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RE: Phylogeny and evolutionary history of tyrannosauroid dinosaurs (free pdf)



Great analysis, but inaccurate use of the term "nomen dubium" crops up again- 
"We do not include the controversial taxon ‘Nanotyrannus lancensis’ in our 
dataset, because our previous work has argued that this taxon is a nomen 
dubium, as it is represented by material that belongs to juvenile Tyrannosaurus 
rex."  No, that makes it a junior synonym.  A nomen dubium is a taxon that is 
indeterminate, i.e. it cannot be distinguished from at least two other taxa 
(e.g. ICZN Article 75.5).

I have to congratulate Brusatte and Carr on including 58 pages of detailed 
discussion on why they excluded certain characters used in Loewen et al.'s 
tyrannosauroid analysis.  They also include characters from a "Carr and 
Varricchio in press", which is no doubt the description of the Two Medicine 
?Daspletosaurus species, so it's nice to see that's so close to publiaction.  
One thing that's odd is that the authors mention the Dueling Dinosaurs specimen 
of 'Nanotyrannus' as one that "may hold the key to solving this debate", but 
don't mention Jane at all.  Surely it would have been a good opportunity for 
Carr to say he's working on a monograph of it.  I wonder if Brusatte and Carr 
scored Raptorex as a juvenile, because its basal position suggests not.  
Finally, I wish people would just sink altai and Qianzhousaurus already.  
They're so similar to Alioramus remotus and at least Carr has implied on his 
blog that altai only made it as a separate species because other coauthors had
  power in that decision.

Mickey Mortimer

----------------------------------------
> Date: Tue, 2 Feb 2016 07:46:49 -0800
> From: bcreisler@gmail.com
> To: dinosaur@usc.edu
> Subject: Phylogeny and evolutionary history of tyrannosauroid dinosaurs (free 
> pdf)
>
> Ben Creisler
> bcreisler@gmail.com
>
> A new paper in open access:
>
> Stephen L. Brusatte & Thomas D. Carr (2016)
> The phylogeny and evolutionary history of tyrannosauroid dinosaurs.
> Scientific Reports 6, Article number: 20252 (2016)
> doi:10.1038/srep20252
> https://urldefense.proofpoint.com/v2/url?u=http-3A__www.nature.com_articles_srep20252&d=CwIF-g&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=x82f3Wlkwtmbr1z8IAt9jA&m=8CS9pjkx3qV5CBLXTxRz9YaE6MYtepqCqNgBnjBu3tI&s=WOCZPY1s09-nD9bF8lCSpJKyyPc5GIH4VP3VPsitjJU&e=
>  
>
> Tyrannosauroids—the group of carnivores including Tyrannosaurs rex—are
> some of the most familiar dinosaurs of all. A surge of recent
> discoveries has helped clarify some aspects of their evolution, but
> competing phylogenetic hypotheses raise questions about their
> relationships, biogeography, and fossil record quality. We present a
> new phylogenetic dataset, which merges published datasets and
> incorporates recently discovered taxa. We analyze it with parsimony
> and, for the first time for a tyrannosauroid dataset, Bayesian
> techniques. The parsimony and Bayesian results are highly congruent,
> and provide a framework for interpreting the biogeography and
> evolutionary history of tyrannosauroids. Our phylogenies illustrate
> that the body plan of the colossal species evolved piecemeal, imply no
> clear division between northern and southern species in western North
> America as had been argued, and suggest that T. rex may have been an
> Asian migrant to North America. Over-reliance on cranial shape
> characters may explain why published parsimony studies have diverged
> and filling three major gaps in the fossil record holds the most
> promise for future work.