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RE: Australodocus a titanosauriform and other new papers



Tim Williams wrote:

<Witlock's argument that tradition should carry the day is spurious, and goes 
against the grain of phylogenetic taxonomy.>

  I would actually disagree with Whitlock on this issue, if true, simply 
because tradition should be subjected to greater scrutiny than the unfamiliar, 
because it biases our perceptions of virtually everything.

In response to Mickey Mortimer (post below):

  ANY named clade containing a species "implies monophyly" when it is expressly 
used to do so. If this is true, then *Brachiosaurus* could have been used to 
contain (monophyletically) *brancai*. Taylor argued on other grounds that it 
_shouldn't_, not that it couldn't. I am arguing that if you can keep it in, and 
there is no phylogenetic reason to remove it, don't. This is the point of the 
"originalism" position. "Genera" have baggage, and I argue this as well. They 
do not mean "clade," they refer to a special category that contains also but is 
not contained, by species, and that cannot itself be contained by genera. In 
this sense, it's just a positional label. The utility of the "genus" as 
Linnaeus used it and has been used in the last two centuries (more or less) 
does not refer to a clade: it refers to a ranked position for which a name is 
_required_ when containing also a species. It is a category that is literally 
no different from "family" or "order," "class" or "kingdom" or even "domain." 
In this sense, we hit a problem: what do we do with nomenclature that lies 
between "genus" and species? 

  Taylor argued that, arbitrarily but based on Linnaean precedent, elevating a 
"subgenus" to "genus" was the useful thing at this point, but as I argued, this 
is not useful at all. Taylor did not argue communication was his criterion: he 
was applying the Linnaean system to the nomenclature, and trying to split 
overemphasize by traditional splitting. One may be offended by this practice if 
he were to create a "Giraffatitanidae" to also emphasize this distinction, or 
further, as was done with various mammalian and avian "orders" (often monotypic 
to the _"genus"_), but it is "enough" and "useful" to only go to the "genus." 

  Because there is no _science_ inherent in the Linnaean System -- that is to 
say, in the Popperian sense, it makes no disprovable argument -- its value is 
reduced. I argue that it becomes art. *Giraffatitan* is art, and so is the 
"genus." We can also argue about _species_ being art, but that's slightly 
different (and again because it's laden with baggage).

  I want to make it clear that on a communicative level, the formation of 
taxonomic nomenclature is useful in the sense of naming things familiar to use 
("bird," "Jaime Headden," "that freakish weird dude over there"), and that in 
this sense, *Giraffatitan* has value. It is useful if we want to create 
bionomial nomenclature without the use of "genera" as much as with it, and it 
allows us to convey the sense of importance or quality. But these are reasons 
based on our expectations, drawn from our familiarity with the Linnaean System. 
And if that is flawed, shifting our reasons to support its precedent must also 
be flawed. I argued that the PhyloCode handles this subject just as well and 
with fewer complications on the nomenclatural expectations (allowing even 
lowercase-only species nomenclature), and as such there are other systems to 
use. But *Giraffatitan* is not useful if we presume a phylogenetic reasoning is 
true, and cannot recover it to the exclusion of better data (i.e., more of it). 
I do not think that *Giraffatitan* cannot be used, but that without substantive 
support for the placement of the "brachiosaurids" being argued about, the use 
of it -- and any other "genus" in question, including *Sonorasaurus* and 
*Cedarosaurus* -- is a taste issue that detracts from the science involved. It 
tells us that even had we supported sister relationships down the road, we'd 
still prefer then to use *Giraffatitan* alongside *Brachiosaurus* because of 
the level of publicity involved. There should be no better example of this than 
the continued use and popularity of *Brontosaurus,* and I think you are all 
aware of it, but either dismissing its effect or want to use this because of 
the "cool" factor (as in Taylor et al. naming *Brontomerus*, or Yates et al. 
*Antetonitrus* (although less popularized)).

