[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: MORE "Dinosaur Planet"dinosaurs!!!(This time with feathers)



Timothy Bridgeman replied-

> > There are now eleven specimens of Microraptor/Cryptovolans described in
> the
> > literature (Xu et al., 2000; Czerkas et al., 2002; Hwang et al., 2002;
Xu
> et
> > al., 2003).  At least six of these have undeniable feathers.  Three are
> from
> > Shangheshou, three are from Dapingfang.  NGMC 91 (Dave) is from
> Fanzhangzi.
> > So the best evidence of feathered dromaeosaurs does not come from the
same
> > quarry or even the same city as NGMC 91, and where exactly the
> > "Archaeoraptor" specimen is from is unknown (no precise locality data
were
> > taken by the collector before it was forged and sold).
> > Do you really think that it's likely the feathers of Microraptor gui's
> > holotype are bird feathers that happened to be placed in exactly the
right
> > place to have perfect wings with primaries, secondaries and coverts,
> similar
> > arrangements on the legs, and retrices on the distal tail?  It even has
> > little pennaceous feathers on its head.  There are no other bones in the
> > matrix, no extra birds (note the X-ray CAT scan).
>
> I was under the impression that "Dave" specimen was one of the best
evidence
> in favor of feathered dinosaurs,since it could be the most undeniably
> classified as a dinosaur,unlike the much more birdlike Caudipteryx or even
> Microraptor.

Dromaeosaurs like NGMC 91 are more birdlike (or at least more
Archaeopteryx-like) than oviraptorosaurs like Caudipteryx.  Ironically,
Feduccia et al. (NOTE: "Feduccia et al." is used in the post to represent
the group of people who believe birds aren't dinosaurs, not in reference to
an actual Feduccia et al. article) would have an easier time trying to
classify NGMC 91 as a bird, except for the fact Sinornithosaurus is just as
birdlike.  But as you noted yourself, the remiges and retrices aren't as
obviously pennaceous in NGMC 91 (though still visible, particularily in the
online closeup of figure 5a from Ji et al., 2001).  So it's just easier to
argue using utterly undeniable feathers like those of Microraptor and
Cryptovolans.
Since you now know (at least some of) these Microraptor/Cryptovolans
specimens don't come from the same source as "Archaeoraptor", and have been
unable to provide a realistic scenario by which bird feathers are arranged
on the holotype of M. gui in a perfectly lifelike arrangement without
leaving any bird bones behind, do you believe Microraptor/Cryptovolans was
really feathered?  If not, why not?

> > You're misunderstanding something, though your wording makes it
difficult
> to
> > tell just what it is.
> > The feathers on Microraptor gui's holotype (IVPP V13352) the four-winged
> > dinosaur as you call it) ARE part of the original fossil.  In fact, the
> > feathers are preserved on the same slabs as the bones, and some were
even
> > under matrix when prepared, as noted above.
>
> I refer you to www.dinodata.net to the listing for the genus
Microraptor.In
> the section on M.gui,it states:
> "The integumentation of M.gui is based on the holotype and referred
> specimen...." Unless I have misinterpreted something,it should say "The
> integumentation of M.gui displays two types plumulaceous and pennaceous
> feathers with a length of...." without saying that it is based on the
> holotype and referred specimen.Using that term implies that it was not
part
> of the original fossil,but reconstructed based on other,similar specimens.

Your interpretation of DinoData's sentence is incorrect.  Again, I recommend
reading the original literature (free online
http://www.cals.ncsu.edu/course/zo501/4WingedDino.pdf ).
It means both the holotype and referred specimen of M. gui preserve
feathers.  Thus, M. gui's feather morphology is based on the holotype and
referred specimen of that species.

