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RE: Sauropodz r kewl WAS silly ramble



David Marjanovic wrote:

<He's using a genus _name_ as a _clade name_. I really can't see why he 
shouldn't.>

  He's using the concept of the rank, as is present in his paper and in his 
SV-POW! posts on the paper. Just for example, there's this from pg. 798 in 
Taylor, 2009:

  "Although McIntosh (1990b:65) felt that “the coracoid, femur, and sacrum of 
the two species are in complete accord,” differences exist in both coracoid and 
femur, as well as the humerus, ilium, caudals, and most significantly the 
dorsal vertebrae. Since poor preservation prevents detailed comparison of the 
sacra, and lack of information about ribs makes it impossible to evaluate the 
significance of observed differences, these elements are therefore 
uninformative for comparative purposes. All elements sufficiently well 
preserved in both species, then, exhibit distinct differences, and generic 
separation is warranted since the two species are more different from each 
other than, for example, Diplodocus and Barosaurus Marsh, 1890. Accordingly, 
the name Giraffatitan will be used in the remainder of this paper."

  Aside from extensive use of the term "genus" in the paper, derivatives of 
that noun, and its use on the website, Taylor has come down on the side of 
preferring uninomials, and I appreciate his condor on this. However, this 
doesn't condone the extensive use of the term regardless of its loaded lack of 
value. Moreover, regardless of preferring uninomials, Mike consistently uses 
the "praenomens" over any combination of it and the species epithet in the 
paper (which rather enforces the subjective value the "genus" places in our 
language and nomenclature).

  I agree with Mike that the specific case of *Giraffatitan brancai* makes 
sense -- if it weren't predicated on the unquantified issue of how much 
variation equals generic separation (the secondary premise of the paper). 
Attempting to qualify "genera" on the basis of an unquantified variable, even 
more interesting given the current trend of SV-POW! posts referring to Woodruff 
and Fowler's 2012 paper on subjective ontogeny in diplodocoid sauropods.

<Please explain what you mean by "concordant value" and "intrinsic value".>

  I may need to use "relative value" instead, but...
  Specimen MPC-D 100/978 is _intrinsic_ to the "nature" of *Citipati 
osmolskae*, as it represents the type specimen. Specimen MPC-D 100/979 is 
_concordant_ with the nature of *Citipati osmolskae*, as it represents a 
specimen that is morphologically similar or nearly identical with the 
postcrania of MPC-D 100/978. In this way, concordant means "aligns with," 
"agrees with," but is far more specific than a generalization.

  In use: Ranks are concordant to taxa in particular positions on a phylogram, 
but they are not intrinsic to the position of said taxa on the cladogram. 
(Despite this, position of taxa move and may or may not take their "ranks" with 
them.)

<Given the high probability that *Brachiosaurus* and *Giraffatitan* are not 
sister-groups, it was a good move to separate them nomenclaturally.>

  What probability? One analysis, so far, was inconclusive on this regard 
(Taylor's). It made the presumption that morphologic variability = generic 
separation, but did not prove this case. It can't be proven on such a ground, 
simply because the existence of the "genus" is both subjective and 
non-intrinsic to biology. But notice that the sentence YOU WROTE alludes to the 
idea that what you are referring to is either
  1) a uninomial (which might exclude use of the "species," as if it didn't 
matter or exist) or
  2) the very convention my post referred to, where "genus" is given primacy as 
the currency of taxonomy, ignoring that it does not actually represent anything 
to do with "species" in the system of note.
  If anything, the system is actually a mishmash of Phylogenetic Nomenclature, 
the ICZN, and some unholy offspring bred back to the original (ignoring the 
existence of "species").

  You see, the names are already separated nomenclaturally: *brancai* and 
*altithorax* are substantially different from one another. Separating them 
further requires you to continue to presume that *Giraffatitan* and 
*Brachiosaurus* are different from their contained names, and that is what I've 
been getting at.

  Once again, this is not meant to hash on Mike. He and I have had our back and 
forth, and I'd like to work on rebuilding some sort of positive relationship 
without giving up the integrity of my premise, that the use of ranks is 
unscientific, and hypocritical of authors to claim otherwise when validating 
their nomenclatural changes.