Cheers,

  Jaime A. Headden
  The Bite Stuff (site v2)
  http://qilong.wordpress.com/

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


"Ever since man first left his cave and met a stranger with a
different language and a new way of looking at things, the human race
has had a dream: to kill him, so we don't have to learn his language or
his new way of looking at things." --- Zapp Brannigan (Beast With a Billion 
Backs)


----------------------------------------
> Date: Tue, 12 Jul 2011 00:16:48 -0700
> From: mickey_mortimer111@msn.com
> To: dinosaur@usc.edu
> Subject: RE: Australodocus a titanosauriform and other new papers
>
>
> When we discussed this on your blog, we narrowed our disagreement down to the 
> fact that you don't see genera as clades.  But I can assure you that Taylor, 
> Williams, myself and most others on here DO think of genera as being clades.  
> Thus retaining brancai in Brachiosaurus implies it is in a clade with 
> altithorax to the exclusion of Sonorasaurus, Cedarosaurus and every other 
> named genus.  And THAT's the reason we all have a problem with it.  You may 
> view genera as just Linnaean labels, but most of us see them as implying 
> monophyly.
>
> Mickey Mortimer
>
> ----------------------------------------
> > Date: Tue, 12 Jul 2011 00:05:04 -0600
> > From: qi_leong@hotmail.com
> > To: tijawi@gmail.com; dinosaur@usc.edu
> > Subject: RE: Australodocus a titanosauriform and other new papers
> >
> >
> >
> > Whitlock's issue is the same one I had (here: 
> > http://qilong.wordpress.com/2011/03/11/systematic-originalism/) when 
> > dealing with Taylor resurrecting Paul's otherwise unused *Giraffatitan*: 
> > The use of *Giraffatitan* superimposes the idea or concept of "genus" on 
> > the discussion of diversity; that "brachiosaurids" are _more diverse_ than 
> > previously argued; that *altithorax* and *brancai* have a lot of 
> > differences, but that *altithorax* vs. *brancai* is "insufficient" to 
> > recognize this; and that no analysis published supports placing *brancai* 
> > anywhere else than next to *altithorax* -- and when highlighting this 
> > latter argument, Taylor failed to support it when splitting them and then 
> > testing them cladistically.
> >
> > The argument that we are better at facilitating communication by using a 
> > binomen, in this case a genus-species couplet (as used by Taylor when 
> > resurrecting the taxon name), fails because the objective value of the 
> > genus is inherently tied to a failed systematic system, the Linnaean 
> > System. Taylor's reply on my argument against this pattern was "What other 
> > system have we got?" What other, indeed. This is ridiculously silly because 
> > at the time Taylor supported this argument, he was also supportive of 
> > PhyloCode, which does not treat genera as valid objects. You either have a 
> > species, or a clade. And a clade containing only a species collapses to 
> > that species, meaning this object is redundant. And this is where we are 
> > going, right now: creating redundant clades containing only a single 
> > species for fossil taxa, as if it means we are recognizing new, special 
> > taxa. Many of the systematists who do this even recognize the idiocy of the 
> > genus-species couplet.
> >
> > There is only one validation I can see for this nomenclature, and that's if 
> > and when *brancai* arises apart from any monophyletic clade containing 
> > *altithorax* _consistently_, or if we just abandon the idea of nesting 
> > _species_ and just create binomina for all species taxa. This means we get 
> > *Brontosaurus* back, incidentally. But I doubt that the latter will happen 
> > any time time, and I doubt anyone will abandon the sexiness that is naming 
> > "genera" for all the notoriety and attention these "special names" bring to 
> > the field. And seriously, I suspect this is why a lot of otherwise 
> > "lumpable" taxa get named in the first place, despite the lack of a 
> > "difference" metric that seems presumed by a host of authors.
> >
> > Cheers,
> >
> > Jaime A. Headden
> > The Bite Stuff (site v2)
> > http://qilong.wordpress.com/
> >
> > "Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)
> >
> >
> > "Ever since man first left his cave and met a stranger with a
> > different language and a new way of looking at things, the human race
> > has had a dream: to kill him, so we don't have to learn his language or
> > his new way of looking at things." --- Zapp Brannigan (Beast With a Billion 
> > Backs)
> >
> >
> > ----------------------------------------
> > > Date: Tue, 12 Jul 2011 14:34:37 +1000
> > > From: tijawi@gmail.com
> > > To: dinosaur@usc.edu
> > > Subject: Re: Australodocus a titanosauriform and other new papers
> > >
