Glenn
On Thu, 30 Apr 1998 20:33:58 -0500, Glenn Morton wrote:
GM>Concerning claims that Longisquama was ignored over the years and thus a
>young-earth creationist making the claim that there is no half-evolved
>feather should not be held accountable for knowing about it...
The actual claim was that:
"There are no true transitional forms (that is, in the sense of forms containing
incipient, developing or transitional structures-such as half-scales/half-feathers,
or half-legs/ half-wings) anywhere among all the billions of known fossil forms."
(Morris H.M. & Parker G.E., "What is Creation Science?," 1987, p11)
The emphais is on the "true". M&P would no doubt agree that there are
*claimed* transitional forms, but they believe that these are not "true transitional
forms":
"...the stratomorphic intermediate evidences are not without difficulty for
evolutionary theory. First, none of the stratomorphic intermediates have
intermediate structures. Although the entire organism is intermediate in
structure, it's the *combination* of structures that is intermediate, not the
nature of the structures themselves. Each of these organisms appears to
be a fully functional organism full of fully functional structures.
Archaeopteryx, for example, is thought to be intermediate between reptiles
and birds because it has bird structures (e.g, feathers) and reptile
structures (e.g., teeth, forelimb claws). Yet the teeth, the claws, the
feathers and all other known structures of Archaeopteryx appear to be fully
functional. The teeth seem fully functional as teeth, the claws as claws,
and the feathers as any flight feathers of modern birds. It is merely the
combination of structures that is intermediate, not the structures
themselves." (Wise K.P., "The Origin of Life's Major Groups," in Moreland
J.P., ed., "The Creation Hypothesis," 1994, p227)
This is a YEC claim. One proved major transitional form would be *fatal* to
YEC which holds that all the major "kinds" were created de novo within
6 x 24-hour days, about 10,000 years ago.
My Mediate Creation position is not that there are no transitional forms, but
there are not enough of them. What the fossil record pervasively reveals
is therefore not *Darwinian* evolution:
"Because Darwinian evolution is a purposeless, chance-driven process,
which would not proceed directly from a starting point to a destination,
there should also be thick bushes of side branches in each line. As Darwin
himself put it, if Darwinism is true the Precambrian world must have "swarmed
with living creatures" many of which were ancestral to the Cambrian animals."
(Johnson P.E., "Darwinism's Rules of Reasoning", in Buell J. & Hearn V., eds.,
"Darwinism: Science or Philosophy?", 1994, pp13-14)
But having said that, while not ruling out such "true transitional forms" *to date*
I have seen no good evidence that there are "forms containing incipient,
developing or transitional structures-such as half-scales/half-feathers, or half-
legs/ half-wings."
GM>In April 1975, Longisquama made the cover of Scientific American. Pretty
>good for a 225 million year old girl from Russia.
Which in itself defeats his own argument. The diagram on page 60 shows the
first birds at about 150 mya. Therefore there is a gap of *75 million years*
between Longisquama and the first birds. Where are all the intermediates?
GM>The caption inside says:
>
>"The painting on the cover depicts Longisquama, a tiny (less than six inches
>long creature that lived in the Triassic period some 225 million years ago.
>It was a thecodont, a memeber of a group that was descended fromearly
>reptiles and included the ancestors of the dinosaurs. Unlike typical
>retiles, most thecodonts were 'warm-blooded,' like mammals and birds. And
>so too, it appears, were the dinosaurs. (see 'Dinosaur Renaissance,' by
>Robert T. Bakker, p. 58) Longisquama had plumelike devices on its back
It had an extended *ridge of scales* on its back, like other "finbacks":
"The first predators capable of killing relatively large prey were the finback
pelycosaurs of the family Sphenacodontidae, typified by Dimetrodon, whose
tall-spined fin makes it popular with cartoonists." (Bakker R.T., "Dinosaur
Renaissance," Scientific American, April 1975, Vol. 232, No. 4, p59)
GM>and a covering of insulating scales; such scales were a stage in the evolution of
>feathers.
