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Re: The claws of hoatzin and the "Dinosaur renaissance" article



Just answering a few questions - I'll leave the others to the more expert:

On 26/11/04 9:11 am, "Vladimír  Socha" <Seismosaurus@seznam.cz> wrote:

> 1.) Who claimed for the first time, that birds are closely resembled with
> dinosaurs? Was it E. B. Hitchcock?
    Actually, I think Huxley suggested it way back in the 19th century.
Dinosaurs were actually originally imagined as quite active beasts when
first described by Owen and co. - it was only later that they became
regarded as more sluggish.


> 5.) Is _Protoavis texensis_ taken into account when considering the phylogeny
> of a feathered theropods?
    From what I've seen, no. The hypodigm of _Protoavis_ is contentious as
all out (and doesn't include feathers, by the way), having been found
scattered through a site, with some claims that it represents a chimaera of
drepanosaurid axial elements and basal theropod appendicular elements.
http://wiki.cotch.net/wiki.phtml?title=The_Protoavis_controversy gives a
good web review of the situation, with references.
    Even ignoring the possibility of a chimaera, there's not much to support
bird status. One of Chatterjee's papers on it includes a phylogenetic
analysis that seems to indicate that _Protoavis_ is closer to modern birds
than _Archaeopteryx_. However, a cursory glance shows that the tree includes
only a single outgroup, _Velociraptor_:
    0--Velociraptor
    `--+--Archaeopteryx
       `--+--Protoavis
          `--other birds
However, if _Protoavis_ is not a bird, it is almost certainly further from
birds than _Velociraptor_. Simply rerooting the tree on _Protoavis_ gives
the topology
    0--Protoavis
    `--+--+--Velociraptor
       |  `--Archaeopteryx
       `--other birds
Which, while heterodox, is not a completely unacceptable suggestion,
especially in light of the small number of taxa included in the analysis.


> 17.) Does any other non-avian genus except _Nomingia gobiensis_ displays a
> pygostyle?
There is at least one in the therizinosaur _Beipiaosaurus_:
Xu, X., Y.Cheng, X.Wang & C.Chang 2003 "Pygostyle-like Structure from
Beipiaosaurus (Theropoda, Therizinosauroidea) from the Lower Cretaceous
Yixian Formation of Liaoning, China". Acta Geologica Sinica 77(3):294-298.


    Cheers,

        Christopher