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Re: [dinosaur] Canadian Society of Vertebrate Palaeontology abstract book + Truth About Tyrannosaurs + more
Mickey Mortimer <email@example.com> wrote:
> Note on page 56 that Mallon et al. seem to have found a more
> complete and diagnostic specimen of Ceratops, which is from the same
> formation and state. This would be a great time to declare it a neotype
> of Ceratops montanus, since they say the holotype's also
> indistinguishable from Albertaceratops and Kosmoceratops (from the
> Oldman and Dinosaur Park Formations, respectively). Then we'd have a
> well preserved and diagnostic type taxon / specifier. Alas, their
> wording seems to indicate they're going to name the specimen as a new
> species. :|
This would be the "bodacious" new ceratopsid. :-) However, your
statement that "Mallon et al. seem to have found a more complete and
diagnostic specimen of Ceratops" is your own interpretation, not
theirs. There is no compelling evidence that the new ceratopsid is
referable to _Ceratops_. Mallon &c only state that "the postorbital
horncores of the new species closely resemble those of the
contemporaneous ‘_Ceratops_’". They make no bones about the fact that
they regard _Ceratops_ as nomen dubium.
Yes, it is possible that this "bodacious" specimen represents the same
species as _Ceratops montanus_. (Another Judith River specimen [MOR
692, formerly referred to _Avaceratops_] could also be a potential
_Ceratops_ neotype]. But the only reason a neotype would be
contemplated at all for _Ceratops_ is because it's the name-bearing
genus for Ceratopsidae. In short: book-keeping. Otherwise, no one
would care. It's not as though _Ceratops_ itself has any enduring
popularity or standing in the literature - unlike _Diplodocus_, or
_Iguanodon_, or _Allosaurus_, or _Stegosaurus_ (genera for which
neotypes have been designated or proposed). When has _Ceratops_ ever
been included as an OTU in a phylogenetic analysis?
Personally, I'd like to see _Ceratops_ maintained as a valid genus
(such as by arbitrarily nominating a neotype, which is what you're
suggesting). But sadly, I suspect it's a lost cause.
> By the way, I noticed this week that Lihoreau et al.
> (2014) have done the right thing for ex-dinosaur Libycosaurus that I
> wish more dinosaur researchers would do. It turns out the holotype of
> the type species of Libycosaurus is lost and cannot be distinguished
> from the three valid species based on published information. So they
> just leave the type species as a nomen dubium (as it does belong to the
> clade formed by the other species), but also have three valid species in
> the genus too.
You may call this the "right thing" but I think this approach is bad
policy. If a genus has a nomen dubium as its type species, then the
genus should also be regarded as invalid. Or, nominate a new type
species in order to maintain the genus....
> That's what should be done with Diplodocus longus, but
> instead we have an ICZN petition to make D. carnegii the type species.
I'd say nominating _D. carnegii_ as the new type species of
_Diplodocus_ (along with a neotype) is a perfectly fine idea. I agree
entirely with the arguments of Tschopp & Mateus (Case 3700). The same
principal worked well for _Iguanodon_.