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Re: Coeluridae as a Wastebasket for Coelurosaurs



Jaime,
I don't recall Tom Holtz ever suggesting Coelurus is a maniraptoran (at least recently), and even placing it in Maniraptoriformes is rather iffy. He did indeed place Compsognathids in Maniraptora for a while last year, but now he has them completely outside of Maniraptoriformes.
And if you apply his cladistic definition of Maniraptoriformes, it would include Tyrannosaurs in Sereno's cladogram. There does seem to be some consensus on the more inclusive taxon Coelurosauria, but certainly *NOT* on the contents of Maniraptoriformes (not only is Sereno's different, but Holtz himself has compsognathids hopping in and out of it in very different positions just within the last year). My {{Ornithomimidae to AVES}} does indeed appear to be a synonym of Maniraptoriformes Holtz (1995-96), but certainly NOT a synonym of Maniraptoriformes Sereno, 1999 (which included tyrannosaurs) or of Holtz, 2000 (which included compsognathids). I repeat, there is no consensus (especially looking at cladograms of 1999-2001).
As for wastebaskets, Mike Keesey splits his up into a series of separate "incertae sedis" wastebaskets, while I prefer to combine several of them into one larger organized paraphyletic "wastebasket" (Coeluridae). I still think there is more than one way to skin a cat, and Mike's is just different (not necessarily better). Since I don't recognize as many formal taxa, I have fewer wastebaskets, but I clearly mark them as paraphyletic. On the other hand, Lophotrochozoa is such a wastebasket that I won't recognize it even informally, and yet it is being passed off as a holophyletic clade and uncritically accepted as such by most biologists (which I think is far more damaging than any well-organized paraphyletic assemblage such as Coeleuridae).
And we seem to agree that Orders Ornithischiformes and Saurischiformes are acceptable taxa (you accept them as clades and I do also with some reservations), and I code them as sister groups (informally recognizing a dinosauria clade), so where's the problem? Keeping them as two separate orders gives me more flexibility just in case Saurischiformes is paraphyletic rather than holophyletic.
And finally, I am not at all impressed by "laundry lists" of synapomorphies. Remember that Sereno had quite a nice list of synapomorphies for Ornithodira, and yet the idea of this as an exclusive clade for pterosaurs, dinosauromorphs, and Scleromochlus, is being rapidly abandoned as Dave Peters viewpoint is being overwhelmingly accepted. This is definitely one of the major reasons I oppose cladistically finely split, intermediate taxa like Ornithodira. As an index to the literature, it is worse than worthless, it is confusing and harmful (a point made many times by Mayr, Ashlock, and others). For more on that I would suggest reading again Michael Benton's article in Biological Reviews last November, which has been selectively criticized while ignoring the more important valid points that it makes.
Past my bedtime & a little cranky,
Ken
********************************************************
From: "Jaime A. Headden" <qilongia@yahoo.com>
To: dinosaur@usc.edu
CC: kinman@hotmail.com
Subject: Coeluridae as a Wastebasket for Coelurosaurs
Date: Tue, 29 May 2001 18:53:07 -0700 (PDT)

Ken Kinman (kinman@hotmail.com) wrote:

<Now responding to David, "wastebasket" is a subjective term,
and I only use it for groups I am convinced are polyphyletic (or
so paraphyletic as to be counterproductive----such as
Lophotrochozoa or Condylarthra).>

  What we think we know is that these last two taxa are
paraphyletic, or somewhat polyphyletic... Condylarthra
especially may comprise essentially the basal members of many
subungulate and ungulate groups. But *Coelurus*, however, has
been suggested in recent and ongoing analyses, especially by Tom
Holtz, to be a maniraptoran, so using the group Coeluridae to
represent a wastebasket (instead of not using a name at all) for
coelurosaurs generally is not a good idea. Maniraptoriformes is
well established, unless the lack of use here is the presence of
an -iformes suffix....

<Mike Keesey and I organize our wastebaskets differently.>

  Mikey Keesey tried to avoid wastebaskets. We doesn't organize
them at all, but places them on the stem under the clearest node
he can find, or is suggested.

<The {{Ornithomimidae to AVES}} clade seems to be cladistically
equivalent to Maniraptoriformes Holtz (1996?).>

  1995a,b, and it _is_ the (*Ornithomimus* + Neornithes) node,
by definition.

