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Re: Feduccia et al. (2005) Critique
At 02:25 PM 10/11/2005 +0000, Michael Mortimer wrote:
The BAND movement simply refuses to die, invigorated as it is by its
transformation into MANIAC. It seems like just yesterday that I shot down
Martin's latest publication (http://dml.cmnh.org/2005May/msg00317.html),
now I get to do the same for Feduccia's. Well, technically Lingham-Soliar
and Hinchcliffe are coauthors, but I mostly refer to Feduccia himself
below for simplification.
Feduccia, A., Lingham-Soliar, T., and Hinchliffe, J.R. (2005). Do
feathered dinosaurs exist? Testing the hypothesis on neontological and
paleontological evidence. J. Morphology (in press).
The article starts out with an introduction full of fun inaccuracy.
When it comes to Sinornithosaurus' holotype, it's hard to see where
Lingham-Soliar is going. No doubt affecting this is the fact the figure
is hopelessly blurry. He claims the base of the illustrated tuft of
filaments is actually an eroded area with filaments that run diagonal to
the main tuft.
This *may* be a second tuft hidden in the matrix under the first.
Perhaps true (I can't evaluate the figure), but Xu et al. (2001)
mentioned several instances of tufts. Lingham-Soliar argues a case of
filaments branching from a central one is due to the "laws of chance",
which is fine, but again Xu et al. stated several of these occurances
were present. He also states that integumentary structures are found
throughout the substrate, including fainter (more eroded?) ones covering
almost the entire surface. I don't see how this argues against them
Given the quality of Lingham-Soliar's figures for Sinornithosaurus, I
found his statement "... the conclusions arrived at by Xu et al. (2001)
are not only seriously flawed and technically unsound but misleading to
the reader both by the extremely poor quality of their figures
(uninformative in vital respects) ..." hilariously ironic.
Something else that puzzles me about the _Sinornithosaurus_ section is the
fact that the "protofeathers" originally depicted in Xu et al. appear to
have pigmentation, whereas a lot of the strands illustrated in the current
paper don't seem to. Unfortunately, as you point out, the pictures aren't
the best, and make it hard to tell what's going on. Some of the strands
pointed to may have become separated from the larger tuffs before
Pelecanimimus is less convincing. There are supposedly overlapping scales
on the forearm, some with "fingerlike projections". These are
photographed (though not in relation to any bones), but they don't
immediately strike me as scales. At least not dinosaur scales. They seem
to be diamond-shaped, like you'd find on a gar. Maybe Pelecanimimus did
have rhomboid overlapping arm scales. I can't help but think of
Santanaraptor though (which Feduccia et al. mention as an unnamed
theropod), which the authors describe as having "a thin epidermis, formed
mostly by irregular quadrangles bordered by deep grooves in a criss-cross
pattern." Amusingly, if the authors are right, this destroys their prior
argument dinosaurs lacked overlapping scales, so couldn't evolve feathers
(under Maderson's outdated developmental scheme).
The caption for figure 15B states "Skeletal reconstruction of
_Pelecanimimus_ (modified from Carroll, 1988)", but _Pelecanimimus_ wasn't
described until 1994, and the closest thing I can find in Carroll is an
illustration of _Struthiomimus_ (figure 14-9). Is it kosher to label a
modified reconstruction as being of one dino when in fact it's of another,
or am I being pedantic?
Regarding _Caudipteryx_, Feduccia et al. state that "According to recent
paleontological theory, everything related to the lineage of avian origins
must be developing flight from the ground up and all aerodynamic
adaptations, regardless of their aerodynamic precision, must have evolved
in a context other than flight, as preadaptations. 'Non-avian theropods
such as _Velociraptor_, _Compsognathus_, and _Tyrannosaurus_ were clearly
terrestrial cursors. Thus, the ancestral mode of life of birds was that of
a cursorial biped. Inferences about the habits of _Archaeopteryx_ should be
made within this framework and not the inverse" (Chiappe, 1997, p. 110).
This line of reasoning completely ignores the obvious bird-like features of
_Caudipteryx_, the fact that oviraptosaurs are likely secondarily
flightless birds (with _Caudipteryx_ as a basal member), and the fact that
it is not parsimonious to assume that the intricate aerodynamically
designed detail of the positioning of the remiges of the avian wing evolved
in a nonflighted theropod (Fig. 26)."
The Chiappe paper was published in 1997, and _Caudipteryx_ was described in
1998. Isn't it a bit unfair to criticize Chiappe for ignoring _Caudipteryx_
when it hadn't even been described yet?
[snip the rest]