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Re: Fwd: the largest Pterosaur



Hi Mike,

To be honest, the remains of these giants are so scrappy that I feel
we're clutching at straws trying to guess their size and mass. I mean,
the Hatzegopteryx (finally spelt correctly - third time lucky) skull
appears to be relatively robust compared to that of Quetzalcoatlus, but
who knows if this reflects gross dimensions elsewhere? To me, the
humerus of Hatzegopteryx and Quetzalcoatlus look a bit different:
Hatzegopteryx has a relatively slender deltopectoral crest compared to
Quetzalcoatlus, but, conversely, appears to have a thicker diaphysis
(like yourself, these observations are based on photographs). Of course,
this situation is not aided in that the Hatzegopteryx is pretty beaten
up: I really think we need more material before any definitive
conclusions can be drawn.

Still, if Hatzegopteryx did have a greater wingspan, I reckon it
would've weighed more. Increased body size generally corresponds with
increased mass (though not in a linear relationship, of course) and,
with all the additional flight musculature needed to flap those
expansive wings, I think an azhdarchid with a 14 m wingspan would weigh
a lot more than an 11 m specimen. I think we sometimes forget with all
these measurements that something like a 3 m difference (to use the
example here) is actually quite a big distinction: the walls in the room
I'm sitting in now are about 3 m tall, which is a significant dimension.
It's all relative, of course: 3 m might mean a lot to comparisons
between 10 -14 m pterosaurs, but comparatively little to gigantic, 30 m
+ sauropods. All the same, even accounting for increased pneumatisation
and all that, I think it's hard to avoid a extra mass if your azhdarchid
has a wingspan one-storey broader than another (if that makes any
sense). 

Cheers,

Mark


>>> MICHAEL HABIB <habib@jhmi.edu> 23/04/2007 18:34 >>>
Very nice work, Mark.  The scale diagram really runs home how large the
animals were.  I wonder if Hatzegopteryx actually outweighed Q.
northropi, though.  The images of the Hatzegopteryx humerus do not
suggest to me an animal any more robust than Q. northropi, though I
admit to having only seen images and not the actually specimen.  The
wingspan may have indeed been larger, but that may not be a particularly
good correlate of mass in this case.  Any thoughts?

--Mike H.


----- Original Message -----
From: Mark Witton <Mark.Witton@port.ac.uk>
Date: Monday, April 23, 2007 11:28 am
Subject: Fwd: the largest Pterosaur
To: sakata-c@asahi.com, dinosaur@usc.edu 


> Hi there,
>  
>  The biggest pterosaurs are not known from complete specimens, so
all
>  the figures you see on this subject are only estimates based on
>  extrapolation from smaller, more complete finds. Currently, the
record
>  holders amongst pterosaurs (and, indeed, all volant animals) are
the
>  giant azhdarchids, enormous pterosaurs that existed across the world

> in
>  the Cretaceous. The best known of these is Quetzalcoatlus nothropi
from
>  the Javelina Formation of Texas. Known from a stupendously big
humerus
>  and other fragmentary elements, the wingspan of this animal is
estimated
>  at 10 - 11 m with a shoulder height of 2.5 m when it stood on the
>  ground. 
>  
>  However, other azhdarchids known from even scantier material hint
at
>  bigger animals. Arambourgiania philidelphae, a pterosaur known from
a
>  solitary neck vertebrae and scrappy wing elements from Jordan, may
have
>  achieved a wingspan of 11 - 13 m. However, Hatzagopteryx thambema is

> the
>  current record holder for the largest pterosaur known: with only a
few
>  pieces of skull and a couple of scrappy limb elements, estimates
for
>  this critter put it between 12 - 14 m across the wings.
>  
>  At the risk of blowing my own trumpet, you can see for yourself how
big
>  some of these pterosaurs got here:
>  
>  
>  
>  
>  And, for more pterosaur-y goodness (including pictures of
monstrously
>  big pterosaurs), check out the DML endorsed:
>  
>   
>  
>  Cheers, 
>  
>  Mark Witton
>  
>  --
>   
>  Mark Witton
>   
>  Palaeobiology Research Group
>  School of Earth and Environmental Sciences
>  University of Portsmouth
>  Burnaby Building
>  Burnaby Road
>  Portsmouth
>  PO1 3QL
>   
>  Tel: (44)2392 842418
>  E-mail: Mark.Witton@port.ac.uk 
>  
>  
>  >>> <sakata-c@asahi.com> 23/04/2007 12:07 >>>
>  Dear lists, 
>  
>  I would appreciate it if someone could tell me.
>  
>  What is the most largest Pterosaur?
>  
>  
>  Chisako SAKATA