RE: Dinosaur Revolution Review (Baby Fuzz)

[Sim Koning <simkoning@msn.com>]

Scott Hartman Wrote:

 

"1) Have the juvenile fuzz grow out of pebbly-scaled skin, rather than
naked skin.  Or...
 
2) Have the adults have naked skin in those areas that were fuzzy as a
hatchling.  I don't know if it would be aesthetically pleasing, but
there's no reason a grown T. rex might not have a scale-covered tail,
feet, and snout and be otherwise naked-skinned."
 


Matt Martyniuk Wrote:

 

"This second option Scott lists is the closest analogue to the actual
fossil record, as far as I can tell. As Mickey states on The Theropod
Database:"
   
-------------------------
  

  I somehow missed the bit about Dr. Holtz's description of the Gorgosaurus 
skin. Based on his description, I would guess that it may have been somewhere 
between those two options. The adult may have retained some of its feathers 
with those sections of the skin sparsely scaled while feathers were in between. 
As they grew to adulthood, the scaled areas may have expanded as the surface 
area increased. I believe that is what Dr. Holtz suggested earlier in this 
thread.  
 


  Also, I think we should be careful when making arguments from analogy based 
on extant birds. Imagine if we were unaware of the Hoatzin. I suspect many 
would likely express incredulity at the notion that a species of bird could 
replace clawed hands with wings as it matured. I would not be surprised at all 
if we discovered for instance that hadrosaurid hatchlings were fuzzy. If this 
were the case, it leaves me to wonder why at least one species of sauropod was 
born scaled and not 'fuzzy'. Perhaps it was the reverse of what we see today 
with modern birds? We never see birds replacing feathers with scales, but as 
several others have explained, this may be a derived trait of Neornithes and 
atypical of the rest of Dinosauria. Perhaps the reverse happened at some point 
with Sauropod evolution. I have a few guesses as to why: many titanosaurs were 
covered in armor not unlike ankylosaurs and so they lack feathers in favor of 
armor. Or perhaps sauropods developed an alternate system of thermoregulation 
more effective for such massive animals. Crocodiles use highly vascular scutes 
while giraffes use vascular dark patches of skin; maybe sauropods did the same. 
So, I will remain comfortable with depictions of fuzzy dinosaur babies until we 
find non sauropod hatchlings with preserved integument. The advantages provided 
by insulation for a fast growing baby dinosaur would be great, and there is at 
least one example of an equally, if not more dramatic ontogenetic change in one 
extant species of dinosaur>    
http://geology.cwru.edu/~huwig/catalog/slides/695.I.12.jpg