Re: Ah ha! That's where therizinosaurs came from

[David Marjanovic <david.marjanovic@gmx.at>]

>  I was in the Hopkins library gathering material to restore the
>  skeleton of Johelornis now that there are enough skulls and skeletons
>  lying around when I did the proverbial dope slap as I realized the
>  probable ancestoral source for therizinosaurs.

Is there now a consensus that *Jeholornis* has priority over 
*Shenzhouraptor*?

And what's up with *Eshanosaurus*?
1) 
http://scienceblogs.com/tetrapodzoology/2007/02/therizinosauroids_and_altanger.php#comment-352331 
and downwards
2) Barrett, P. M. 2009. The affinities of the enigmatic dinosaur 
*Eshanosaurus deguchiianus* from the Early Jurassic of Yunnan Province, 
People's Republic of China. Palaeontology 52(4): 681 -- 688; 
http://dx.doi.org/10.1111/j.1475-4983.2009.00887.x

>  Now it all makes sense, phylonirvana has been achieved and what was
>  perplexing now is a lot more logical.

Making intuitive sense isn't all that important in science. Do you think 
quantum physics "makes sense"?

>  That cladistics does not at least currently support this is not
>  impoprtant because of the severely limited fossils on hand. After
>  all, had I been a cladist I never would have come up with the
>  neoflightless concept in the first place.

You would, just probably a couple of years later. Nowadays, with 
*Microraptor*, *Rahonavis*, *Anchiornis*, *Archaeopteryx* and the 
"suspicious" *Bambiraptor* and *Sinornithosaurus* on the 
deinonychosaurian side of things, the idea that the quill knobs of 
*Velociraptor* are retained from ancestors that engaged in some kind of 
aerial locomotion is at least as parsimonious as the alternative.

Indeed, just with *Microraptor* and *Rahonavis* alone, it was already 
equally parsimonious.

You claim to have a problem with cladistics. As far as I can see, you 
only haven't managed to put into words what your problem really is. 
After all, you don't reject Ockham's Razor! What's going on is that you 
think all flight-related characters are _correlated_ and should 
therefore be treated as a single character in phylogenetic analyses 
(perhaps as an ordered multistate character). That's entirely sensible, 
and you should publish this idea and test it. But if so, you should be 
consistent and treat herbivory-related characters as correlated, too.

Of course it's not trivial to figure out which characters are 
flight-related. Big sternum? Found in dromaeosaurids and oviraptorids, 
but *Sapeornis* preserves no trace of a sternum in two largely 
articulated skeletons, and *Archaeopteryx* only has a natural calcite 
cast of what must have been a wholly cartilaginous sternum in the Berlin 
specimen. <shrug> So perhaps it's size-related? Well, not in extant 
birds or even "*Liaoxiornis*".

>  And never mind that the
>  nonvolant ancestors of therizinosaurs and oviraptorosaurs remain
>  mysterious (probably because they never existed. Yes, yes, I know its
>  kind of silly but that's the scenario cladistics have been generating
>  so we must bow to the doctrine and think such silly things are
>  actually plausible. Or not.

The Early and Middle Jurassic are largely black boxes. They are gaps for 
us to stuff gods in. Let's stuff as few of them in as possible.