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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
I have long been pointing out that all flightless "theropods" with
extensive flight adaptations are likely to be secondarily flightless because no
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,
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
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
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
What the cladistics would have us believe is that all these predatory,
omnivorous and herbivorous early fliers were flitting about in the later half
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
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
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
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
one reason why the possible relationship to therizinosaurs was not picked up