> > > bh480@scn.org wrote:
> > >
> > > > John A. Whitlock (2011)
> > > > Re-evaluation of Australodocus bohetii, a putative diplodocoid sauropod
> > > > from the Tendaguru Formation of Tanzania, with comment on Late Jurassic
> > > > sauropod faunal diversity and palaeoecology.
> > > > Palaeogeography, Palaeoclimatology, Palaeoecology (advance online
> > > > publication)
> > > > doi:10.1016/j.palaeo.2011.07.001
> > > > http://www.sciencedirect.com/science/article/pii/S0031018211003579
> > >
> > >
> > > I'm not qualified to comment on the merits of the assignment of the
> > > cervicals named _Australodocus_ to basal Titanosauriformes... but two
> > > things come to mind:
> > >
> > >
> > > Firstly, if _Australodocus_ is *not* a diplodocoid, does that mean
> > > that all the diplodocid material from Tendaguru can be returned back
> > > to _Tornieria_?
> > >
> > >
> > > Secondly, I'm bewildered by Whitlock's reasoning for sinking
> > > _Giraffatitan_ into _Brachiosaurus_:
> > >
> > > Although numerous morphological differences exist between B.
> > > altithorax and B. brancai, the genus Brachiosaurus has never been
> > > demonstrated
> > > to be polyphyletic. Failing that, without a recognized criterion
> > > for determining
> > > whether two taxa are either distinct palaeospecies or palaeogenera based 
> > > on
> > > morphology alone, the decision to replace an existing name (in this case,
> > > Brachiosaurus) with a different one (Giraffatitan) must be seen as 
> > > somewhat
> > > arbitrary. Because low-level palaeotaxa are perhaps best seen as 
> > > convenient
> > > shorthand for facilitating discussion and not as equivalents of
> > > neontological
> > > species or genera, it may be preferable to retain existing names whenever
> > > possible and thus maintain consistency with what is often decades
> > > of previous
> > > scholarship.
> > >
> > >
> > > Jee, I don't know about that. I'm not sure that fossil genera and
> > > species should be seen as "convenient shorthand for facilitating
> > > discussion". That seems excessively cynical to me - and lazy. But
> > > even if we follow Whitlock's advice (and I'm by no means suggesting
> > > that we should), keeping _Giraffaititan brancai_ in _Brachiosaurus_ is
> > > still a bad idea because it facilitates the *wrong* sort of discussion
> > > - such as overstating the commonalities in the dinofauna between the
> > > Morrison and Tendaguru. (Ironically, Whitlock's study actually
> > > emphasizes how different the Tendaguru environment was from the
> > > Morrison, and highlights the impact this had on relative sauropod
> > > diversity and browse regimes.)
> > >
> > >
> > > Further, to "maintain consistency with what is often decades of
> > > previous scholarship" raises alarm bells, because a large portion of
> > > this previous scholarship sometimes involved low standards for
> > > taxonomy. And by 'low', read 'crap'. Nearly a century ago, Tendaguru
> > > taxa were lumped into established Morrison genera unless there were
> > > compelling reasons not to (like _Kentrosaurus_). It was Janensch's
> > > default setting. Janensch's reasons for assigning the Tendaguru
> > > species _brancai_ to _Brachiosaurus_ were highly suspect, especially
> > > considering that he had never seen the North American _B. altithorax_
> > > material. As further noted by Taylor (2009), "Because this assessment
> > > did not describe specific derived characters shared between the
> > > Tendaguru forms and _Brachiosaurus altithorax_, it would not be
> > > considered a valid justification for the referral if published today."
> > > I aver we should be using current standards for dinosaur taxonomy,
> > > not those exercised at the beginning of the last century.
> > >
> > >
> > > To make the taxonomic issue more confusing, Whitlock's comparison of
> > > _Australodocus_ to _Brachiosaurus_ concludes:
> > >
> > > Whether these differences are sufficient to differentiate them at
> > > the generic level
> > > is uncertain. In a purely utilitarian sense, the argument is
> > > unnecessary - the names
> > > as known serve to distinguish between the taxa, regardless of the
> > > signifier used -
> > > and so _Australodocus_ is retained here.
> > >
> > > So for the sake of tradition and convenience, African _Giraffatitan_
> > > gets put back into North American _Brachiosaurus_ - but a second
> > > presumptive brachiosaur from Tendaguru (_Australodocus_) remains as a
> > > standalone genus...despite the stated opinion that it is "uncertain"
> > > whether the two Tendaguru titanosauriforms can be differentiated at
> > > the genus level?! I'm not warming to this purely utilitarian approach
> > > one bit.
> > >
> > >
> > >
> > >
> > >
> > > Cheers
> > >
> > > Tim
> >
>