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Re: [dinosaur] Latenivenatrix, new troodontid from Dinosaur Park Formation, Alberta (validity of Troodon)



One correction, though:

"That's why ... Titanosauridae are here to stay."

Actually, arguably not. Within Titanosauria there are several proposed and employed "families" (Saltasauridae, Nemegtosauridae, Aeolosauridae, potentially others). It is not at all certain which of these the Titanosaurus indicus material would belong to. If we agreed to put all of these in one family, that would be Titanosauridae. But if we regard them as distinct taxa, and cannot affirm where Titanosaurus goes, we can continue to not use "Titanosauridae".

On Fri, Aug 11, 2017 at 12:21 PM, David Marjanovic <david.marjanovic@gmx.at> wrote:
> I'd go one step further and abandon the name Troodontidae as well -
> and revert to using Saurornithoididae as the name for this clade. I
> know it's permissible to retain family-level taxa founded on nomina
> dubia (we still use Ceratopsidae, after all). But I still don't think
> it's a good idea (I also think the name Ceratopsidae should be
> abandoned).

It's not "permissible", it's required unless the family name is itself a nomen dubium, which is not automatically the case.

It's not like you get any choice in this matter as long as you stick to the ICZN. As long as the holotype tooth of *Troodon* fits the diagnosis of whatever "family" *Saurornithoides* belongs to and not that of any other "family", the name Troodontidae is valid and and Saurornithoididae is one of its junior synonyms. That's why Ceratopsidae and, yes, Titanosauridae are here to stay.

> As a nomen dubium, _Troodon_ would not be a genuine OTU
> (operational taxonomic unit),

OTU just means "line in a data matrix". Several specimen-level phylogenetic analyses (of other clades) have been performed.



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