The article is full of such question-begging assertions. There is no actual
evidence that "scales were a stage in the evolution of feathers". As I have
pointed out (but you just ignore as usual), in a recent study Brush has concluded
that:
"The molecular evidence questions the simple, direct relation of the
specialized statures of birds to reptile scale. I will provide arguments to
show that reptilian scales and feathers are related only by the fact that
their origin is in epidermal tissue. Every feature from gene structure and
organization, to development, morphogenesis and tissue organization is
different. I believe that while there is phenotypic similarity in some scales,
that feathers are unique to birds and deserve consideration as an
evolutionary novelty." (Brush A.H., "On the origin of feathers," Journal of
Evolutionary Biology, 9, 1996, p132)
GM>Longisquama is part of the evidence that dinosaurs were not
>reptiles but a novel 'warm-blooded' group, and that they are not really
>extinct after all--that the birds are a living group of dinosaurs." "The
>Cover", Scientific American April 1975, p. 4
This is an example of the muddled thinking that is evident in the article.
Longisquama was not even a "dinosaur":
"So what exactly is a dinosaur? And how do paleontologists decide
on the groups they belong to? There are four features that determine
what counts as a dinosaur:
Dinosaurs lived only in the Mesozoic Era. Dinosaur remains have
been discovered in rocks which range in age from the latest part of
the Triassic Period (about 220 mya) throughout the Jurassic Period
and up to the end of the Cretaceous Period (66 mya) - spanning
approximately 155 million years of Earth history. Therefore any
prehistoric creature which comes from rocks which can be dated at
older then 220 million years or younger than 66 million years is very
unlikely to be a dinosaur...
All dinosaurs walk on upright, pillar-like legs. That is the final and
most distinctive characteristic of all. Among the reptiles, only
dinosaurs have managed to arrange their legs in such a way that they
are held directly beneath their body. All other reptiles have their legs
splayed outward at an angle from the sides of the body, so that their
feet are wide apart."
(Norman D., "Dinosaur!," Boxtree: London, 1991, p48)
GM>Bakker in his article has the following caption (Robert T. Bakker, "Dinosaur
>Renaissance," Scientific American, April, 1975, p. 68)
>
>"Longisquama, a small animal whose fossil was discovered in middle Triassic
>lake beds in Turkestan by the Russian paleontologist A. Sharov, was a
>thecodont. ITs body was covered by long overlapping scales that were
>keeled, suggesting that they constituted a structural stage in the evolution
>of feathers."
What you conveniently left out was the remainder of the caption:
"...The long devices along the back were V-shaped in cross section; they
may have served as parachutes and also as threat devices, as shown here."
(Bakker R.T., "Dinosaur Renaissance," Scientific American, April
1975, Vol. 232, No. 4, p68)
What is important to note here is that Bakker is *not* claiming that the "The
long devices along the back" are the proto-feathers, but the "long overlapping
scales" that Longisquama's "body was covered by".
GM>And speaking of Longisquama,
>
>"More important is the covering of long, overlapping, keeled scales that
>trapped an insulating layer of air next to its body. These scales lacked
>the complex anatomy of real feathers, but they are a perfect ancestral stage
>for the insulation of birds."(ibid., p. 70
This quote actually asserts the *exact opposite* of what you are claiming.
Your claim was that what Bakker calls "the long devices along the back",
were the proto-feathers, *not* the "long overlapping scales" that Longisquama's
"body was covered by":
--------------------------------------------------------------------------
To: evolution@calvin.edu
From: grmorton@waymark.net (Glenn Morton)
Subject: half-evolved feather pt 2
[...]
I have chased a bit back into the literature looking for info on the
Longisquama feather-like scales. What I found is really fascinating.
[...]
