Re: [dinosaur] Do people still use Troodon?

[Tim Williams <tijawi@gmail.com>]

Fair enough.  We don't need to split the Ceratopsidae into two
families.  Just rename it Centrosauridae (I believe Centrosauridae
would have priority over Chasmosauridae, by virtue of Centrosaurinae
appearing before Chasmosaurinae (by one line) in Lambe, 1915).

I also take your point that we should keep things the way people are
used to.  The name Ceratopsidae is certainly time-honored.  The
problem is that any phylogenetic definition of Ceratopsidae must
include _Ceratops_, as the nominative (name-giving) taxon.  But
_Ceratops_ is not a taxon (or OTU); it's a nomen dubium.  So something
has to give.




On Sun, Nov 22, 2020 at 8:08 PM Yazbeck, Thomas <yazbeckt@msu.edu> wrote:
>
> Centrosaurs+chasmosaurs (ommitting suffixes for neutrality) are quite 
> obviously a monophyletic clade though. What do you call the clade they 
> comprise? And is Ceratops diagnostic enough to be placed in one of the two 
> subfamilies? It's obviously a member of the centrosaur+chasmosaur clade, as 
> we have no reason to suspect more basal ceratopsians with horns existed in 
> the locality Ceratops was found in. I think it's pointless to bump up the 
> ranks and buck a century long tradition of using Ceratopsidae consistently in 
> circumscription.
>
> I feel as if splitting Ceratopsidae into two families wouldn't catch on 
> anyways, because in phylogenetics the names of clades technically don't 
> really matter so much as the composition of the clade itself. The family 
> could be called "78041", and still be perfectly fine, and it's convenient 
> because Ceratops itself almost certainly belongs in it somewhere (probably in 
> Centrosaurinae, I would argue). Ceratops is complete junk for a phylogenetic 
> analysis but it's clearly Ceratopsidae incertae sedis. I guess I just believe 
> in keeping things the way people are used to, although I must admit there's a 
> sense of tidiness gleaned from casting nomina dubia into the abyss.
>
>
> Thomas Yazbeck
>
> ________________________________
> From: dinosaur-l-request@mymaillists.usc.edu 
> <dinosaur-l-request@mymaillists.usc.edu> on behalf of Tim Williams 
> <tijawi@gmail.com>
> Sent: Sunday, November 22, 2020 12:52 AM
> To: dinosaur-l@usc.edu <dinosaur-l@usc.edu>
> Subject: Re: [dinosaur] Do people still use Troodon?
>
> I don't think it's sensible to have families named after nomina dubia.
> So from that perspective, Troodontidae should be called
> Saurornithoididae.  I also think it would be practical to discard
> Ceratopsidae and split it up into two families, Centrosauridae and
> Chasmosauridae.
>
> The reason why families should NOT be named after indeterminate genera
> is because a family must include the name-giving genus (which makes
> sense).  So Ceratopsidae must include _Ceratops_.  But if _Ceratops_
> is a nomen dubium, it should not be treated as a taxon, and it should
> not be used as an OTU in a phylogenetic analysis.  There is/was no
> creature called _Ceratops_; it's just a name.   Genus _Ceratops_ is a
> zombie: it's a dead name that's kept alive purely for bookkeeping
> reasons, simply because it gives its name to Ceratopsidae.   I know
> the ICZN allows this sort of thing, but from a biological standpoint
> it's antiquated and bizarre.
>
>
> On Sat, Nov 21, 2020 at 4:48 PM Ethan Schoales <ethan.schoales@gmail.com> 
> wrote:
> >
> >
> > Isn't Ceratops already obsolete? It's technically the type genus of 
> > Ceratopsidae, but it might as well not be.
> >
> > On Sat, Nov 21, 2020 at 12:46 AM Tim Williams <tijawi@gmail.com> wrote:
> >>
> >> Ethan Schoales <ethan.schoales@gmail.com> wrote:
> >>
> >> > I've seen some recent papers on the DML that use it as valid, but Zanno 
> >> > et al. 2017 declared it dubious due to its non-diagnostic holotype. 
> >> > Basically, what people worried would happen to Diplodocus, hence the 
> >> > petition.
> >>
> >> Yes.  Hence the petition,   :-Z
> >>
> >> > I wonder if, in a few decades, if not sooner, Troodon will be where 
> >> > Trachodon is now - a name you only see in old books
> >> >
> >> > But I think that declaring that we can no longer use a name that's been 
> >> > widely used for over 150 years is a bad idea.
> >>
> >> While it's true that the name _Troodon_ has been around since 1856,
> >> it's had a very tortuous taxonomic history.  For a while (~1924-1945)
> >> _Troodon_ was considered a pachycephalosaur., before being recognized
> >> (again) as some kind of theropod.  It was only in 1987 that _Troodon_
> >> was recognized as belonging to the same family as the better known
> >> _Stenonychosaurus_ and _Saurornithoides_, and the family was therefore
> >> given the name Troodontidae.  (I prefer Saurornithoididae, but I'm
> >> fighting a losing battle on that front.)  So although the name
> >> _Troodon_ has been used for over 150 years, it hasn't been
> >> consistently used.
> >>
> >> Personally, I'd like to see _Troodon_ retained as a valid genus via
> >> nomination of a neotype (subject to ICZN approval).  But unless that
> >> happens (which seems unlikely), the name _Troodon_ will indeed go the
> >> way of _Trachodon_.  Sadly, _Ceratops_ and _Titanosaurus_ will
> >> inevitably suffer the same fate.