Re: Monster of Aramberri

[Adam S Smith <sea_saur@yahoo.co.uk>]

Hey guys, 
There may be a publication on the monster...
I've not tracked down a copy of this article yet, but
it looks promising. Sorry, I can't remember where I
got the reference from, nor be sure it is genuine:

Buchy, M.-C., Frey, E., Stinnesbeck, W., and
Lopez-Olivia, J. G., 2003, First occurrence of a
gigantic pliosaurid plesioaur from the Late Jurassic
(Kimmeridgian) of Mexico: Bulletin de la societie
geologiques de France, t. 174, n. 3, p. 271-278.

If anyone finds it, let me know!

Adam S. Smith, University of Bristol



 --- Colin McHenry <cmchenry@westserv.net.au> wrote: >

> 
> B B wrote:
> 
> > I have been trying to find out some details of a
> the Pliosaur 
> > (Liopleuodon?) from Mexico that has been named in
> the press as the 
> > Monster of Aramberri (forgive me if my spelling is
> off).  As it stands 
> > I have found a lot of nonspecific or contradictory
> facts.  Here is 
> > what I am wondering: 
> 
> Have you seen the entry on Richard Forrest's
> plesiosaur site?  
> http://www.plesiosaur.com/aramberri.htm  .  I would
> consider this to be 
> one of the more reliable sources on the web, in the
> absence of any 
> actual papers on the specimen.  There is a link to a
> pdf of a conference 
> abstract by Dino Frey et al., which appears to be
> the only published 
> account thus far.
> 
> >
> > 1.) How big is it? (I have read consistantly that
> the lower jaw was 10 
> > feet long, but the total length reports vary
> between 16 meters and 25 
> > meters) 
> 
> 
> They detail a pectoral vertebrae of 22 cm diameter,
> which (at a guess,) 
> puts it into the 13 - 16 metre range
> 
> >
> > 2.) How complete is it? 
> 
> not very
> 
> >
> > 3.) Has it been described?  If so where can I find
> a copy of the 
> > description? 
> 
> not yet
> 
> >
> > 4.) I heard that, "This specimen may require a
> re-evaluation of the 
> > size of other pliosaur specimens."  Does anyone
> know specifically what 
> > this statement refers to? (do they mean head to
> body ratio or some 
> > other system of body mass estimates?) 
> 
> I have no idea what that might mean
> 
> >
> > 5.) is it Liopleurodon sp, Liopleurodon Ferox,
> another pliosaur taxa 
> > entirely, or a new taxa?(I have read most often
> that it is 
> > Liopleurodon sp.) 
> 
> As Richard emphasises, it's unlikely to be
> Liopleurodon, which is 
> Callovian and according to Leslie Noe monotypic. 
> 
> >
> > 6.) Does this have anything to do the the huge
> Liopleurdon size given 
> > in Walking With Dinosaurs? 
> 
> No - that estimate was based upon;
> 1. A possibly incorrect re-identification of a large
> vertebra from the 
> Oxford Clay (Callovian) at the Peterborough Museum,
> previously 
> identified as a  'cetiosaurid' caudal, as a pliosaur
> cervical by 
> McHenry, Martill, Cruicksank, and Noe.  The vertebra
> is 24 cm across - 
> which, by comparison with Kronosaurus, gave us an
> estimate of  15 - 18 
> metres - _if_ it is pliosaurian...
> 
> 2. A really huge, robust mandibular symphysis from
> the Oxford Clay (in 
> the BMNH collection),
> 
> 3. The incorrect assignment of the Oxford mandibles
> (which are 
> 'Stretosaurus' macromerus, see below) to
> Liopleurodon.  The size 
> estimate of that animal is about 15 - 16 metres. 
> This lead to..
> 
> 4. Dave Martill is (or at least, has been in the
> past) quite comfortable 
> with 'upsizing' maximum size estimates - the logic
> being, if the 
> specimen you've got is X long, then given that it is
> unlikely that 
> you've got the biggest individual of that species,
> you can say that the 
> species grew to Y metres long.  It is not a practice
> I would agree with 
> unless it's late, the bar is full, and the Guinness
> is good (and it's 
> Dave's round).  Anyway, when he was consulting with
> WWD (and this is 
> according to Darren Naish) used a guess of 15 - 18
> metres (which he 
> based upon the three specimens listed above) and
> gave them a total 
> length for Liopleurodon of 25 metres.  There is,
> however, no evidence 
> for any pliosaur getting to this sort of size.
> 
> 5. The mass estimate of 150 tonnes was all Tim
> Haines' - apparently he 
> saw that blue whales are about that size (25 m is a
> small blue) and then 
> came up with the weight estimate based upon blue
> whales.  However, the 
> estimates for 150 tonne weights in blue whales is
> baed upon animals 
> larger than 30 metres long.  A 25 metre blue would
> be about 75 tonnes 
> (but there would a large range).  Given that
> pliosaurs are not as bulky 
> as a roqual, a theoretical 25 metre pliosaur would
> probably be around 50 
> tonnes.  But remember, there is abosutely zero
> fossil evidence for 
> pliosaurs getting that big.  The largest pliosaur
> based upon anything 
> like complete remains is Kronosaurus boyancensis,
> which is about the 10 
> metre mark (the tail's not preserved, so it's hard
> to be sure, but the 
> snout - hips length is approx 8 metres.)  Even if
> the various fragments 
> from the Middle and Upper Jurassic turn out to be
> pliosaurs, not of 
> these really suggest anything bigger than 15 - 16
> metres long.
> 
> >
> > 7.) Does anyone know what formation or age this
> specimen is from? (I 
> > know it is Late Jurassic, other than that I don't
> know anything more 
> > detailed) 
> 
> They give the stratigraphy as being the La Casita
> Fm, which is 
> apparently Kimmeridgian.  This takes it well outside
> the documented 
> range of Liopleurodon, and into the same age as some
> other biggies, such 
> as Pliosaurus brachyspondylus, 'Stretosaurus' (=
> Pliosaurus?) 
> macromerus, and Megalneusaurus rex.  The first of
> these is well 
> described, but is not believed to get any bigger
> than about 8-10 
> metres.  'Stretosaurus' macromerus is a taxon in
> need of revision that 
> has had a load of large Kimmeridgean bits and pieces
> assigned to it, 
> including Owen's 'Pliosaurus grandis' and the famous
> 3 metre Oxford 
> mandibles.  On the basis of the Oxford jaw, it may
> have reached 15 - 16 
> metres.  Megalneusaurus rex is still(?) under
> revision by Bob Bakker, 
> but is probably only slightly bigger than
> Kronosaurus (i.e. up to 12 
> metres) and may be the same thing as Stretosaurus. 
> I doubt there were 
> three genera of giant pliosaur in the Kimmeridgean,
> but you never know...
> 
> 
> This subject appears to have arisen periodically on
> this list and the 
> vrtpaleo list.  Check out the on-line artcile by Ben
> Creisler (I don't 
> have the url handy), and see the relavent chapter in
> Richard Ellis' 
> book.  Also (because the vrtplaeo list doesn't have
> archives), pasted 
> below is a post I made a couple of years ago.  Note
> Leslie's comments on 
> the Oxford jaws.   In the meantime, we look forward
> to a publication on 
> 
=== message truncated === 


        
        
                
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