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By that logic, I think you should be on my side. Diplodocus longus may be questionably diagnostic in its anatomy, but it is stratigraphically distinct, being the only tested Diplodocus from the lower Brushy Basin Member, while D. carnegii and D. hallorum are
from the upper Brushy Basin Member. This combined with the morphological differences appearing "to be more primitive" than D. carnegii (McIntosh and Carpenter, 1998) suggest D. longus may have been a distinct earlier species, even if there aren't any preserved
autapomorphies we can point to. That's the hypothesis I think is most likely anyway.
If you only care about naming real species, the actual "jiggery-pokery" is the current consensus that anatomical differentiation is necessary. You'd be advocating for a return to Huene's day, where if you find a type of organism in a new combination of place
and time, it's a good enough reason to name a new species. Which is actually probably correct in most cases, given our knowledge of how tightly constrained temporally established dinosaur species were. This ironically would support the recognition of far
more anatomically undiagnostic species, like the recently recognized Australian noasaurids, which while known from fragments near certainly don't represent named taxa based on geography alone.
But the current paradigm is to insist on anatomical differentiation, which is also what Tschopp does, as he'll have specimens which fall out away from named species in his tree (so they must have unique combinations of characters) but because of a lack of autapomorphies
he just calls them Diplodocidae indet. or whatever. So clearly his "insecurities and confusion" aren't the same consequences as your objection.
Mickey Mortimer
From: dinosaur-l-request@mymaillists.usc.edu <dinosaur-l-request@mymaillists.usc.edu> on behalf of Tim Williams <tijawi@gmail.com>
Sent: Friday, October 16, 2020 8:45 PM To: dinosaur-l@usc.edu <dinosaur-l@usc.edu> Subject: Re: [dinosaur] Diplodocus status Mickey Mortimer <mickey_mortimer111@msn.com> wrote:
> But that's just saying things should be how you feel they should be, without appealing to any specific consequence. You and Tschopp need to be able to say that "If we allow a type species to be > indeterminate within its genus, then if we have problem X it would be more difficult to solve." I've yet to hear a valid problem X for the ICZN, Phylocode or any other logical construct. Just vague > "insecurities and confusion" or in your case it being "bad." I don't see a species as simply a construct that is invented to satisfy ICZN rules. I see a species as a real biological entity. The ICZN may govern the rules of nomenclature, but it doesn't decide biology. Allowing a type species to be indeterminate within its genus is just jiggery-pokery to keep the genus going. The indeterminate species conforms to the ICZN Code, but it doesn't actually denote a real species in the biological sense. Taxonomically, retaining a nomen dubium as a type species gives the misleading impression that it's a separate species in its own right. In reality, it's just a bureaucratic placeholder. Scientific nomenclature should be about naming real species - not exploiting the arcane rules of the Code to prop up indeterminate species. |