> >It's feathers have nothing to
> > do with the Yanornis top half of "Archaeoraptor" (IVPP V12444), or the
> > Microraptor tail of "Archaeoraptor".  I think the tail section of
> > "Archaeoraptor" was the counterslab of the holotype of Microraptor
> > zhaoianus' tail (IVPP V12330), but am unsure.  The same could be said of
> the
> > referred specimen of M. gui (IVPP V13320).  M. gui's feathers are not
> based
> > on the "Archaeoraptor" specimen in any way.
> > I see nothing in your paragraph showing where feathers were faked, and
> > continue to believe making feathers under sediment is beyond our current
> > technology, as is constructing such elaborate sets of feathers on both
> slab
> > and counter slab.  These are actual feather remains, remember, not
> > impressions.
>
> I did not imply that ALL feather traces were fake,I was referring to the
> possibility of fakery(one should not just pretend that the
> "Archaeoraptor"debacle never happenned.)

The "Archaeoraptor" situation wasn't really a debacle.  The specimen's
description was never accepted into the scientific literature, the
specimen's morphology was never used in a technical article to support the
dinosaur origin of birds, the forgery was suspected by proponents of the
dinosaur-bird connection, and exposed by them too.  Feduccia et al. like to
act as if "Archaeoraptor" was a huge embarrassment and blow to the
dinosaur-bird theory, but this simply isn't true.  The method by which it
was faked can be tested on any specimen, and the method just isn't
applicable to specimens like M. gui's holotype or NGMC 91, because they have
feathers on the same slab as the bones.  So saying the "Archaeoraptor"
situation should make us doubt these feathered dinosaurs more isn't logical.
It's like saying "because Piltdown Man was a combination of human and
orangutan bones, we should be careful about the possibility this articulated
Australipithecus skeleton is faked too."

> > There are always variations, but trying to argue Caudipteryx isn't a
> > dinosaur is like trying to argue a dog isn't a mammal.
> >Let me put it
> > simply, the supposed bird-like characters noted by Feduccia et al. are
> > either-
> > 1. Also found in oviraptorosaurs (teeth with constricted roots and no
> > serrations; no maxillary or dentary teeth; external mandibular fenestra
> > present; enlarged premaxilla and reduced maxilla; ball-shaped femoral
> head).
> > 2. Unknown (but unlikely) in Caudipteryx (ventrally directed foramen
> > magnum).
> > 3. Circular reasoning (pennaceous feathers).
> > 4. Not present in Caudipteryx (pygostyle; four carpals; no pubic boot;
> > hypopubic cup; reduced fibula; reduced calcaneum; reversed hallux).
> > .... except for the shortened tail, which is actually shorter than other
> > oviraptorosaurs and Archaeopteryx, so is like advanced birds.  Also,
there
> > are fewer dorsal vertebrae (and thus more cervical vertebrae) and a
> reduced
> > third manual digit, that are both like very advanced birds (more
advanced
> > than Confuciusornis).  But Caudipteryx lacks a ton of features these
kinds
> > of birds have (heterocoelous cervicals, pygostyle, strut-like coracoid,
> > carpometacarpus, trochanteric crest, tibiotarsus, tarsometatarsus,
> reversed
> > hallux, etc.), so is certainly not part of that group.  I would really
> like
> > to see your list of characters in which Caudipteryx is more like birds
> than
> > oviraptorosaurs.
>
> Strangely enough,you have already listed for bird features than dinosaur
for
> Caudipteryx.
> In common with oviraptorsaurs you list five characters in common.Then you
> list overall around ten features in common with various groups of birds.(I
> agree that Caudipteryx does not belong to the same group of advanced birds
> as Confuciusornis.)

