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Re: MORE FEATHERS & NEKKID MAMMALS
Jeffrey Martz wrote (quoting me):
> > All birds are reptiles and all bird young that I know of have feathers. If
> Birds are born smooth skinned in the areas that will later
> produce feathers. We are not just talking about dropping off the
> feathers as the animal gets older, but fundamentally changing the nature
> and texture of the skin. All modern animals with scales HAD THEM THERE
> FOR THE ENTIE DURATION OF THIER LIFE. This includes, if I'm not
> mistaken, the scales on birds LEGS.
I am almost 100% certain that some if not most birds are born with feathers.
I know that some are born naked skinned on some parts of their bodies
> > you are talking about reptiles in the colloquial "all amniotes that aren't
> > mammals or birds" sense, then you're right; but they do not possess them
> > because they don't have the potential to.
> What makes you think dinosaurs Tyrannosaurs had the potential to?
> T.rex didn't have a lot of other avian/_Archaeopteryx_
> osteological characteristics, so why are you assuming that feathers were
> were among the SOFT ANATOMY traits shared with birds?
> Why do you keep saying that T.rex young were "probably" feathered?
> Infant feathers were offered as a purely speculative possible solution to
> temperature control problems for young dinosaurs.
Because, as we understand dinosaur systematics at this moment in time
TYRANNOSAURS ARE CLOSER TO BIRDS THAN ARE COMPSOGNATHIDS. Period.
Tyrannosaurs fall with in the clade Coelurosauria (Compsognathus + Corvis),
and so, therefore had the potential to be feathered.
> > Again, you are using the colloquial reptile. Birds are reptiles whose
> > young
> > are insulated.
> But not all reptiles are insulated. At some point, the transition
> was made from a scaled, non-feathered animal to a feathered one WITHIN
> the Reptilia.
The fossil record suggests that Avimimus didn't have a tail because no one
has found one yet; but I'll bet $100,000 it had one. Just because there arer
skin impressions for roughly five groups of large dinosaurs (Carnotaurids,
Tyrannosaurids, some sort of Sauropods, Ceratopids and Hadrosaurs) that have
scaly skin, and NO skin impressions of their young doesn't mean that they
weren't insulated. Because we have skin impressions of two animals that are
definately not birds, but seem to possess feathers (Sinosauropteryx,
Pelecanimimus), and because one of the big scaly dinosaurs falls within this
clade, it is logical to assume that the young of the big scaly dinosaur were
feathered. This can be used with other big scaly dinosaurs and their young
because one would assume that they were physiologically more similar to
eachother than to something like a crocodile.
> If the bird feathers and pterosaur hairs are really homologous, I
> admit that would be a problem. It sure would be nice if we could run
> protein analysis of hairs in a living pterosaur...
Yes, any living dead thing would be nice....