Re: Caenagnathiformes named 31 years ago!!

["Jaime A. Headden" <qilongia@yahoo.com>]

Ken Kinman (kinman@hotmail.com) wrote:

<Of course, it now contains a whole lot more forms, but their avian nature
was recognized by Cracraft over 30 years ago.  So it seems my expansion of
Aves isn't all that radical a change after all.  This has really made my
day!!!!>

  I've thought about this for a while, and decided something should be
said before anybody gets the wrong idea.

  Cracraft, like Sternberg before him, thought that the jaws of
*Caenagnathus collinsi* and Cracrafts taxon *C. sternbergi* (to honor the
genus' describer) were those of true, honest to goodness paleognath birds.
Not "Aves" in the broader sense that Ken offers previously. The jaws
themselves resemble the jaws of phorusrhacid birds, even, and in this the 
confusion is easily acceptible. They never once thought that caenagnathids
and oviraptorids were related, even though various workers (including
Romer and Steel -- Linnaeans, btw) showed that the jaws were those of
classic "reptiles." It wasn't until much later, around the mid to late
1980's, that *Caenagnathus* and *Chirostenotes* were thought of as
possibly being the same taxon. Nonetheless, this was not substantially
supported until Sues, 1998, with the edentulous jaws of a caenagnath and
the postcrania of an oviraptorosaur (substantianed since Currie and
Russell, 1988, and Currie, 1990). Then the idea of *Caenagnathus* as a
bird fell off the face of Pratchett's Discworld, to fall by the eye of the
Great Turtle itself, and be lost forever.

  However, the taxonomic problem of Caenagnathiformes having priority over
Oviraptorosauria is also a tricky one. There are three solutions. One, the
Linnaean one, is to note that both were given ranks upon formation, the
first an Order [Keesey uses Ordo, as Linné did, I know why not] and the
second a Suborder. In this classification, one could easily say that
Caenagnathiformes is the Order within which Oviraptorosauria lies, but
because each is a different rank, they are separate entities.

  Two, the ICZN states that only at the Family level name and below can be
supported by rules of priority ... everything else is up to the worker.
This means that priority is not really an issue. You can use either one,
or not. This solution is an up in the air one. However you feel.

  and Three, the phylogenetic one, you could say that based on its usage
for the entire composition of its utility, Caenagnathiformes,
Caenagnathidae, and *Caenagnathus* are all synonyms of each other since
they refer to the same organism. The same problem as Opisthocomiformes for
a single genus, above Opisthocomidae. Just excessive and utterly useless
until at such time a new member which is not *Opsithocomus* is found. The
ICZN is the only thing that saved Caenagnathidae from destruction. This
leaves Caenagnathiformes as an effective junior synonym of Caenagnathidae.
This is the approach favored by Sues (1998) and other workers on the jaws
and animals.

  Then there's Ken's suggestion, which favors synonymizing
Caenagnathiformes and Oviraptorosauria; now, oddly enough, Ken's statement
makes me feel that he actually coined Caenagnathiformes independantly of
Cracraft, which appears to defy logic of both conventional naming
techniques, and conventional taxonomies. The oldest included genus,
*Oviraptor,* gets the favor for any inclusive name. *Caenagnathus*, as a
junior synonym of *Chirostenotes*, gets it for any family-level name, and
that's it. So I ask about the logic and perhaps a clarification?

  Secondly, there are three different names for the group that includes
all segnosaurs: Segnosauria (Perle & Barsbold, 1980), Segnosaurischia
(Dong, 1987), and Therizinosauria (Russell, 1997). For what reason would
it be logical to add a fourth? Also, under conventional wisdom, either the
first-named group or oldest included "genus" taxon must be the eponym, as
yours appears based on such, unless you coin a newer, non-eponymous taxon
for inclusion.

=====
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.

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