This is an offshoot of the thread, "A new shark-toothed theropod from Uzbekistan," where the topic shifted to bird origins.
On Thursday, September 16, 2021 at 11:54:14 PM UTC-4, Oxyaena wrote:
On 9/16/2021 9:08 PM, Peter Nyikos wrote:
[snip]
This snip followed a talk.origins "custom" of leaving in a bit of context
but snipping the attribution line of who had provided the context.
Here is the line, restored:
On Thursday, September 16, 2021 at 3:05:06 PM UTC-4, John Harshman wrote:
What is clear, however, is that the protofeathers of
maniraptorans are protofeathers.
Why? because a good number of maniraptorans have what you optimistically call "protofeathers"
and a good number (including *Caudipteryx*) have true feathers?
Why are you so disparaging of the term "protofeathers"?
As the word "optimistically" should have tipped you off, I am not
disparaging of the expression, but only of uses that aren't
accompanied by the tiniest smidgin of evidence. Which is what
Harshman's idiocy amounts to.
<snip of a different idiocy by you, to be dealt with on the original thread>
But why would you expect a given
fossil to have both, if one evolved from the other?
Why do you think ANYONE would entertain such an expectation? I certainly never
hinted at having one. Quite the contrary.
Then what is your expectation?
You are flagrantly evading the question. But I'll humor you by cutting the Gordian
knot now.
We are both agreed that true feathers -- calamus, shaft, barbs, barbules and hooks --
are too complicated to have arisen independently on more than one lineage. So my expectation is that they are all in one clade, perhaps only within Maniraptora.
And that hairlike "protofeathers" are widely distributed through Dinosauria,
and perhaps through Archosauria.
Given that pterosaurs also exhibit what you like to call "dinofuzz,"
that's a reasonable expectation.
Yes, I've commented on that before, over the years, and it was
pterosaurs that I had in mind when I wrote the above. But I only call it "dinofuzz" when it shows up in fossils of dinosaurs.
But did you ever see ANY examples outside Coelurosauria
(or, for that matter, outside Maniraptora) of any stages in the
direction of true feathers? Partisans of the word "protofeathers,"
such as Prum and Brush [appropriate surname!] have hypothesized
at least two stages between them and true contour feathers, with
flight remiges a step beyond them.
In fact there's evidence that
crocodiles have LOST this "dinofuzz," due to some quirk of genetics.
I've seen the title of a research article that hinted at genetic apparatus
for such hairlike skin covering going that far back, but was looking for something else at the time and so I didn't record it.
I used to know the exact series of mutations in question, but it's been
some years since I last read on the topic.
Can you still find a reference to it? I'd be very interested.
Remainder deleted, to be dealt with on the original thread.
Peter Nyikos
Professor, Dept. of Mathematics -- standard disclaimer--
University of South Carolina
http://people.math.sc.edu/nyikos
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