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Re: Kurochkin 2006 critique
Also, I'm not sure where Kurochkin has been in the last few decades,
Not in any place with English-language literature, apparently.
Both of these paragraphs illustrate a fallacy of Kurochkin's- that if a
structure is found to be homoplasious in two taxa, its homology in a third
taxon can be safely doubted.
An ordinary precladistic assumption, based on the failure to acknowledge the
no character is a priori immune to homoplasy.
Oddly, he says heterocoelous vertebrae cannot evolve
from opisthocoelous ones, though several enantiornithines have partial
heterocoely, as do some deinonychosaurs.
Which he doesn't know, not having enough English-language literature, I bet.
I can only quote Scrooge McDuck: "Money isn't everything! But without money
everything is nothing!"
Even stranger, he seems to think birds' single oviduct couldn't evolve
one of a theropod's two oviducts, but as far as I can tell amniotes
have two oviducts.
Kurochkin's cladogram is-
Anything but a cladogram, of course. :-)
Discussing Archaeopteryx, Kurochkin correctly notes most of its birdlike
characters have been found in other theropods, though many of his examples
are subtly flawed. For instance, he states one such character is "the
double-condyled quadrate (although it is single-condyled in Archaeopteryx
and Enantiornithes, while in Ornithurae it is double-condyled)." In
actuality, most coelurosaurs (including tyrannosaurids, caenagnathoids,
troodontids and Archaeopteryx) have a surface on the quadrate which
contacts the braincase. Most basal euornithines are similar, an in fact
the only taxa with a distinct double-condyled morphology are Shuvuuia,
Confuciusornis, Enaliornis and many neoavians.
Good to know.
(9) Digits IV and V of the manus are reduced. Only absent in
ornithuromorphs according to Kurochkin due to his disbelief in the
Assuming a frameshift is even necessary -- I'm still waiting for evidence
against the occurrence of a transient prepollex in bird embryos.
3. "the distal head of the femur has a lateral crest;" Absent in
Archaeopteryx (Chiappe, 2002).
Distal head? What does that mean?