[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: New papers in Geobios (and nomenclatoral gripe)

Michael Mortimer (mickey_mortimer111@msn.com) wrote:

<But a genus is just another clade, like a family. And a species can be
indeterminate within various levels of taxonomy, including genus.  Here's my

<Hadrosaurus may be indeterminate within 'family-level' (Prieto-Marquez et al.,
2006).  The oldest name for a family containing Hadrosaurus is Hadrosauridae. 
Because it's still definitely a hadrosaurid (in the sense it belongs to this
certain 'family-level' clade; not because in ICZN/Phylocode it would have to be
a member of its eponymous family), it can remain the type genus for that
family.  Hadrosaurus is merely an indeterminate genus, alongside diagnosable
genera like Edmontosaurus and Parasaurolophus.  Of course, foulki is a nomen
dubium too, because it is within Hadrosaurus (by definition) and can thus only
be placed as accurately as its genus.>

  Mickey, your analogy may be bad wording, or an attempt to use rank-based
terminology, but the reason *Hadrosaurus*, while indeterminate for the most
part, is still a hadrosaurid, is that it remains grouped phylogenetically
within a group of dinosaurs for which the name Hadrosauridae has been applied,
either classically or phylogenetically. In so far as *Hadrosaurus* remains
bound in that group, that group will be Hadrosauridae. It may later appear
impossible to group it there, or it will group outside (highly unlikely as the
material DOES possess distinct apomorphies, but the possibility exists), but
only then can we -- phylogenetically at least -- disband use of Hadrosauridae
for the group because *Hadrosaurus* is no longer a part of it. That, or
*Hadrosaurus* takes it's container with it.

  Similarly, unless *foulkii* itself is regarded as a nomen dubium,
*Hadrosaurus* will be valid and NOT a nomen dubium; it works from the base up,
not the pinnacle down. Since *foulkii* is based on the type specimen, and may
be bolstered by explicitly -- in my dreams, anyway -- referred material (that
is, the material overlaps the type material and is, for all intents and
purposes, identical), the specimen itself would need to be "generically"
indeterminate (whatever _that_ really means) to render *Hadrosaurus* a nomen
dubium. Now, I personally think, as I am sure Mickey does as well, that if you
can distinguish a specimen from other type specimens or their hypodigms, your
specimen is diagnostic and is valid. This appears to be the case for *foulkii*
even though it appears to lack apomorphies; thus I would never claim it would
be a nomen dubium unless so compelled by further evidence that it could
possibly pertain to other taxa or that biogeography suddenly _means_ something
serious, systematically.
<suessi may be interminate within 'genus-level' (Sachs and Hornung, 2006). The
oldest name for a genus containing suessi is Mochlodon.  Because it's still
definitely Mochlodon (in the sense it belongs to this certain 'genus-level'
clade; not because suessi is the type species of Mochlodon), it can remain the
type species for that genus.  suessi is merely an indeterminate species,
alongside diagnosable species like robustus and shqiperorum.  Mochlodon isn't
necessarily a nomen dubium though (unlike the previous example), because it
isn't within suessi, it's more inclusive than suessi.  Just like how
Hadrosauridae can be diagnosed even if Hadrosaurus can't.>

  Hadrosauridae follows different conventions and rules than does *Mochlodon*,
at least in the here and now. However, Mickey, you are applying some
problematic thinking on the part of assuming that *suessi* belongs to any
"genus"-level group named *Mochlodon* without excepting that it's the type
species, since it is the latter that has framed the argument in which the ICZN
has been dragged onto THIS list. If *Mochlodon* itself has no valid anchor to
place it (the type species), then the name *Mochlodon* is not diagnosable (or
at least definable). Gone are the days of genera being diagnosed differentially
than their species, or so I'd like to hope, and the practice is (slowly) going
out of practice from current dinosaur and herpetological and ornithological
papers I've been reading, though sadly not TOO fast.

  *Mochlodon* does NOT exist as a valid marker if *suessi* itself does not
exist as a valid marker. Yes, the names are still available, but unusable as
long as the type specimen of the type species of the genus is not determinate.
In this case, it "seems" to have a dentary a lot like *Zalmoxes*' species, at
which point it "might" be *Zalmoxes*-ish, so is placed there, and *Mochlodon*
is rendered to the dust bin until at some point someone can show how *suessi*
IS a valid nomen (and this via a juvenile mandible!).

  Now, perhaps somewhere, there will come a time that *Mochlodon* has a
differential form of existence that does not depend on *suessi*'s validity, but
that should one arise from the dust bin, then together they shall be wed
forever, but this time is not now. No one (I think) wants to start making every
single name available in taxonomy completely independant of one another, so
that *Mochlodon* can somehow be valid despite *suessi* being a nomen dubium and
unavailable for the purposes of synonymy -- as we seem to be agreeing on at
this point. (Otherwise the practice of designating new type species to rescue
classic names would fall to the wayside, as Tim's example of *Iguanodon*


Jaime A. Headden

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

Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around