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Re: Rant (was RE: Details on SVP 2002 Part 2)



I've been too busy these past two weeks to reply to Tom's email in the detail 
that I think is required. Here goes nothing.

In a message dated 10/16/02 8:07:26 AM EST, tholtz@geol.umd.edu writes:

<< Okay, folks have been telling me all meeting about how I don't blow my cool
 when dealing with posts on the list.  Folks, please note the time: I am now
 blowing my cool on this list.  I am doing so here because unlike several
 recent cases of newbies, George has been around long enough to know better.>>

Stop patronizing me, Tom. You know where I'm at with cladistics.
 
<< George, you have NEVER SEEN the three new taxa: how can you *POSSIBLY* 
have an informed opinion on them?>>

The specimens as far as I know have all been decently described in the 
literature, plus I've actually seen and handled the New Mex material. How can 
you possibly say I've NEVER SEEN the three new taxa when you don't know what 
I've been doing and whom I've been in correspondence with?
 
<< Carr has logged as many hours on tyrannosaurid specimens as just about
 anyone alive: not pictures, not drawings, not casts, but *specimens*.>>

I don't question Carr's scholarship for a minute, and I can't wait to see his 
paper.
 
<< Given that Currie, and me, and Carr, and Brochu, and Carpenter, and Paul
 *ALL* agree based on direct observations of specimens that Tarbosaurus and
 Tyrannosaurus are closer to each other than they are to other tyrannosaurid
 taxa (except perhaps for Daspletosaurus, which may or may not be within the
 node joining these two), doesn't that give you some clue that PERHAPS this
 analysis was done correctly?>>

Could be groupthink. I, too, have examined a number of rex skulls as well as 
the holotype bataar skull, specimens (when they're been on tour and passed 
through LA, for example) not just casts and drawings, which are in some cases 
rather misleading because they lack the third dimension--and I have come up 
with a different conclusion. Vive la difference.
 
<< Yes, they are different animals.  Duh.  Yes, they have different tooth
 counts.  Duh.  No one has synonymized rex and bataar yet; they merely
 recognize that rex and bataar are most likely closer to each other than they
 are to the albertosaur-grade forms.>>

I say bataar is closer to the albertosaurs than to rex, on the basis of the 
shape of the skull, the position and direction of the orbits, the position 
and direction of the occipital condyle. I say the reason for this is 
plesiomorphy, not synapomorphy. Bataar and rex are end nodes of two distinct 
lineages of tyrannosaurid, one Mongolian and one North American, so they 
can't be in the same genus. Any similarities between rex and bataar can be 
chalked up to convergence.
 
<< No one says one can score 149 characters *from Dryptosaurus*.  That you 
seem
 to think they could suggests to me that after all these years you still have
 yet to try to learn the technique, how it deals with missing data, etc.>>

What good are 149 characters if 95 of them are question marks? It's unfair to 
promote a phylogenetic analysis this way. Suppose more material resolves the 
question marks and most of them go the wrong way?  Minor characters such as 
the position of a condyle or the location of a foramen could be extremely 
labile and thus virtually useless for phylogeny.
 
<< There is vastly more material for Dryptosaurus than there is for fairy tale
 tree-dwelling ancestors for every major branch of Dinosauria.>>

Stop calling BCF a fairy tale. It remains the most parsimonious theory for 
the evolution of dinosaurs, even if I haven't had the time to write it all up 
yet.

<<  That Dryptosaurus does share a handful (three or four) characters 
uniquely with
 classic tyrannosaurids which are not observed in other theropods is now
 documented by Carr (although Currie and I also made similar, although not
 the same particular, observations).  Is it definitely a tyrannosauroid:
 surely not.  Is it most likely a tyrannosauroid based on current
 information: that is what the analyses are saying.>>

Well, for a long time Horner & Baird held the idea that Drypto was a 
tyrannosaurid, perhaps based on those characters (don't recall for sure), but 
after a while they dropped the idea. I'm not averse to considering Drypto a 
tyrannosaurian of some kind, but would like to see this better documented.
 
<< Coda the First: Lest people think otherwise, I do not "dogmatically" accept
 Carr's phylogeny.   I think he might well be correct, but I haven't seen the
 full detailed version (esp. with regards to the New Mexico and Utah taxa).
 What I have seen, though, shows that it is a major scientific work.  Yes,
 the results differ somewhat from my own, and from the work of others, but
 that is okay.>>

Like I said, can't wait for the paper.
 
<< Coda the Second: Lest people think otherwise, I actually think George has a
 lot of good ideas and observations.  I am merely (over?) reacting to his
 response to a description of research which he did not see.  George has been
 aware of dinosaur research for a long time now, and has added important
 taxonomic contributions.  However, BECAUSE he has been aware of the work for
 this long, he should know better by now that one should wait and see the
 specimens (heck, even a figure in this case) before making judgement.>>

For one thing, I don't see a heck of a lot of difference between 
Daspletosaurus torosus and Albertosaurus sarcophagus, certainly not enough 
for a generic distinction. Daspletosaurus should be sunk as a distinct 
species of Albertosaurus, namely, Albertosaurus torosus. If you want to see 
generic distinction, consider that Iguanodon bernissartensis and Iguanodon 
atherfieldensis have been classified in the genus Iguanodon for 
three-quarters of a century, and they're >certainly< generically different.
 
<< (And if you are going to play the gross morphology game, then the Utah 
taxon
 would make a better new Daspletosaurus than an Albertosaurus!). >>

See comment above.