[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: Gauthier and de Queiroz's Classification of Birds
T. Mike Keesey wrote-
> I just received my copy of _New Perspectives on the Origin and Early
> Evolution of Birds: Proceedings of the International Symposium in Honor of
> John H. Ostrom_. Absolutely fantastic volume.
I finally ordered mine, but have yet to recieve it.
> _Panaves_ (new clade name) = Clade(_Vultur gryphus_ <-- _Crocodylus
Isn't this clade already Ornithosuchia and Avemetatarsalia? I understand
the first is bad because it's non-eponymous, but the latter seems fine.
BTW- Ornithotarsi seems to be Gauthier's 1986 term for pterosaurs +
dinosaurs excluding Lagosuchus and such. So it wouldn't be the stem clade
of birds versus crocodilians, but rather something akin to Ornithodira.
> _Avifilopluma_ (new clade name) = Clade("feathers" in _Vultur gryphus_)
> ("'Feathers' refers to hollow-based, filamentous, epidermal appendages
> produced by follicles." Most other apomorphies used here are also
> explained further.)
Well, we'll (probably) never be able to demonstrate if fossilized epidermal
structures were produced by follicles. This is a _horrible_ clade in my
opinion. First, it's based on a feature only rarely preserved in fossil
taxa. Second, we don't know where exactly "feathers" first evolved in
dinosaurs. Did small non-coelurosaurs have "feathers"? How about small
ornithischians? The structures on Psittacosaurus certainly look filamentous
to me. If they're hollow, Avifilopluma is a junior synonym of Dinosauria.
And what about pterosaur "fur"? Isn't that also made of hollow filamentous
epidermal appendages? So Avifilopluma is a synonym of
Ornithodira/Ornithotarsi. Even ignoring Psittacosaurus and pterosaurs, how
does Avifilopluma relate to Coelurosauria? Minimally, they're both right
around the same area on the cladogram, but basal coelurosaur systematics are
so uncertain now, Sinosauropteryx + Neornithes is a useless clade.
> _Avialae_ = Clade("feathered wings used for powered flight" in _Vultur
Uh, yeah. So, (assuming the "feathers" simply being on the wings of
pterosaurs don't count, and the feathers must provide the main lift) that's
minimally something like Archaeopteryx + Neornithes, or Rahonavis +
Neornithes. So that's Aves, or a clade that's somewhere directly above or
below Aves. Of course, Greg Paul has some good points regarding secondary
flightlessness that could make all maniraptorans "avialans". And if George
is right, all dinosaurs are "avialans". Sorry, this is better as "all
closer to Neornithes than to Deinonychus".
> _Carinatae_ = Clade("keeled sternum" in _Vultur gryphus_)
Again, I'll ignore pterosaurs. Presumedly organisms that are so many
"phylogenetic distance units" away don't count towards apomorphy-based
definitions anymore. So, dinosaurian examples would be Mononykus and
Sinraptor. But no, wait, those aren't traditional carinates at all. And
Confuciusornis and Ingenia with their slight ridge, is that a keel? Of
course, there are tons of taxa between Sinraptor and Neornithes without
keels, but that doesn't matter. Looks like Carinatae sensu Gauthier and de
Queiroz is a junior synonym of both Avetheropoda and Neotetanurae
(Allosaurus + Neornithes). Let's leave it as Ichthyornis + Neornithes,
> _Ornithurae = Clade("tail with pygostyle shorter than femur" in _Vultur
Confuciusornis barely doesn't make it. Iberomesornis doesn't, nor does
Cathayornis? caudatus. But Sinornis does, and the more basal Jibeinia.
Liaoxiornis doesn't. Anyone else see a problem here? "Tail with pygostyle
shorter than femur" isn't a good character it all. I like Ornithurae as
Hesperornis + Neornithes.
> _Aves_ = Clade(_Struthio camelus_ + _Tetrao [Tinamus] major_ + _Vultur
Damn you crown group Aves. I'd thought we finished you off.