Re: Titanoceratops, giant ceratopsian from New Mexico

["Andrew A. Farke" <afarke@gmail.com>]

I figured I should jump into the fray too. . .

On 12/30/2010 04:19 AM, Denver Fowler wrote:
> It's astonishing how many of "Titanoceratops"'s characters are known to vary
> (strongly) ontogenetically; I see no reason to split off the OMNH Pentaceratops
> into a new genus and species: it is entirely consistent with being a mature
> Pentaceratops.

Agreed.

> Should we be splitting up all the ceratopsid growth series into
> different taxa? They certainly have different morphologies, but then that's
> because animals change as they grow.

No - but it also depends on agreement that we're looking at growth 
series. There's no question with taxa like Centrosaurus, Styracosaurus, 
Pachyrhinosaurus, etc., where you have bonebeds. The great majority of 
ceratopsid workers accept that various skulls called Monoclonius are 
juveniles of this or that centrosaurine. I think the only major sticking 
point right now is in Torosaurus/Triceratops. I would agree that this is 
a testable hypothesis, simply due to the large sample size (especially 
for the Triceratops morph).

> I am coming ever closer to the view that we're going to see a schism in dinosaur
> science; at least in ceratopsid workers, with one side splitting all ontogenetic
> and stratigraphic morphs into different taxa, and the other studying ontogenetic
> shifts through time. Taxa are testable hypotheses using ontogenetic and
> stratigraphic data. if you are just using morphology, then it's a judgement
> call, and not much different from the way taxonomy was conducted 100 years ago.

If it's truly going to be such a schism, then I suspect neither "side" 
is doing science! The greatest danger is the practice that "When the 
only tool you have is a hammer, every problem is a nail." This plays 
both in the direction of assuming all morphological differences are 
taxonomically significant, as well as assuming all morphological 
differences are ontogenetic in nature (to oversimplify grossly). I'm not 
saying that the happy middle is correct (a fallacy in its own right), 
but I would urge caution in veering too far in either direction for 
every taxonomic problem. That said, the recent work on Triceratops has 
been providing some fantastic data to address these questions.

> I can't see it is possible to continue with one side trying to convince the
> other: look at Longrich's discussion of Triceratops-Torosaurus. I hesitate to
> call Triceratops-Torosaurus a complex problem (I think it actually simplifies
> things), but Longrich goes into such little detail it feels very dismissive.

I agree that too little detail is provided; however, I'm sure the editor 
wouldn't have wanted a huge digression on the topic in the middle of the 
manuscript!

> Saying that there are no intermediates is absurd: we see nothing but
> intermediates with the squamosals and other parts of the skull. Why don't we
> find some parietals with tiny fenestrae (ie. intermediates)? because that's not
> how the fenestrae form, and if you read the papers and look at specimens, you'll
> see it.

Diceratops/Diceratus/Nedoceratops does have tiny fenestrae.

> New specimens are revealing more data on this; but be patient, we
> collected so many new Triceratops (with the essential strat data) it takes time
> to prep them all.

Like. :-)

I would also note that I strongly disapprove of the introduction of 
"Triceratopsini". We have enough clade names cluttering up the 
literature already.

Look for much more on this part of the tree in the next few weeks.

Andy