From: swf@teradata.com (Stanley Friesen)
Newsgroups: talk.origins
Subject: Re: Holden and superhumongoreallybigosaur weights
Date: 18 Aug 92 20:28:46 GMT
Reply-To: swf@tdat.teradata.com (Stanley Friesen)
Organization: NCR Teradata Database Business Unit

In article <714065227@sheol.UUCP> throopw@sheol.UUCP (Wayne Throop) writes:
|> From: news@fedfil.UUCP (news) (Ted Holden)
|> Message-ID: <2863@fedfil.UUCP>
|> Artists conceptions of the seismosaur do not show him as a diplodocid.
|> I suspect the jury is still out on that one.
|
|Ted, of course, suspects wrongly.  I've already quoted at least one
|expert on the subject (namely Dr. David Gillette of the Division of
|State History in Utah).  The seismosaur is a diplodocid. 

Quite. There is no remaining doubt.
It was *thought* to be a brachiosaurid for a year or two back when only
a few limb bones had been excavated.  But when they got the backbone out
it was shown to be a diplodocid.  (The most characteristic parts of a
sauropod are the backbone and skull - they all have rather similar legs,
so limb bones are of little value in proper identification).

|  Gillette estimates the weight at 50
|tons, perhaps more, by volumetric methods.  (My own guess was 75 tons,
|but Gilette has more detailed size data, so we may probably safely go
|with his lower figure).

Again, this is not unreasonable for an elongate, mostly neck & tail,
diplodicid.  I would probably have guessed around 75 tons myself, but
like you, I do not have access to the latest measurements.

| In the '92 edition, they give figures for the Ultrasaur up to
|200 tons or so, and in the '91 edition gave a figure of 140 tons.  This
|is by NO means "only up to about a quarter" of McGowan's figure.  True,
|they end up settling on estimates are a bit lower than those of Colbert
|from 1962 (the ones McGowan refered to for his estimates), but Colbert's
|brachiosaurus estimates were among the highest, NOT (as Ted claims)
|representative of "what appears in most of the rest of the literature".

Aha!  I *thought* McGowan's numbers sounded high!   Colbert's 1962 estimates
where amoung the *first* modern estimates (based on volumetric methods).

More recent work has shown that he was consistantly *too* *high* in his
estimates.  This was because he used some very crude, imprecise
reconstructions for his volume measurements.  (I believe I remember that
he used those little plastic museum models everyone was buying in the
1960's - anyway he used consistantly fat reconstructions).

Ted, you really need to get some recent weight estimates for dinosaurs.
They are *always* lower than Colbert's.

|So, I conclude that breviparopus is a diplodocid, and that Guiness never
|intended to claim anything else.  Certainly the original reason I
|thought the breviparopus was a diplodocid was it's prominent mention in
|the diplodocid section of the '91 edition, and I see no sufficient
|reason to conclude otherwise now.  
|
|Of course, this is somewhat conjectural for my taste...  perhaps
|somebody can find the original papers on breviparopus to confirm or
|confound my interpretation, but until then, the weight/mass ratio of
|breviparopus, whether brachiosaurid (or more likely) diplodocid, is just
|a wild-eyed guess, and so doesn't do much to support Ted's case. 

I'm not sure, but this may be one of the rather less well known forms,
so its proper position may be indeterminate (along woth its weight).
|
|Another reason is that I just hate to see such fundamentally mistaken
|claims as Ted makes about sauropods go uncorrected.  Brachiosaurids and
|diplodocids are about as different as two species can be and still be
|sauropods.  Ted is buttressing his position by making obviously
|erronious claims, and pointing these errors out is hardly a "quibble".

They are about the dinosaur equivalents (in way of analogy) of Mastiffs
and Dachsunds.  (Diplodocids being rather like Dachsunds in shape).


-- 
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  or
Stanley.Friesen@ElSegundoCA.ncr.com