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

[Denver Fowler <df9465@yahoo.co.uk>]

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." <tholtz@umd.edu>
To: DML <dinosaur@usc.edu>
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