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RE: New review paper of tyrannosaur paleobiology in Science, with new phylogeny



I would think this is more about Carr, not Brustatte, as it was Carr who 
produced the ontogenetic study that is being usd, and was a coauthor of the 
Alioramus paper. I think Mickey has previously commented about this (but don't 
hold me to that assumption).

  However, I think it is possible, if not likely, that some taxa can have 
ontogenetically "juvenile" features while still being adult (paedomorphism). 
When it comes to generally "juvenile" skeletal and proportionate features in 
otherwise fundamentally "adult" skeletons that exhibit various other "adult," 
proportional or ossification trends, one may be permitted the ability to assume 
or propose a slight paedomorphic trend. Note, for example, that *Xiongguanlong* 
has an enormously slender and elongate skull, large rounded orbit, and 
extremely elongate preorbital skull, and large skull relative to its body, but 
is nonetheless not apparently a juvenile. There should be no constraint that a 
juvenile morphology should suppress any and all conclusions toward a more 
mature status, especially given the meagre study so far produced for the taxa 
presented.

Cheers,

Jaime A. Headden
The Bite Stuff (site v2)
http://qilong.wordpress.com/

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


"Ever since man first left his cave and met a stranger with a
different language and a new way of looking at things, the human race
has had a dream: to kill him, so we don't have to learn his language or
his new way of looking at things." --- Zapp Brannigan (Beast With a Billion 
Backs)





----------------------------------------
> Date: Thu, 16 Sep 2010 18:35:38 +0000
> From: df9465@yahoo.co.uk
> To: dinosaur@usc.edu
> Subject: Re: New review paper of tyrannosaur paleobiology in Science, with 
> new phylogeny
>
> Can somebody explain to me the weird trend in Brusatte tyrannosaur articles
> where he ignores some of his own points about ontogeny.
>
>
> On the one hand, he states that tyrannosaurid skulls elongate through 
> ontogeny,
> teeth become more robust, yet on the other hand claims these same characters 
> are
> important features of Alioramus, which the authors acknowledge is based on a
> juvenile specimen and derives form the same deposits as Tarbosaurus. IIRC
> Alioramus is justified by the apparent elaborate skull ornamentation. However,
> skull ornamentation in dinosaurs can often be less pronounced/elaborate in
> adults (Horner & Goodwin, Triceratops). Brusatte cites this in the Alioramus
> description, but makes the opposite claim.
>
>
> ----------------------------------
> Denver Fowler
> df9465@yahoo.co.uk
> http://www.denverfowler.com
> -----------------------------------
>
>
>
> ----- Original Message ----
> From: "Thomas R. Holtz, Jr." 
> To: DML 
> Sent: Thu, 16 September, 2010 12:18:55
> Subject: New review paper of tyrannosaur paleobiology in Science, with new
> phylogeny
>
> http://www.sciencemag.org/cgi/content/full/329/5998/1481
>
> Brusatte, S.L., M.A. Norell, T.D. Carr, G.M. Erickson, J.R. Hutchinson, A.M.
> Balanoff, G.S. Bever, J.N. Choiniere, P.J. Makovicky, & X. Xu. 2010. Review:
> Tyrannosaur Paleobiology: New Research on Ancient Exemplar Organisms.
> Science 329: 1481-1485.
>
> Tyrannosaurs, the group of dinosaurian carnivores that includes
> Tyrannosaurus rex and its closest relatives, are icons of prehistory. They
> are also the most intensively studied extinct dinosaurs, and thanks to large
> sample sizes and an influx of new discoveries, have become ancient exemplar
> organisms used to study many themes in vertebrate paleontology. A phylogeny
> that includes recently described species shows that tyrannosaurs originated
> by the Middle Jurassic but remained mostly small and ecologically marginal
> until the latest Cretaceous. Anatomical, biomechanical, and histological
> studies of T. rex and other derived tyrannosaurs show t
> rapidly, were capable of crushing bite forces,
> had accelerated growth rates and keen senses, and underwent pronounced
> changes during ontogeny. The biology and evolutionary history of
> tyrannosaurs provide a foundation for comparison with other dinosaurs and
> living organisms.
>
> -----
>
> A review paper, not new research as such. But Brusatte & Carr have pooled
> their resources to produce a new phylogeny:
>
> Tyrannosauroidea
> |--Proceratosauridae
> | |--Kileskus
> | `--+--Proceratosaurus
> | `--+--Guanlong
> | `--Sinotyrannus
> `--+--Dilong
> `--+--+--Eotyrannus
> | `--Stokesosaurus
> `--+--Xiongguanlong
> `--+--Dryptosaurus
> `--+--Raptorex
> `--+--Appalachiosaurus
> `--+--Bistahieversor
> `--Tyrannosauridae
> |--Albertosaurinae
> | |--Albertosaurus
> | `--Gorgosaurus
> `--Tyrannosaurinae
> |--Alioramus
> `--+--Utah taxon
> `--+--Daspletosaurus
> `--+--Tarbosaurus
> `--Tyrannosaurus
>
> Congrats, folks!
>
> 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
>
>
>