The figure on page 88 has the following caption says that it possessed a
unique gliding mechanism of "a double series of long scalelike structures
that were unfolded in butterfly fashion to form a gliding wing." P. 88
the scales are as long as the animal and each one is separate from the other
scales and looks like a feather.
Now, the above should go some distance towards answering what Kenyon and
Davis ask of the fossil record,
"If only we could find a fossil showing scales developing the properties of
feathers, or lungs that were intermediate between the very different
reptilian and avian lungs, then we would ahve more to go on. But the fossil
record gives no evidence for such changes." Percival Davis and Dean H.
Kenyon, Of Pandas and People, Dallas Haughton Publishing, 1993, p. 106
[...]
glenn
--------------------------------------------------------------------------
In fact Bakker admits that even these "long, overlapping, keeled scales...lacked
the complex anatomy of real feathers", and all they were was a "ancestral stage
for the insulation of birds." But Feduccia and Martin, who you claimed were
"the two most widely acknowledged experts on avian evolution" (19 Apr 1998;
Re: half-evolved feathers), deny that feathers were originally for insulation. In
respect of the so-called feathered dinosaurs in China, Shipman wrote:
"Feduccia and Martin, however, remain deeply dubious about the
identification of the alleged feathers. "There is a 99 per cent
chance it's incorrect," says Feduccia, unable to conceive how a
tissue so well designed for flight could have evolved initially to
serve another purpose. "Everything about them indicates an
aerodynamic function," he says. "They're lightweight, they're
excellent airfoils, they produce high lift at low speeds, and they
have a Velcro-like quality that lets them be reassembled. Feathers
have an almost magical construction which is all aerodynamic in
function. It would be gross evolutionary overkill to produce
feathers like this for insulating a hot-blooded dino." (Shipman P.,
"Birds do it...did dinosaurs?", New Scientist, Vol 153, No 2067,
1 February 1997, p30)
GM>Surely a researcher should consult Scientific American and have been alerted
>to this possibility and then at least addressed it in their many, many books
>since 1975 claiming that there was no half-evolved feather. At what point do
>we say that they didn't do their job well?
Maybe it's *you* who haven't done your "job well"? Maybe they read the
"Scientific American" article and were not impressed by it. Indeed, Bakker
doesn't seem all that impressed by it either. By my calculations, Longisquama
only occupies about 2% of the article!
GM>Longisquama also appeared in L. B. Halstead, "The evolution and ecology of
>the dinosaurs, (London:Peter Lowe, 1975).
>
>As mentioned the other day, Longisquama was discussed in "Une Nouvelle
>interpretation de Longisquama insignis, reptile enigmatique du Trias
>superieur d'Asie Centrale," Comptes Rendes Acad. Sci. Paris, 305(1987) Serie
>II p. 65-70.
>
>I got this article today and it is in English.
It's all a bit thin for what is supposed to be your best example of an "incipient,
developingor transitional structures" such as a "half-scales/half-feather"!
As I have pointed out before, neither Colbert's "Evolution of the Vertebrates"
(1975) or Carroll's "Vertebrate Paleontology" (1988), even list Longisquama in
the index! Indeed, both dismiss known thecodonts as ancestral of birds:
"It has long been evident that birds are descended from archosaurian
reptiles, and for many years it has been thought that they had a
thecodont ancestry. Recent studies, however, present convincing
evidence that birds are the direct descendants of small theropod
dinosaurs." (Colbert E.H., "Evolution of the Vertebrates: A History of the
Backboned Animals Through Time," 1980, p184)
"There are no features of primitive thecodonts that preclude them from
being the ultimate ancestors of both dinosaurs and birds, but no thecodonts
can be demonstrated as sharing a unique, common ancestry with birds. The
features that they share are all primitive for archosaurs in general." (Carroll,
R.L., "Vertebrate Paleontology and Evolution," 1988, p340-341).