Seems you need a lesson in phylogenetics.  All but one of the birdlike
characters of Caudipteryx I listed (the exception being the shortened tail)
are NOT useful at all to those who believe it is a bird.  This is because
they are only shared with birds too advanced to be Caudipteryx's relatives.
For an extreme (and false) example, it would be like saying Dimetrodon is a
primitive mammal because it has the upright posture of humans.  This
character is useless when arguing Dimetrodon is a mammal because the
primitive mammals it could possibly be related to don't have a human's
posture.  So the vertebral count and reduced third finger of Caudipteryx
aren't seen in confuciusornithids, and therefore can't be used to support
the idea it is a bird more primitive than Confuciusornis.
All the characters I listed come from Feduccia et al.'s various papers that
tried to show Caudipteryx was a bird, and I don't think you understood what
I was saying about them.  They are all supposed to be distinct "bird
characters of Caudipteryx", but I show they are not.  The first group
(listed under number 1) are found in other oviraptorosaurs too, so cannot
support a bird identity over an oviraptorosaurian one.  The next (listed
undeer number 2) is not provable in Caudipteryx, but was probably absent.
The one after that (listed under number 3) is the only reason Feduccia et
al. want Caudipteryx to be a bird in the first place, and is unknown (though
not demonstrably absent) in other oviraptorosaurs.  Finally, the last seven
aren't even present in Caudipteryx, contrary to what Feduccia et al. say.

> > Here are some reasons Caudipteryx is more primitive than Archaeopteryx-
> > 1. dorsal process of jugal placed too far anteriorly
> > 2. more than nine caudals with transverse processes.
> > 3. distal caudal vertebrae with prezygopophyses over 40% of central
> length.
> > 4. more than twelve caudal vertebrae with prominent neural spines.
> > 5. more than eleven dorsoventrally elongate chevrons.
> > 6. short coracoid (maximum coracoid height <150% of length from anterior
> tip
> > to posterior edge of glenoid).
> > * This is also seen in the avian Sapeornis.
> > 7. unfused sternal plates.
> > * This is also seen in the avian Shenzhouraptor (=Jeholornis).
> > 8. metacarpal III not laterally bowed.
> > * This is also seen in several birds-  Sapeornis, Omnivoropteryx,
> > Patagopteryx, and Yixianornis.
> > 9. metacarpal I > 32% of metacarpal II's length.
> > * This is also seen in confuciusornithids.
> > 10. supratrochanteric process of ilium absent.
> > * This is also seen in Sapeornis.
> > 11. prominent ventral extension of preacetabular process.
> > 12. postacetabular process squared off.
> > 13. pubic boot projects anteriorly.
> > 14. no proximodorsal ischial process.
> > 15. obturator process placed more proximally.
> > 16. no capital ligament fossa on femoral head.
> > 17. pedal phalanx II-1 <90% of phalanx III-1's length.
> > 18. pedal phalanx II-2 <85% of phalanx II-1's length.
>
> Again,I would have to agree.

Then you believe differently than Feduccia et al., who place it closer to
modern birds than Archaeopteryx.
Now the question is- what characters does Caudipteryx have that keep it
outside Dinosauria?

