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> Okay, now *I'm* curious...what exactly was the problem with
> _Therizinosaurus_...? Admittedly, I'm a rank amateur in this field, so
> new information is constantly flying past me with nary a glimpse.
At the risk of re-opening the never-ending debate over the placement of these
particular dinosaurs in respective phylogenies, _Therizinosaurus_ has been
reconstructed as a short-tailed, bipedal theropod by Russell and Russell. Thing
is, _Therizinosaurus_ is only really known from forelimbs, and to arrive at this
reconstruction they merely extrapolated from what is known of the earlier (and
assumed ancestral) form _Alxasaurus_.
As Peter has now pointed out on this list (too damn controversial for me!), the
restored _Alxasaurus_ described by Russell and Dong is perhaps not totally
accurate in the first place. Furthermore, to assume that a true descendant
organism will look like a hypothetical extrapolation based on an ancestor is a
process with difficulties and uncertainties inherent. Without using extreme
examples (e.g. extant cetaceans from protocetids, derived seals from early
arctoids), could you take, say, an early ornithopod and work out that its
descendant would look like a hadrosaur? Or the earliest felids, and make out
that _Smilodon_ or _Acinonyx_ would evolve from them? I would argue that this
is unknowable as, even though theoretically possible, there's no reason why it
should be so... bats haven't evolved gliding giants or flightless bipeds (except
in D. Dixon's head!), no arboreal frogs eat nestling birds full-time (I say
again, _full-time_), kangaroos have never become markedly long-necked and so on
To (attempt to) conclude then, the Russell and Russell hypothesised
_Therizinosaurus_ could well represent the possible life appearance of the
animal. Equally likely, of course, it could not. My personal belief is that
their reconstruction is on the right track, but I still say you can't assume
that evolution would work in such a simplistic fashion. Blind watchmaker,
constraints of human imagination, stranger than fiction and all that...
This little text could serve well as an update to my review (in the DCC
newsletter) of the Safari _Therizinosaurus_ sculpted by Ely Kish. When I wrote
that, I wasn't aware of R & R's new _Therizinosaurus_ reconstruction, and I owe
one to Tracy for sending me the literature and finding out for myself. TRACY
FORD IS THE MOST USEFUL PERSON ALIVE!! Thought I should thank him in public..
The Bakker fighting _Apatosaurus_ are _excelsus_, not _ajax_ as I said
previously. And Olson is spelt Olson, not Olsen. Whoops-a-daisy.
Special quote for Tim Isles (and feel free to discuss the broader framework in
which this quote is applicable -;): "So what are you thinking" "I'm thinking
we're out of a job" "Don't you mean extinct?".
But that's crap, so here's a real one:
"God kills indiscriminately, and so shall we"
DARREN 'where's my stash' NAISH