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Stephen Czerkas' dromaeosaurs = birds but not dinosaurs
I am awaiting my copy of his compendium, edited by
Sylvia. However: I do not, on the basis of his
forthright abstract, grasp how he can posit a
non-dinosaur origin for dinosaur dromaeosaurs, unless
his converted clade names are not constructed
according to rigorous phylogenetic systematics. He is
claiming that a dromaeosaur specimen has "flight"
feathers on its manus region -- but how can "flight"
feathers exist on an animal without wings? I suggest a
familiarity with the work of Jeremy Rayner on flight
aeodynamics and Richard Prum, Alan Brush, et al. on
feather topology would be in order. As Mary Schweitzer
et al. have said, integumentary structures were
present among various taxa, and feathers were part of
these structures. Feathers, unless I am mistaken, are
remiges, retrices, and body contour structures, with
varieties of semiplues, filoplumes, bristles.
Different body areas had/have different types of
feathers. (I am drawing here from Alan Brush's Ostrom
compendium paper.) And, unless I am mistaken, Stephen
is claiming that dromaeosaurs were already
"birds"...I'm afraid that broad generalities, without
copious character analyses, are not proof, do not meet
evidentiary standards of phylogenetic systematics (and
the constant use of the word "controversial", while
perhaps useful for those who like pictures and not
words, is innane; there is nothing "controversial"
about Aves being a clade in Theropoda).
Of course, I keenly
anticipate reading Stephen's paper -- in hopes, he
will define "dromaeosaur" and "bird" and "dinosaur",
explain why a dromaeosaur is not a dinosaur and a
"bird" is not a dinosaur.
I have talked with someone who
actually has a copy of the book. Missing from
Stephen's work are analyses: no operational taxonomic
units; no characters presented in analyses (Thomas
Holtz has 386+ osteological characters, and
Livezey/Zusi are working with ~1416 anatomical
characters of living dinosaurs). Stephen has no
appendices or tables of data matrix using PAUP 3.1.1
for his specimens, no parsimonious trees subjected to
MacClade 3.07 to ascertain character state
transformations accelerated (ACCTRAN) or delayed
(DELTRAN), no consistency index with MacClade or
homoplasy index with PAUP (methods and materials
pivotal to Thomas Holtz's pioneering analyses). In
short, no scientific evidence to prove a) dromaeosaurs
could fly (even if some could -- it is not
out-of-the-question -- this does not remove Aves from
Theropoda); b) that Aves are not Theropoda, that
dromaeosaurs are not Theropoda.
Of course, I shall have to wait to see the actual
paper on this subject to see if, perhaps, something
has been overlooked.
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