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Re: Nanotyrannus valid as member of Albertosaurinae, based on dentary groove



A blog comment:

http://tyrannosauroideacentral.blogspot.com/2016/01/by-way-that-groove-is-also-seen-in.html

On Thu, Jan 14, 2016 at 12:05 PM, Ben Creisler <bcreisler@gmail.com> wrote:
> Copy-paste problem (blame Windows). Here's the citation with the doi:
>
> Joshua D. Schmerge & Bruce M. Rothschild (2016)
> Distribution of the dentary groove of theropod dinosaurs: Implications
> for theropod phylogeny and the validity of the genus Nanotyrannus
> Bakker et al., 1988.
> Cretaceous Research 61: 26-33
> doi:10.1016/j.cretres.2015.12.016
> http://www.sciencedirect.com/science/article/pii/S0195667115301415
>
> On Thu, Jan 14, 2016 at 12:03 PM, Ben Creisler <bcreisler@gmail.com> wrote:
>> Ben Creisler
>> bcreisler@gmail.com
>>
>> A new paper:
>>
>> Joshua D. Schmerge & Bruce M. Rothschild (2016)
>> Distribution of the dentary groove of theropod dinosaurs: Implications
>> for theropod phylogeny and the validity of the genus Nanotyrannus
>> Bakker et al., 1988.
>> Cretaceous Research 61: 26-33
>> Joshua D. Schmerge & Bruce M. Rothschild (2016)
>> http://www.sciencedirect.com/science/article/pii/S0195667115301415
>>
>>
>>
>> This study examines the phylogenetic distribution of a morphologic
>> character, described as a groove containing pores, on the lateral
>> surface of the dentary bone in theropod dinosaurs. The nature of this
>> groove is a feature unique to theropods. Of the 92 theropod taxa
>> examined for the presence and absence of this feature, 48 possessed
>> and 44 lacked this feature. Distribution of this character was
>> compared to published phylogenetic analyses of theropods, in order to
>> evaluate the utility of the dentary groove as a diagnostic feature.
>> 80% of pre-Tyrannoraptoran theropods possessed the dentary groove,
>> with only 6 reversals in basal theropod clades. Theropods with beaks
>> or edentulous jaws all lacked a dentary groove. Tyrannosauroidea is
>> marked by mosaic distribution of this character. Among
>> tyrannosauroids, the dentary groove occurs only in Dryptosaurus and
>> the Albertosaurinae (Albertosaurus + Gorgosaurus). Nanotyrannus
>> lancensis, sometimes described as representing juvenile Tyrannosaurus
>> rex, also possesses this groove, unlike the remainder of the
>> Tyrannosaurinae. Nanotyrannus lancensis was included in a phylogenetic
>> analysis of Tyrannosauroidea and was recovered within Albertosaurinae.
>> We recommend that Nanotyrannus stand as a valid taxon nested within
>> the Albertosaurinae, based on the presence of this groove, as well as
>> other features of the skull.