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Re: Oviraptor



<Jaime keeps mentioning the Cenomanian-Campanian boundary...apparently
forgetting all about the intervening Turonian, Coniacian, and Santonian Stages.>

My mistake using Cenomanian in lieu of the Santonian. One did not need to get
nasty about it.

<Biostratigraphic correlations are utterly meaningless when based upon taxa that
are not CONSPECIFIC.  Genera cannot be correlated, families cannot be
correlated, ONLY species can be correlated.  Thus, correlating Asian and North
American faunas is absolutely borad-brush unless the same species are being
used.  Geochronology is your friend...do not be afraid of it.>

  Ah, yes, the magic of the "genus." I have noticed before the use of a presence
of inferrence of identity of a specimen as a particular genus to prove a
particular formation is not in the Carnian or other stage, especially in
consideration of Lucas and Hunt's work on biostrat in dating portions of the
Dockum Group using aetosaurs and phytosaurs, and determining a taxon's age
because a magical phytosaur genus occured in the same level. Similar genera are
other workers' similar congeneric species are other workers' similar conspecific
specimens/subspecies. This works with some very well-sampled ammonite faunas and
foraminifera, of which thousands of the same species or subspecies have been
recognized from specimens. Of course, if your fave p;rof says that a species
indicates an age, it MUST be true, because that species cannot cross this
magical boundary between, say, the Rhaetic and the Vallanginian. Though biostrat
is very useful, it has its limits when the identification of genera is
subjective. Just look at the arguments for and against dinosaurian genera and
species references: how close does a species have to be to be considered
congeneric? The same level can be drawn to the species level, just as subjective
an identification if one separates two species based on anatomy that another
would call subspecific variation on their own recognition of these two forms as
a single species.

  Biostrat has one major flaw, and that's that it falls apart if people
reidentify species and genera based on non-geologic data, and their referral
based on it ignores that speciation does not care what strata a species is
recovered in millions of years later. There are uses, then there are not uses,
and its all relative.

  Using some specific examples for this thread, I can draw the following
anecdote:

  The Heyuan Basin of China and the Barun Goyot of Mongolia both produce
"genera" of oviraptorids, *Heyuannia* and *Ingenia,* respectively, that may be
considered synonyms under the presence of identification of the manus structure
as autapomorphic of a genus, *Ingenia* by priority (other manus features that
are different would be expected between species, even, as partial fusion of the
distal carpal to the second metatarsal in *Heyuannia* only exists palmarly,
suggestive of a abnormality or possible ontogenetic feature) -- therefore, the
Heyuan and Barun Goyot bear consistent age because the same genus is found in
the two. Ignore other data.

  Cheers,

  Jaime A. Headden

  Little steps are often the hardest to take. We are too used to making leaps in
the face of adversity, that a simple skip is so hard to do.  We should all learn
to walk soft, walk small, see the world around us rather than zoom by it.

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