AW: Heterodontosaurid with protofeathers

[evelyn sobielski <koreke77@yahoo.de>]

> http://scienceblogs.com/notrocketscience/2009/03/tianyulong_-_a_fuzzy_dinosaur_that_makes_the_origin_of_feath.php

So the critters that (presumably) left the "avian" footprints in Triassic rocks 
*did* have "feather-like" integument after all ;-)

But I don't find this all to spectacular. As the article says:

"Only one other ornithischian, an early horned dinosaur called Psittacosaurus, 
had similar structures but its filaments were sparser, more rigid and only 
found on its tail."

The Senckenberg museum has the cutest reconstruction of a _Psittacosaurus_ 
(http://img175.imageshack.us/img175/5657/psittacosaurus2copienw0.jpg) and if 
you have ever seen this model live, you won't be too amazed about _Tianyulong_.

If the phylogenetic position of birds and mammals in respect to dinosaurs were 
the other way of what it is, this discovery would be hailed not as "feathers" 
but as "fur". 

It was neither. 

We need to come to terms with the fact that there are not just 2 kinds of 
elongated keratinaceous integumentary structures. The pterosaur researchers 
have grasped this already, but it gets tiresome to see every wisp of dino 
"hair" be touted as if it were a veritable rectrix. 

Dinosaurs were not squamates, so there is no reason to assume their integument 
was any more like that of squamates than is that of crocodiles or turtles.

The really interesting question here - and it is one that is likely to be 
swamped by a deluge of faux-feather headlines - is: why? What is the use of 
such integumentary structures? It is hard to see them as evolutionary neutral, 
so they are likely to have conferred some benefit. What precisely did it evolve 
for?


Regards,

Eike