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RE: Spinosaurus proportions/limbsize/exploding head quotient



There is, as THE man for skeletal drawings points out, something fishy about 
the reconstruction: the pelvis and hind limbs are too small. By quite a bit - 
at least if you prefer to believe in the published bone measurements rather 
than in the reconstruction fiugre:

http://www.skeletaldrawing.com/home/theres-something-fishy-about-spinosaurus9112014

Why am I not surprised? Because the published figure is just too ridiculous.
Personally, I also have doubts about the identification of the caudal 
positions. The moment you shift them further back you can add anterior caudals 
with bigger spines, which may mean more mass in the tail base, which again 
shifts the center of mass backward.

Spinosaurus - not quite as weird as Figure S3 of Ibrahim et al. 2014 makes you 
believe.


Dr. Heinrich Mallison
Museum für Naturkunde - Leibniz Institute
for Evolution and Biodiversity Science
Invalidenstrasse 43
10115 Berlin
Germany
office: +49 (0)30 2093 8975
cell: +49 (0)179 5429922
email: heinrich.mallison@gmail.com, heinrich.mallison@mfn-berlin.de
blog: dinosaurpalaeo.wordpress.com

________________________________________
From: owner-DINOSAUR@usc.edu [owner-DINOSAUR@usc.edu] on behalf of Thomas R. 
Holtz, Jr. [tholtz@umd.edu]
Sent: Friday, September 12, 2014 1:33 PM
To: bucketfoot-al@justice.com; DINOSAUR@usc.edu
Subject: RE: Spinosaurus proportions/limbsize/exploding head quotient

Some notes:

17 m goes way beyond what they extrapolate. They suggest that the larger known 
specimens indicate a 15 m length.

We have zero evidence of sexual dimorphism in sail size, so any conclusions 
based on variations of these are mere speculation. Could be correct, could be 
totally wrong. Need fossils to say something more definite. For that matter, 
there is zero evidence of gregariousness in spinosaurids, so we can't assume 
group-related behaviors in taxa we don't know lived in groups.

The legs do belong to the new vertebral material, so those proportions are 
correct. The arms? That is a different story. If you read the Supporting Online 
Materia
nd separately, from different individuals, and not in articulation (obviously). 
So we don't know if the within-arm proportions are correct, or if the arms were 
truly so huge on the individual shown.

Sarcosuchus (the croc you mention) was discovered and named by French 
paleontologists in the 1960s; Sereno's discovery was a new, more complete 
specimen.

Thomas R. Holtz, Jr.
Email: tholtz@umd.edu   Phone: 301-405-4084
Office: Centreville 1216
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
http://www.geol.umd.edu/~tholtz/
Fax: 301-314-9661

Faculty Director, Science & Global Change Program, College Park Scholars
http://www.geol.umd.edu/sgc
Fax: 301-314-9843

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
                        Building 237, Room 1117
                        University of Maryland
                        College Park, MD 20742 USA
> -----Original Message-----
> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] On Behalf Of 
> Vlad Petnicki
> Sent: Friday, September 12, 2014 6:17 AM
> To: DINOSAUR@usc.edu
> Subject: Spinosaurus proportions/limbsize/exploding head quotient
>
> Well, I imagine that the classic scene from the sci fi movie "Scanners" has 
> been repeated several hundred, heck, million-fold today!
>
> Spinosaurus, one of the truly weird dinosaurs to begin with, turns out to be 
> perhaps THE most bizarre dino discovered to date!
>
> Essentially it looks like a 17-meter long torpedo with arms, legs and that 
> humongous sail.
>
> Before anyone else claims it, what do the pros out there think of my 
> observation that one of the uses of that sail may have beento
> help the animals identify the "Alpha Male" while they were all submerged in 
> the water, in order to keep everybody in line?  (I guess
> that falls into the "display" category vis-a-vis the purpose of the sail).
>
> What is more fascinating to me is the possibility that the sail also added 
> extra ballast - indeed, its shorter-sailed relatives did not have
> th
work - the more aquatic, the bigger the sail?)
>
> Lots of folks are properly cautious about making sure this new skeletal 
> reconstruction didn't make the mistake of pairing the legs of a
> smaller animal with the body of a fully grown adult - I am assuming here that 
> someone with Sereno's background would make
> quadruple-sure that there was no evidence of a mass-burial at the excavation 
> site.
>
> Sereno sure has carved his niche out, hasn't he?  Finder of Suchomimus, the 
> giant croc whose name escapes me, and now
> collaborating on "solving" the 100-year old mystery of Spinosaurus - this was 
> really a joint effort, starting with Stromer and then
> involving the Italians, Ibrahim, and Sereno.
>
> I hope its all backed up and airtight.
>
> Tom Holtz is right - this is a "nuclear bomb" going off in the middle of the 
> dino-phile community!!!!
>
> Awesome stuff!!
>
> --- DINOSAUR@usc.edu wrote:
>
> From: DINOSAUR@usc.edu
> To: Dinosaur Discussion List  <DINOSAUR@usc.edu>
> Subject: DINOSAUR digest 1677
> Date: Fri, 12 Sep 2014 00:04:08 PDT
>
>
>                           DINOSAUR Digest 1677
>
> Topics covered in this issue include:
>
>   1) Ikrandraco, new crested pterosaur from Early Cretaceous of China  (free 
> pdf)
>       by Ben Creisler <bcreisler@gmail.com>
>   2) Dinosaur tracksites from Lower Jurassic of Languedoc-Roussillon, France.
>       by Ben Creisler <bcreisler@gmail.com>
>   3) Re: Dinosaur tracksites from Lower Jurassic of Languedoc-Roussillon, 
> France.
>       by Ben Creisler <bcreisler@gmail.com>
>   4) Spinosaurus countdown begins...
>       by Ben Creisler <bcreisler@gmail.com>
>   5) RE: Spinosaurus countdown begins...
>       by "Thomas R. Holtz, Jr." <tholtz@umd.edu>
>   6) Re: Spinosaurus countdown begins...
>       by Ben Creisler <bcreisler@gmail.com>
>   7) RE: Spinosaurus countdown begins...
>       by "Thomas R. Holtz, Jr." <tholtz@umd.edu>
>   8) Spinosaurus redescribed as giant semiaquatic theropod
>       by Ben Creisler <bcreisler@gmail.com>
>   9) Re: Spinosaurus redescribed as giant semi
>       by Ben Creisler <bcreisler@gmail.com>
>  10) Re: Spinosaurus countdown begins...
>       by Luis Rey <luisrey@ndirect.co.uk>
>  11) Re: Spinosaurus redescribed as giant semiaquatic theropod
>       by Dann Pigdon <dannj@alphalink.com.au>
>  12) Re: Spinosaurus redescribed as giant semiaquatic theropod
>       by Ben Creisler <bcreisler@gmail.com>
>
>
>
>
> _____________________________________________________________
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