Since the world's leading paleontological authorities like Carroll and Colbert
do not acknowledge that Longisquama in particular, or thecodonts in general,
demonstrate "incipient, developing or transitional structures-such as half-scales
/half-feathers" (Morris H.M. & Parker G.E., "What is Creation Science?," 1987,
p11), it is manifestly unreasonable for you to demand that YECs acknowledge
it.
Gish in fact *does* refer indirectly to to Maderson's article in American
Naturalist containing Longisquama, but based on Maderson's own admission
that it was only an *attempt* to explain how a reptile scale *might* have given
rise to a proto-feather, Gish no doubt concluded that there was not even a
case to answer:
"P. F. A Maderson has also suggested a scenario for the origin of
feathers from reptilian scales. He is frank enough to admit, however,
that:
`I emphasize that this model only attempts to explain how an
archosaurian scale might have given rise to a proto-feather. The end
product as shown in figure 1d resembles a feather in the usual sense
of the word only in that it is a highly specialized keratinous
integumentary appendage. We cannot as yet offer any plausible
explanation for the origin of the unique shaft; barbs, and barbules
without which modern feathers would have neither aerodynamic nor
insulatory function. (P.F.A Maderson, The American Naturalist 146:427 (1972)),
in Gish D.T., "Evolution: The Fossils Still Say NO!," 1995, p136)
GM>Some uncompleted business: Stephen Jones had asked for the reference on
>Longisquama from the recent Nature. It is Alan Feduccia and Larry D.
>Martin, Mark Norell et al, "Theropod-Bird Link Reconsidered," Nature
>391(Feb. 19, 1998), p. 754-755
Thanks. I'll look it up.
Steve
--------------------------------------------------------------------
Stephen E (Steve) Jones ,--_|\ sejones@ibm.net
3 Hawker Avenue / Oz \ Steve.Jones@health.wa.gov.au
Warwick 6024 ->*_,--\_/ Phone +61 8 9448 7439
Perth, West Australia v "Test everything." (1Thess 5:21)
--------------------------------------------------------------------
--_=_=_=IMA.BOUNDARY.HTML_4820800=_=_=_
Content-Type: text/html; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Glenn
On Thu, 30 Apr 1998 20:33:58 -0500, Glenn Morton wrote:
GM>Concerning claims that Longisquama was ignored over the years and thus a
>young-earth creationist making the claim that there is no half-evolved
>feather should not be held accountable for knowing about it...
The actual claim was that:
"There are no true transitional forms (that is, in the sense of forms containing
incipient, developing or transitional structures-such as half-scales/half-feathers,
or half-legs/ half-wings) anywhere among all the billions of known fossil forms."
(Morris H.M. & Parker G.E., "What is Creation Science?," 1987, p11)
The emphais is on the "true". M&P would no doubt agree that there are
*claimed* transitional forms, but they believe that these are not "true transitional
forms":
"...the stratomorphic intermediate evidences are not without difficulty for
evolutionary theory. First, none of the stratomorphic intermediates have
intermediate structures. Although the entire organism is intermediate in
structure, it's the *combination* of structures that is intermediate, not the
nature of the structures themselves. Each of these organisms appears to
be a fully functional organism full of fully functional structures.
Archaeopteryx, for example, is thought to be intermediate between reptiles
and birds because it has bird structures (e.g, feathers) and reptile
structures (e.g., teeth, forelimb claws). Yet the teeth, the claws, the
feathers and all other known structures of Archaeopteryx appear to be fully
functional. The teeth seem fully functional as teeth, the claws as claws,
and the feathers as any flight feathers of modern birds. It is merely the
combination of structures that is intermediate, not the structures
themselves." (Wise K.P., "The Origin of Life's Major Groups," in Moreland
J.P., ed., "The Creation Hypothesis," 1994, p227)
This is a YEC claim. One proved major transitional form would be *fatal* to
YEC which holds that all the major "kinds" were created de novo within
6 x 24-hour days, about 10,000 years ago.
