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



Tim Williams wrote- 

> This may be well known, but it was news to me that _Bagaraatan_ is a
> chimera (based on specimens belonging to tyrannosauroids and other
> taxa).

It's only been mentioned as a possibility in Brusatte's thesis so far, not 
demonstrated with evidence.  As I write on the Database- "Finally, Brusatte 
(2013)  strongly suspects Bagaraatan is a chimaera of tyrannosauroid and other  
coelurosaurian elements, which will be the subject of a paper written by 
Makovicky,  himself and others. Based on general morphology and the above 
results, it may  end up that the mandible, vertebrae and pelvis are 
tyrannosauroid while the  hindlimb is troodontid."  Though it would be 
suspicious not to have any duplicated elements (unless they weren't mentioned 
by Osmolska).

Reference- Brusatte, 2013. The phylogeny of basal coelurosaurian theropods 
(Archosauria: 
  Dinosauria) and patterns of morphological evolution during the dinosaur-bird 
  transition. PhD thesis, Columbia University. 944 pp. 

> The Bayesian analysis recovers_Dryptosaurus_ as sister taxon to the
> _Alioramus_/_Qianzhousaurus_ clade (which Mickey would call
> _Alioramus_). I find this fascinating, that _Dryptosaurus_ is a North
> American alioramin (or if we want to get all technical re priority -
> that _Alioramus_ and _Qianzhousaurus_ are East Asian dryptosaurins).
> The same Bayesian analysis also has _Daspletosaurus_ as paraphyletic,
> which (if upheld) would justify assigning the new species to a
> separate (and new) genus.
>
> Conspicuous by their absence is any mention of putative Australian
> tyrannosauroids, including isolated pubic elements and the holotype
> femur of _Timimus_ (Benson et al., 2010, 2012). This is no surprise,
> given that both referrals have proven controversial.
>
>
> On Wed, Feb 3, 2016 at 8:56 PM, Mickey Mortimer
> <mickey_mortimer111@msn.com> wrote:
>> 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, beca
 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 h
> ad
>> 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=W
>>>
>>> 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.
>>