> > >  I personally find the objections to the use of an animal with such an
> > > enormous amount of connective tissue for their study
irrelevent,because
> it
> > > still shows the extreme similarity of decayed connective tissue to
what
> > has
> > > been referred to as"protofeathers".
> >
> > The point is that having so much tissue above the braincase or tail of
> > Sinosauropteryx, or on the snout, arms and distal tail of NGMC 91, is
just
> > ludicrous.  The animals used for comparisons by Ruben and Lingham-Soliar
> are
> > either aquatic with a thick layer of insulation (dolphins, ichthyosaurs)
> or
> > have fins (sea snakes).  There just isn't that much collagen in the
> various
> > body parts of terrestrial reptiles.  Even the birds-aren't-dinosaurs
camp
> > was forced to admit Yixian coelurosaurs were insulated (though they
still
> > refused a feather identity, they alled it hair) at the 5th SAPE
symposium.
>
> > > For the same reason that not all Sinosauropteryx prima specimens show
> > > collagen remains(or "protofeathers",whichever floats your boat).Some
> > > specimens fossilise better than others.
> >
> > There are two described specimens, both of which show feathers.  The
often
> > cited third specimen is actually a different taxon ("Huaxiasaurus"?),
but
> > also has feathers.  A fourth specimen is known, but not described yet,
and
> > not illustrated well enough to tell if feathers are preserved.
> > My actual point was that the non-dinosaurian taxa all preserve the
"right"
> > type of integument if any is preserved.  The reptiles are scaled, the
> > pterosaurs and mammals furred, the birds feathered.  But none of these
has
> > "collagen" preserved.
>
> > >   For the same reason that the decayed connective tissues of the
buried
> > > dolphin are nearly identical to preserved Yixian bird and dromaeosaur
> > > feathers.The similarities mentioned above is my reason to suspect the
> > > possibility that the preserved Yixian dromeaosaurs especially,show
> > collagen
> > > traces.(I include "Dave"in this,as you are right about it not being
> > faked,I
> > > do not see a single identifiable feather in this specimen,only fibrous
> > tufts
> > > around the body and under the arms and fibers around the head and
neck.)
> >
> > But the decayed conective tissues of the dolphin are not like
coelurosaur
> > feathers.
> > In Sinosauropteryx, for instance, they come in two distinct thicknesses
> (.2
> > mm; <.1 mm).  In the dolphin, collagen fiber bundles were .03-.04 mm
wide,
> > much smaller.
> > These two types of filaments also have different distributions (thicker
> ones
> > only located close to body) and orientations (thicker ones at a higher
> angle
> > to the body wall).  This suggests an organization like downy feathers,
but
> > no mechanism for this arrangement has been put forth by collagen
> advocates.
> > In Sinosauropteryx, the feathers are the expected distance away from the
> > skeleton- close to the skull, hips and distal tail; far from the
shoulders
> > and proximal tail.  This is contra the expected distribution of an
> internal
> > fiber.
> > Also, Sinosauropteryx actually shows a regular striped pattern on its
> > feathered body (easily viewable in ultraviolet if I recall), with the
> > stripes missing ventrally (Longrich, 2002).  This has an obvious reason
if
> > they are counter-shaded striped integument, but not if they are internal
> > fibers.
> > Finally, the fibers of Shuvuuia (an alvarezsaurid theropod, which Martin
> et
> > al. don't believe is a bird) are made of keratin, as proven by chemical
> > analysis.

I notice you have no objections to my numerous critiques of the collagen
theory.  Do you accept the fact the Yixian coelurosaurs preserve integument,
and not connective tissue?  If not, why not?

> > Basically, your viewpoint is so highly flawed that not even its
supporters
> > can hold on to it.  Feduccia (2002) now admits Cryptovolans was
feathered,
> > and he, Czerkas (Czerkas et al., 2002) and Martin (pers. comm. at SVP
> 2002)
> > find it probable all maniraptorans were feathered.  Of course, they now
> > think all maniraptorans are birds, not dinosaurs.  No reasons to exclude
> > them from Dinosauria have been given, and I expect none to ever appear.
> > Feduccia has made it seem like feathered dromaeosaurs are a huge
surprise
> to
> > everyone, which will make everyone rethink their ideas, but this isn't
> true
> > at all.  It fits just fine with the last two decades of theories from
the
> > dinosaurs-are-birds camp.  Indeed, Feduccia and his colleagues are
either
> > incredibly ignorant, or are horrendous liers.  I recommend reading the
> > attached paper, which really gives a good impression of the state of
this
> > "debate".
>
> I would'nt say that my viewpoint is highly flawed,as it is all a matter of
> interpretation of the evidence.That more people than not agree with the
idea
> that not only are birds descended from dinosaursARE birds,is of little
> importance to me.While you could be right about it,I still can see other
> possibilities.

But to justify those possibilities as viable scientific hypotheses, you have
to be able to support them with evidence.  And so far, you've been unable to
support the following parts of your hypothesis-
- Microraptor/Cryptovolans does not preserve feathers.
- Caudipteryx isn't a dinosaur.
- The structures preserved on Yixian coelurosaurs are connective tissue.
Unless you can do such, your hypothesis is flawed, and should be rejected.

Mickey Mortimer