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, 17 Apr 2012 14:48:18 +0200
> From: david.marjanovic@gmx.at
> To: dinosaur@usc.edu
> Subject: Re: Sauropodz r kewl WAS silly ramble
>
> Am 17.04.2012 14:09, schrieb Jaime Headden:
>
> > It was not my intention to be hostile, so the tone of the response I
> > received from Mike seems particularly odd.
>
> But apparently it wasn't sent to the list (I haven't received it), so
> there's probably no point in discussing it here...
>
> > Consider that the commentary of this entire thread has been on the
> > efficacy of certain names, especially referring to *Brachiosaurus* as
> > an equivalence to *Brachiosaurus altithorax*, which in zoological
> > terms would be just *B. altithorax* for the most part.
>
> (Point taken, but even neontologists don't abbreviate genus names before
> they've spelled them out once.)
>
> > [...] *Brachiosaurus*, being capitalized, it the primary element of
> > the name, a fault I'd rather lay at the feet of Linnaeus than anyone
> > else, but a typical effect in the classical language he was using.
>
> It's not simply a side effect of the default word order of Latin;
> Linnaeus deliberately employed it because of his philosophy. To him, the
> genus really was the basic _general_ unit, and the species was
> _specific_. It was an additional subdivision diagnosed by "less
> important", less "general", more "specific" characters. The modern
> emphasis on species as units of biodiversity and genera as a
> biologically meaningless rank is much younger; Linnaeus thought that
> genera were real.
>
> > and even the ICZN doesn't tolerate or regard anything higher than
> > "family-level" ranks.
>
> Not true. Most rules (such as priority) don't extend above the family
> group of ranks, but the use of higher ranks is not at all discouraged.
>
> > Growing is the movement to abandon ranks, and their concordant
> > problems. I've written on this on my blog ad nauseam, and of course
> > many of the offenders have defended their choices, but all of them
> > have and will continue to use "genus" without any care for its lack
> > of scientific value. When Mike argues about what I'm talking about,
> > his very message is ripe with the problem I speak of, his continuing
> > demonstration that despite knowing a genus means nothing, _he's still
> > using it_.
>
> He's using a genus _name_ as a _clade name_. I really can't see why he
> shouldn't.
>
> > When Mike says "[t]hey're just names on characteristic specimens",
> > then he really doesn't understand the problem to its extreme:
> > scientific nomenclature names the specimens as proxies for a set of
> > organisms, but the "genus" and the "species" are completely different
> > from the _specimens_,
>
> The names are attached to the type specimens; the set of organisms
> consists of the type specimen and, in practice (at least in
> paleontology), all others that are similar enough to it.
>
> > and intend to describe instead a set without any concordant value.
> > _They have no intrinsic value_.
>
> Please explain what you mean by "concordant value" and "intrinsic value".
>
> > I similarly have no problem with a taxon named *Giraffatitan* or
> > another named *Brachiosaurus*. What I have a problem with is people
> > determining that a taxon named *brancai* MUST or SHOULD be divided
> > from *altithorax* in a fixed fashion that can be comapred to other
> > issues, like how to divide *Psittacosaurus* into neat, clean "genera"
> > or whatever.
>
> These two cases are the same as far as the ICZN is concerned, but not as
> far as the practice of the last few decades is concerned.
> *Psittacosaurus* as currently understood is, apparently, monophyletic.
> *Brachiosaurus* as it used to be understood is probably not
> monophyletic; in addition to Mike's own phylogenetic analysis which
> showed a lack of evidence for monophyly, there's one that finds it to be
> para- or polyphyletic (I don't remember) and was presented at last
> year's SVP meeting. The ICZN is fine with para- and even polyphyletic
> genera; but few biologists these days are. Given the high probability
> that *Brachiosaurus* and *Giraffatitan* are not sister-groups, it was a
> good move to separate them nomenclaturally.
>
> > [...] paleontologists and zoologists may have directly contradicting
> > views on species identification, despite using the same nomenclatural
> > system.
>
> Different neontologists have very different views on species
> identification, too. There is much controversy over many individual
> cases and over general questions like whether subspecies should be
> recognized at all (as opposed to promoting them to species rank).