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Ah ha! That's where therizinosaurs came from



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. 

I have long been pointing out that all flightless "theropods" with 
extensive flight adaptations are likely to be secondarily flightless because no 
one 
has come up with really satisfactory arguments for why and how those flight 
characters evolved outside the context of flight, because early fliers 
should have been spinning off neoflightless descendents that retain flight 
characters, and the situation parallels that of ratites etc. 

It now looks pretty good is that as I pointed out back when Ronnie was Prez 
that predaceous Late Jurassic archaeopterygids some of which had fully 
developed wings were the ancestoral type if not group for more derived 
Cretaceous deinonychosaurs some of which had even better flight capabilities, 
and 
others being secondarily flightless. 

At the same time I was pointing out, and Osmolska too, that oviraptorosaurs 
were probably more avian than archaeopterygids and secondarily flightless. 
In the Field Guide I noted that the ancestoral group or type is likely to be 
your herbivorous omnivoropterygids. 

What has become most vexing is those pesky therizinosaurs. Some have those 
very long tails. So what basal flying theropods were herbivores with long 
tails? Well duh, jeholornithids. Not that jeholornirds specifically are 
prototherizinosaurs, they lack sufficient teeth for one thing. Now, other 
therizinosaurs have shorter tails. It is unlikely for that to be adaptative 
among 
evolving land herbivores that should retain long tails to counter balance the 
exapnding belly. It is therefore possible that what we call therizinosaurs 
descended from fliers more than once, with later therizinosaurs spinning off 
shorter tailed fliers. 

In this tentative scenario predaceous long tailed deinonychosaurs are the 
least derived, herbivorous long tailed projeholornithids/therizinosaurs more 
derived, and herbivorous short tailed omnivoropterygids/oviraptorosaurs the 
most derived. Deinonychosaurs may be on the avain line or a side branch. 

Now it all makes sense, phylonirvana has been achieved and what was 
perplexing now is a lot more logical. Blessed thanks be to the deities that 
probably do not exist. Could be wrong of course, but I suspect that future 
fossils 
that are the only means of testing the hypothesis will bear out the basic 
idea, although we may never know due to lack of sufficient transitional taxa. 

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. 

What the cladistics would have us believe is that all these predatory, 
omnivorous and herbivorous early fliers were flitting about in the later half 
of 
the Mesozoic yet for some magical reason were never spinning off 
reflightless forms that show up in the fossil record. Really, that's what the 
cladograms want us to take seriously. But not only that, a bunch of theropods 
that 
never had flying ancestors for some mysterious reasons happened to evolve not 
only feeding adaptations, heads and bodies eerily like those of the fliers, 
but also flight adaptations even though there is no good explanation why 
that would have happened. 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. 

If anyone else came up with the therizinosaurs are neoflightless 
jeholornids please let me know. 

And to think that anyone used to think that therizinosaurs were 
transitional to prosauropods-ornithischians! What a nincompoop, what a maroon. 

As for the Jeholornis skeletons its way cool, kind of a cross between 
Archaeopteryx and Falcarious (it's much less Archy like than some past 
restorations, arms much more massive). The absence of an accurate restoration 
may be 
one reason why the possible relationship to therizinosaurs was not picked up 
earlier. 

GSPaul</HTML>