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Re: A Request
Dan Varner wrote-
> This abstract appeared on the list nearly a month ago. So far I've
> no comments about the publication. Has anyone here read this yet and can
> offer any comments? Does this mean there's feather-plucking going on in
> Or not? DV.
So, you missed my numerous insults of that paper, did you? ;-) I included it
in my "Evolutionary Origin of Feathers volume" post back in January-
http://www.cmnh.org/fun/dinosaur-archive/2001Jan/msg00263.html . Here's the
part on that article specifically.
Martin and Czerkas, 2000. The fossil record of feather evolution in the
Saving the best for last. Pelecanimimus apparently now has pebble-like
scales. It must be news to Briggs et al. (1997) who found all purported
skin except a small bare patch on the throat pouch was actually internal
tissue. Sinosauropteryx also now has scale impressions preserved. At least
that's how Martin views the filament cross-sections. He claims feather
quills would be widely separated from each other, apparently disregarding
the fact these are more primitive than modern feathers and compressed
together. The authors claim Protarchaeopteryx could have limited flight
capabilities with long enough feathers. Bambiraptor's arms are longer, so
any such statement could be applied to it as well. Reasons it is a bird-
- teeth with waisted crown and expanded roots. Also in troodontids,
Archaeornithoides, Microraptor, alvarezsaurids (which Martin considers
ornithomimosaur relatives), etc.
- reduced serrations on teeth. Also in Pelecanimimus, Archaeornithoides,
Byronosaurus, alvarezsaurids, etc.
- shortened tail. It's not as short as Caudipteryx's, but rather close to
oviraptorids and Nomingia.
- shortened fibula. This is unknown (Ji et al., 1998), but mononykines,
Rahonavis and troodontids all share this feature anyway.
- reflexed hallux. Probably false, but present in Microraptor and Rahonavis
in any case.
Again, no evidence withstands scrutiny and their assignment of Rahonavis to
the Dinosauria helped (but was not neccessary for) my case.
Caudipteryx is a bird because:
- teeth with expanded roots. See above.
- primary feathers. See above under "veined feather structure".
- carpus with at least four bones. Actually, there are three, but more are
present in allosaurids, segnosaurs, tyrannosaurids and ornithomimids anyway.
- absence of pubic foot. Completely false (Zhou and Wang, 2000; Currie
pers. comm. 1999). Mononykines and troodontids have absent or highly
reduced pubic feet even if Martin and Czerkas were right.
- reflexed hallux. Probably true this time, but see above for undisputed
dinosaurs with it too.
- shortened tail. See above again.
It's more derived than Archaeopteryx based on:
- no maxillary or dentary teeth. Enantiornithines and ornithurines
primitively lack this. Is Caudipteryx supposed to be a carinate? Many
dinosaurs (ornithomimids, oviraptorosaurs) also have this.
- external mandibular fenestra present. Plesiomorphic and present in
virtually all theropods, while absent in a couple enantiornithines and maybe
- enlarged premaxilla. No more than oviraptorids.
- reduced maxilla. Correlated with the above character and also present in
- reduced hypopubic cup. Plesiomorphic and present in nearly all dinosaurs
- ball-shaped femoral head. Plesiomorphy only absent in Archaeopteryx and
- reduced fibula. False (Ji et al., 1998), but present in troodontids, etc.
- reduced calcaneum. Less reduced than troodontids :-)
- greatly shortened tail with evidence of pygostyle formation. See above.
There is also a hilarious skeletal reconstruction of Caudipteryx in an
upright posture. The ilium now has pointed preacetabular and postacetabular
processes, despite obviously being expanded anteriorly and squared-off
posteriorly. How can they get away with such fraudulent artistry? We learn
the obturator process is missing because the ischium was upside down the
whole time! ;-) It's actually the proximodorsal process, despite both being
preserved the other way in IVPP V 12344. Now I see why it's so ambiguous...
;-) Finally, the pubis has been trimmed to make it not pass the ischium in
its extreme opisthopubic orientation. Sigh.