My Mediate Creation position is not that there are no transitional forms, but
there are not enough of them. What the fossil record pervasively reveals
is therefore not *Darwinian* evolution:
"Because Darwinian evolution is a purposeless, chance-driven process,
which would not proceed directly from a starting point to a destination,
there should also be thick bushes of side branches in each line. As Darwin
himself put it, if Darwinism is true the Precambrian world must have "swarmed
with living creatures" many of which were ancestral to the Cambrian animals."
(Johnson P.E., "Darwinism's Rules of Reasoning", in Buell J. & Hearn V., eds.,
"Darwinism: Science or Philosophy?", 1994, pp13-14)
But having said that, while not ruling out such "true transitional forms" *to date*
I have seen no good evidence that there are "forms containing incipient,
developing or transitional structures-such as half-scales/half-feathers, or half-
legs/ half-wings."
GM>In April 1975, Longisquama made the cover of Scientific American. Pretty
>good for a 225 million year old girl from Russia.
Which in itself defeats his own argument. The diagram on page 60 shows the
first birds at about 150 mya. Therefore there is a gap of *75 million years*
between Longisquama and the first birds. Where are all the intermediates?
GM>The caption inside says:
>
>"The painting on the cover depicts Longisquama, a tiny (less than six inches
>long creature that lived in the Triassic period some 225 million years ago.
>It was a thecodont, a memeber of a group that was descended fromearly
>reptiles and included the ancestors of the dinosaurs. Unlike typical
>retiles, most thecodonts were 'warm-blooded,' like mammals and birds. And
>so too, it appears, were the dinosaurs. (see 'Dinosaur Renaissance,' by
>Robert T. Bakker, p. 58) Longisquama had plumelike devices on its back
It had an extended *ridge of scales* on its back, like other "finbacks":
"The first predators capable of killing relatively large prey were the finback
pelycosaurs of the family Sphenacodontidae, typified by Dimetrodon, whose
tall-spined fin makes it popular with cartoonists." (Bakker R.T., "Dinosaur
Renaissance," Scientific American, April 1975, Vol. 232, No. 4, p59)
GM>and a covering of insulating scales; such scales were a stage in the evolution of
>feathers.
The article is full of such question-begging assertions. There is no actual
evidence that "scales were a stage in the evolution of feathers". As I have
pointed out (but you just ignore as usual), in a recent study Brush has concluded
that:
"The molecular evidence questions the simple, direct relation of the
specialized statures of birds to reptile scale. I will provide arguments to
show that reptilian scales and feathers are related only by the fact that
their origin is in epidermal tissue. Every feature from gene structure and
organization, to development, morphogenesis and tissue organization is
different. I believe that while there is phenotypic similarity in some scales,
that feathers are unique to birds and deserve consideration as an
evolutionary novelty." (Brush A.H., "On the origin of feathers," Journal of
Evolutionary Biology, 9, 1996, p132)
GM>Longisquama is part of the evidence that dinosaurs were not
>reptiles but a novel 'warm-blooded' group, and that they are not really
>extinct after all--that the birds are a living group of dinosaurs." "The
>Cover", Scientific American April 1975, p. 4
This is an example of the muddled thinking that is evident in the article.
Longisquama was not even a "dinosaur":
"So what exactly is a dinosaur? And how do paleontologists decide
on the groups they belong to? There are four features that determine
what counts as a dinosaur:
Dinosaurs lived only in the Mesozoic Era. Dinosaur remains have
been discovered in rocks which range in age from the latest part of
the Triassic Period (about 220 mya) throughout the Jurassic Period
and up to the end of the Cretaceous Period (66 mya) - spanning
approximately 155 million years of Earth history. Therefore any
prehistoric creature which comes from rocks which can be dated at
older then 220 million years or younger than 66 million years is very
unlikely to be a dinosaur...
All dinosaurs walk on upright, pillar-like legs. That is the final and
most distinctive characteristic of all. Among the reptiles, only
dinosaurs have managed to arrange their legs in such a way that they
are held directly beneath their body. All other reptiles have their legs
splayed outward at an angle from the sides of the body, so that their
feet are wide apart."
