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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.

[big snip]

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 being feathers.
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 fossilization.


[snip]

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?



[snip]

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]