

The "quills" in _Psittacosaurus_ may just be modified scales (their presence adjacent to real scales would favour this position), or they might be unrelated to fossil as well (they, too, have been questioned as being possible plant material).

Assuming that all these fossils are preserving real integument, it is still more parsimonious to assume that filamentous integument evolved on four separate occasions (coelurosaurs close to Maniraptora, Hypsilophodontids, _Psittacosaurus_, Pterosaurs), rather than the 7+ re-evolutions of a scaly covering that would be required if it was a symplesiomorphy.

_____________________________________________________



> As for
sue.
[...]

OK.

> Another possibility is that Leaellynasaura might
have been arboreal,
> and the tail may have been used in a
semi-prehensile fashion as seen
> in modern day green iguanas.

The anatomy of the tail and the rest of the body make that
very unlikely, AFAIK.

++++++++++++++++++++++++++++++++++++++++++++++++++

Hardly anything about the skeleton of green iguanas, screams arboreal either.

As for the tail, it seems to lack the ossified tendons of other iguanodontians, though even if it did, the degree of "stiffness" conferred by the ossified tendons, is not as much as was once thought (see Organ 2006).

Then there is the apparently flexed tail of a dromaeosaur that was on Tet Zoo.

http://scienceblogs.com/tetrapodzoology/2008/08/dromaeosaur_tails.php

Assuming that it wasn't a preservational artifact, then that is already about the same degree of flexibility seen in green iguana tails.

Jason