(Norman D., "Dinosaur!," Boxtree: London, 1991, p48)
GM>Bakker in his article has the following caption (Robert T. Bakker, "Dinosaur
>Renaissance," Scientific American, April, 1975, p. 68)
>
>"Longisquama, a small animal whose fossil was discovered in middle Triassic
>lake beds in Turkestan by the Russian paleontologist A. Sharov, was a
>thecodont. ITs body was covered by long overlapping scales that were
>keeled, suggesting that they constituted a structural stage in the evolution
>of feathers."
What you conveniently left out was the remainder of the caption:
"...The long devices along the back were V-shaped in cross section; they
may have served as parachutes and also as threat devices, as shown here."
(Bakker R.T., "Dinosaur Renaissance," Scientific American, April
1975, Vol. 232, No. 4, p68)
What is important to note here is that Bakker is *not* claiming that the "The
long devices along the back" are the proto-feathers, but the "long overlapping
scales" that Longisquama's "body was covered by".
GM>And speaking of Longisquama,
>
>"More important is the covering of long, overlapping, keeled scales that
>trapped an insulating layer of air next to its body. These scales lacked
>the complex anatomy of real feathers, but they are a perfect ancestral stage
>for the insulation of birds."(ibid., p. 70
This quote actually asserts the *exact opposite* of what you are claiming.
Your claim was that what Bakker calls "the long devices along the back",
were the proto-feathers, *not* the "long overlapping scales" that Longisquama's
"body was covered by":
--------------------------------------------------------------------------
To: evolution@calvin.edu
From: grmorton@waymark.net (Glenn Morton)
Subject: half-evolved feather pt 2
[...]
I have chased a bit back into the literature looking for info on the
Longisquama feather-like scales. What I found is really fascinating.
[...]
The figure on page 88 has the following caption says that it possessed a
unique gliding mechanism of "a double series of long scalelike structures
that were unfolded in butterfly fashion to form a gliding wing." P. 88
the scales are as long as the animal and each one is separate from the other
scales and looks like a feather.
Now, the above should go some distance towards answering what Kenyon and
Davis ask of the fossil record,
"If only we could find a fossil showing scales developing the properties of
feathers, or lungs that were intermediate between the very different
reptilian and avian lungs, then we would ahve more to go on. But the fossil
record gives no evidence for such changes." Percival Davis and Dean H.
Kenyon, Of Pandas and People, Dallas Haughton Publishing, 1993, p. 106
[...]
glenn
--------------------------------------------------------------------------
In fact Bakker admits that even these "long, overlapping, keeled scales...lacked
the complex anatomy of real feathers", and all they were was a "ancestral stage
for the insulation of birds." But Feduccia and Martin, who you claimed were
"the two most widely acknowledged experts on avian evolution" (19 Apr 1998;
Re: half-evolved feathers), deny that feathers were originally for insulation. In
respect of the so-called feathered dinosaurs in China, Shipman wrote:
"Feduccia and Martin, however, remain deeply dubious about the
identification of the alleged feathers. "There is a 99 per cent
chance it's incorrect," says Feduccia, unable to conceive how a
tissue so well designed for flight could have evolved initially to
serve another purpose. "Everything about them indicates an
aerodynamic function," he says. "They're lightweight, they're
excellent airfoils, they produce high lift at low speeds, and they
have a Velcro-like quality that lets them be reassembled. Feathers
have an almost magical construction which is all aerodynamic in
function. It would be gross evolutionary overkill to produce
feathers like this for insulating a hot-blooded dino." (Shipman P.,
"Birds do it...did dinosaurs?", New Scientist, Vol 153, No 2067,
1 February 1997, p30)
GM>Surely a researcher should consult Scientific American and have been alerted
>to this possibility and then at least addressed it in their many, many books
>since 1975 claiming that there was no half-evolved feather. At what point do
>we say that they didn't do their job well?
