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RE: [dinosaur] New Konzhukovia species (temnospondyl) from Permian of South America + Early Triassic polar coprolites + more papers
Tim Williams wrote-
>> Except that Phylocode doesn't
officially exist yet. There have been seven proposed phylogenetic
definitions for Tyrannosauridae, for instance.
> PhyloCode may not exist, but phylogenetic nomenclature does.
> Tyrannosauridae and Tyrannosauroidae are clades, and have been defined
> as such (more than once, as you note). Deinodontidae and
> Deinodontoidea have not been defined as clades - and nor is there any
> reason to.
if there's no official definition, why does it matter that they've been
defined? The phylogenetic definitions don't hold any weight. Take
Ornithomimidae, which was defined terribly by Sereno in 1998 and 1999 in
ways that didn't correspond to anyone elses' usage of the name. Was
the name then off limits to ICZN rules, even though it wasn't given a
definition most would agree with for almost a decade after that
(Kobayashi, 2008 in a paper most experts hadn't read until it was made
into a pdf last year)? That would be silly, but who's going to decide
when something has a decent enough definition that we can ignore the
ICZN from then on? I mean, Sereno thought the definitions were good and
he's one of the most prolific and famous paleontologists of the 90s.
If you say "well, once the community has gathered around a
definition..." that's the populist anarchy I noted.
None are official, but three define the same clade in Brusatte et al.'s
(2016) topologies. I'm sure some if not most break at least one
Phylocode rule as well. So you'd ignore the current rules for another
system which is supposed to work in conjunction with
>> them, and may not be enacted for years if ever.
> The fact remains that Tyrannosauridae has been defined
> phylogenetically as a clade. This should make it immune to being
> changed to something else (such as Deinodontidae), simply because of
> some arcane ICZN rule of priority regarding coordinated family-level
> taxa. _Deinodon_ is a nomen dubium, so it should be ruled out of
> consideration when naming clades.
happened before without incident- Sereno proposed and defined
Torvosauroidea and Oviraptoroidea, but later changed these to
Spinosauroidea and Caenagnathoidea respectively based on ICZN rules.
The former was then changed to Megalosauroidea. As for Deinodon being a
nomen dubium, that's just been an assumption for decades. Even if
further study convinced me it is undiagnostic, do you really want such a
subjective determination to be the basis for nomenclature? One
person's nomen dubium is another's diagnostic taxon, so which clade name
is valid would vary through history and between authors. Indeed, some
papers declare taxa to be nomina dubia in contradiction to their own
data, as in the temnospondyl paper that started this thread or Hocknull
et al. (2007) for Rapator.
>> Ah, but what if different
people pick different names? Are you actually arguing for a populist
anarchy in nomenclature?
> Firstly, these ICZN rules only apply to suprageneric groups that are
> coordinated family-level taxa. Diplodocidae and Diplodocoidea and
> Tyrannosauridae and Tyrannosauroidea are affected by ICZN rules;
> Diplodocimorpha and Tyrannoraptora are not. My argument is that
> clades ending in -idae, -oidea etc shouldn't be treated as special
> cases. For non-family-level-coordinated taxa, there is no "populist
> anarchy" when coming to naming clades - so why do you think this would
> happen with family-level-coordinated taxa?
actually is populist anarchy for clades not governed by the ICZN. Is
the ceratosaur+tetanurine clade Neotheropoda or Averostra? The
carnosaur+coelurosaur clade Avetheropoda or Neotetanurae? Is the clade
closer to modern birds than dromaeosaurids Avialae or Averaptora? Is
Aves crown birds or the clade of them plus Archaeopteryx? Is Ornithurae
taxa closer to living birds than Archaeopteryx, the
hesperornithine+crown group, or something involving pygostyle
development that is located around Ornithuromorpha? These are reasons
why we need the Phylocode to be enacted, so that it can have to power to
settle these disputes.
Mickey Mortimer<div id="DDB4FAA8-2DD7-40BB-A1B8-4E2AA1F9FDF2"><br />
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