<I don't feel compelled to name it, but since it has been named,
I put in this synonymy. Since the contents of
"Maniraptoriformes" depends on whose cladogram you are using,>

  How so? As a synonym for Coelurosauria? The only coelurosaurs
that don't seem to fall into Maniraptoriformes are various taxa,
*Compsognathus* et al., *Dryptosaurus*, *Ornitholestes*,
*Nedcolbertia*, *Scipionyx*, and probably even Tyrannosauroidea
(!), that are put here based on morphology. Indeterminate [but
most likely being] maniraptorans like Troodontidae and even
possibly *Bagaraatan* can be applied specifically, based on
comparison. Maniraptoriformes, by analyses stretching back to
Gauthier's 1984 PhD dissertation and it's 1986 publication,
includes *Ornithomimus*, *Oviraptor*, *Troodon*, *Velociraptor*,
*Archaeopteryx*, and "true" "birds."

  Holtz, 1999, finds the following phylogeny to be the strict
concensus of most analyses as published:

  (*Compsognathus* (*Ornithomimus* (*Oviraptor* (*Velociraptor*
(*Archaeopteryx* + Birds)))) ... troodontids, tyrannosaurids,
and therizinosaurids, among others, tend to move about. Sereno
and Holtz both tend to find *Ornithlestes* between
*Compsognathus* and *Ornithomimus*, so this appears to be the
concensus arrangement. Making a wastebasket that doesn't exist,
in my opinion, doesn't help.


<I could formally split Saurischiformes into two separate orders, but a theropod order could be paraphyletic to a sauropodomorph order, which would make theropods doubly paraphyletic (to Aves and sauropodomorphs) or even triply paraphyletic if Ornithischiformes is a theropod exgroup.>

  Based on nearly all analyses, though Paul and Olshevsky find
herbivorous dinosaurs together, Theropods and Sauropodomorphs
are mutally exclusive, and are defined and considered as such,
within Saurischia -- it is perhaps foolish to not retain the
establishment on the basis that they may be paraphyletic, or
doubly paraphyletic. Ornithischia is exclusive of both, 1) by
most analyses (Sereno, 1986, 1999; Benton et al., 1999; Novas,
1991, 1994, 1995, 1997....; Sereno and Novas, 1993; Sereno et
al., 1993 [Eoraptor]) that consider their relationships, and 2)
in the broadest sense, as no theropod can be an ornithischian,
or vice versa, and in the same context, neither can any
sauropodomorphan.

<I code the two dinosaur orders as sister groups, but such a
united clade doesn't have any unequivocal synapomorphies>

  Oh, I disagree. So does Novas, 1991, and Sereno and Novas,
1993, and Novas, 1993, and Novas and Sereno, 1993, who found
upwards of five unambiguous synapomorphies of a birds +
*Herrerasaurus* group that excluded both sauropodomorphans, and
ornithischians; Sereno, 1994, found a lot more that contains
*Lesothosaurus*, Thyreophora, Marginocephalia, and Ornithopoda,
as Ornithischia, excluding theropods and sauropodomorphans; and
both Upchurch, 1998 and Wilson and Sereno, 1999, find more than
five or so synapomorphies of the *Vulcanodon* and other sauropod
clades, and a *Plateosaurus* + *Saltasaurus* clade, which define
Sauropoda and Sauropodomorpha. These analyses show [1] that
Dinosauria is monophyletic, and [2] it includes two mutually
exclusive groups, Ornithischia and Saurischia, the latter which
[3] contains two mutually exclusive groups, Theropoda and
Sauropodomorpha, which cannot be further moved around without
collapsing internal nodes beyond recognizability.

<and also has a shorter history of usage as a formal taxon (I
may formally combine them into one order eventually, but not
yet).>

  Owen named Dinosauria in the mid 1800's, just a few decades
later were the direct subgroups defined. It was also considered
after that, more recently, that everything was indeed
polyphyletic and it was wiser to retain them as just subgroups
of a clade Thecodontia, because no one could find synapomorphies
beyond predatory or herbivorous specializations. Until 1991,
that is, and Sereno's and Novas' PhD works, and Gauthier's 1984
PhD work.

<...a single paraphyletic taxon like Coeluridae (with one or
more exgroups) when there is almost no consensus as to how they
are all interrelated.>

  Sereno et al., 1994, 1996, 1998; Holtz, 1995a,b, 1996, 1999;
Padian, Hutchinson, and Holtz, 1999; Sereno, 1999 ... these all
contrdict the previous statement, and especially where Padian,
Hutchinson and Holtz (1999) and Holtz (1999) who detailed the
true consensus.

=====
Jaime A. Headden

  Aaaaaaaaaaaaaaaaaaaahhhhhhhhhhhhhhhhhhr-gen-ti-na
  Where the Wind Comes Sweeping Down the Pampas!!!!

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