Maybe it's *you* who haven't done your "job well"? Maybe they read the
"Scientific American" article and were not impressed by it. Indeed, Bakker
doesn't seem all that impressed by it either. By my calculations, Longisquama
only occupies about 2% of the article!
GM>Longisquama also appeared in L. B. Halstead, "The evolution and ecology of
>the dinosaurs, (London:Peter Lowe, 1975).
>
>As mentioned the other day, Longisquama was discussed in "Une Nouvelle
>interpretation de Longisquama insignis, reptile enigmatique du Trias
>superieur d'Asie Centrale," Comptes Rendes Acad. Sci. Paris, 305(1987) Serie
>II p. 65-70.
>
>I got this article today and it is in English.
It's all a bit thin for what is supposed to be your best example of an "incipient,
developingor transitional structures" such as a "half-scales/half-feather"!
As I have pointed out before, neither Colbert's "Evolution of the Vertebrates"
(1975) or Carroll's "Vertebrate Paleontology" (1988), even list Longisquama in
the index! Indeed, both dismiss known thecodonts as ancestral of birds:
"It has long been evident that birds are descended from archosaurian
reptiles, and for many years it has been thought that they had a
thecodont ancestry. Recent studies, however, present convincing
evidence that birds are the direct descendants of small theropod
dinosaurs." (Colbert E.H., "Evolution of the Vertebrates: A History of the
Backboned Animals Through Time," 1980, p184)
"There are no features of primitive thecodonts that preclude them from
being the ultimate ancestors of both dinosaurs and birds, but no thecodonts
can be demonstrated as sharing a unique, common ancestry with birds. The
features that they share are all primitive for archosaurs in general." (Carroll,
R.L., "Vertebrate Paleontology and Evolution," 1988, p340-341).
Since the world's leading paleontological authorities like Carroll and Colbert
do not acknowledge that Longisquama in particular, or thecodonts in general,
demonstrate "incipient, developing or transitional structures-such as half-scales
/half-feathers" (Morris H.M. & Parker G.E., "What is Creation Science?," 1987,
p11), it is manifestly unreasonable for you to demand that YECs acknowledge
it.
Gish in fact *does* refer indirectly to to Maderson's article in American
Naturalist containing Longisquama, but based on Maderson's own admission
that it was only an *attempt* to explain how a reptile scale *might* have given
rise to a proto-feather, Gish no doubt concluded that there was not even a
case to answer:
"P. F. A Maderson has also suggested a scenario for the origin of
feathers from reptilian scales. He is frank enough to admit, however,
that:
`I emphasize that this model only attempts to explain how an
archosaurian scale might have given rise to a proto-feather. The end
product as shown in figure 1d resembles a feather in the usual sense
of the word only in that it is a highly specialized keratinous
integumentary appendage. We cannot as yet offer any plausible
explanation for the origin of the unique shaft; barbs, and barbules
without which modern feathers would have neither aerodynamic nor
insulatory function. (P.F.A Maderson, The American Naturalist 146:427 (1972)),
in Gish D.T., "Evolution: The Fossils Still Say NO!," 1995, p136)
GM>Some uncompleted business: Stephen Jones had asked for the reference on
>Longisquama from the recent Nature. It is Alan Feduccia and Larry D.
>Martin, Mark Norell et al, "Theropod-Bird Link Reconsidered," Nature
>391(Feb. 19, 1998), p. 754-755
Thanks. I'll look it up.
Steve
--------------------------------------------------------------------
Stephen E (Steve) Jones ,--_|\ sejones@ibm.net
3 Hawker Avenue / Oz \ Steve.Jones@health.wa.gov.au
Warwick 6024 ->*_,--\_/ Phone +61 8 9448 7439
Perth, West Australia v "Test everything." (1Thess 5:21)
----------------------------------------------------------------------_=_=_=IMA.BOUNDARY.HTML_4820800=_=_=_--