Re: kellner's ankle abstract

[David Peters <davidrpeters@earthlink.net>]

Dear Jaime and all,

It's alot easier than you're thinking.

As I've always said, just look at the feet. All archosaurs tend to diminish 
toes four and five. All crocs lose toe five. All dinos lose most of toe five. 
Pteros and protorosaurs don't until the Late Jurassic. The higher protorosaurs
(Cosesaurus, Langobardisaurus, Tanystropheus, Tanytrachelos, Sharovipteryx and 
yes, Longisquama), all have a really elongated lateral toe, just like basal 
pterosaurs.

There are more synapomorphies from head to tail, of course. I'm just picking 
out the lateral toe because it's so obvious and outstanding. Just find one 
archosaur exception to the toe rule and I'll join the 'pteros are ornithodires' 
club.
That's all you need to do.

Lagerpeton is special, no doubt, but not because it has a long toe four. That's 
what makes it ordinary.  The game is still on. Pin Lagerpeton on the family 
tree where it could belong. The clues are out there.

And enough of this "pet theory" tomato. A good scientist (and I know you are 
one), will be able to come up with some good characters that can't be refuted.

Jaime, you were good enough to look up some pterosaur photos, now dig a little 
deeper into the above named protorosaurs and give us a report.

A few more comments peppered below.




"Jaime A. Headden" wrote:

>   I will reference a few things said at the end of this email, before I
> dig into the rest. But I would like to comment on the argument suggesting
> that *Lagerpeton* has a rather "pterosaur-like" pes, given the comments
> earlier in the referenced post. 1) *Lagerpeton* is the most basal
> dinosauromorph, and in fact so far is the only non-dinosauriform
> dinosauromorph, so what other taxa have or not is irrelevant, since both
> *Marasuchus,* *Pseudolagosuchus,* and *Silesaurus* have been positioned
> right at the dinosaur/non-dinosaurian archosaurian boundary, as it were,
> if not over it, which has never been the case for *Lagerpeton.* 2) All
> species have autapomorphies, and even when pterosaurs are considered
> closer to dinosaurs than are crocs, these features of the pes remain
> stable as autapomorphies for *Lagerpeton,* while the cylindrical
> astragalus, small calcaneum, expanded distal tibia and fibula contacting
> and forming a calcaneum/astragalus concavity structure not found in crocs
> or "basal protorosaurs" (in ANYONE'S scheme, given the elongation of these
> elements with a separation of the tibia and fibula by rod-like proximal
> tarsals), imply a closer relationship with dinosaurs than with crocs, or
> other archosauromorphans.

Look beyond crocs and basal protorosaurs and ornithodires for Lagerpeton's 
ancestry. That's the surprise. It's a new sort of (probable) biped.

>
>
>   Dave Peters (davidrpeters@earthlink.net) wrote:
>
> <DP: If you assume an Archosaurian ancestry, which is not the case...>
>
>   This is a rather bold statment, given that there are competing
> hypotheses, without any sort of "settled" case. So, one should put a
> qualifier in one's statement stating in such definite terms. Like, "if,
> and only if Peters 2000 is true...." and so forth.

Just bring us one iota of evidence. It can't be that hard if the case is so 
good.

>
>
> <Once again, Kellner knew of the protorosaur paper. He refereed it.
> Puzzling why he chose to put on blinders here.>
>
>   Ask him why, don't assume a motive ("...put on blinders...").

I didn't assume a motive. I described a conscious action: "protecting the 
castle!" The same as in Unwin 2003, when he said all protorosaurs test out with 
all zeroes in his cladogram. The same as in Chatterjee and Templin 2004. The 
same as
in Feduccia 2002 (The Auk) when he holds on to the idea that Longisquama could 
be an early birdy thing.

>
>
> <Like others, apparently Kellner is clinging to what he?s been taught and
> what he teaches to others. Still, this is only one mistake. Kellner?s body
> of work has many stars. Mistakes are allowed. BTW: Anytime someone has
> reason to believe that pterosaurs are archosaurs, send me the evidence. If
> it?s valid, I?ll hand carry a six-pack of your favorite beverage to you
> anywhere in the world.>
>
>   A cladistic analysis of dinosaurs with pterosaurs had not been performed
> until nearly the 90's, so it is likely the time between then and now is
> not long enough to produce any sort of "dogmatic" rule, especially with
> the increasing intensity with which many cladistic analyses are looked at
> in. This includes Peters 2000, and because it's so "outre" with regards to
> other phylogenies, it is given a good deal of scrutiny. Notice that the
> scientific community isn't jumping up and holding each new analysis of
> hominine phylogeny as "the Holy Grail," as I think giant, bloodthirsty
> bunnies do a better job at that. Similarly, anything of such a disparate,
> critical nature is not touted as "the honest truth" until supported by
> other work. Theropod phylogeny remains somewhat in flux at certain
> critical points, but perhaps not so much as Holtz's "Rule of T" (wherein
> taxa beginning with "T" tend to be destabilizing in coelurosaur phylogeny:
> Therizinosauroidea, Tyrannosauroidea, and Troodontidae, and this remains
> the case with more or less similar results through the last half-decade),
> and basal theropods, dinosaur origins, origin and diversification of the
> Ornithischia, as well as the Sauropoda, remain contentious because of the
> lack of agreeing phylogenies.
>
>   Is it possible that the reason one might want to consider their own
> phylogeny "the truth" is because it is their own? This is what Tim was
> referring to as a "pet theory," since you want to pet it, love it, take
> care of it, like a pet, and make it do what you want. Beautiful, perfect
> things tend to be the veneer which is spread over peoples' worries, such
> as "gross" stone work, skeletal frames, cold metal and steel, in order to
> "hide" or "create" something. And like the flawed beginning of a Fabergé
> egg, eventually the end product becomes so involving and involved and
> detailed that any imperfection, however major, will be overlooked as a
> "quirk." Some elaborate on quirks, a cladistic "spandrel," by developing
> theories around unusual occurences, and *Lagerpeton* is no exception.

Easy pal, I just said there's treasure to be found. And I invited you to 
discover it for yourself.

>
>
>   Kellner's work exemplifies a similar condition: rather than look at
> basal pterosaurs, his look was at several advanced ones. The basal ones
> tend to have less detailed ankles, for the most part coming to us from the
> Solnhofen, which isn't that too detailed in bone anatomy as it is in
> soft-tissue preservation, as in most [konversat]lagerstätten, but just
> looking at *Pterodactylus* I can tell you that the large astragalus dwarfs
> the tiny calcaneum, and while disarticulated, a large cylindrical object
> is present in the tarsus of the second *Peteinosaurus,* mimicked in
> *Preondactylus,* with similar but not identical structure in
> *Rhamphorhynchus.* No object data, but my sources are the lovely photos
> from Wellnhofer's book, which are freely available, and give one an idea
> to expand research into. Not looking at basal taxa gives one an
> interesting picture, but one needs to look at basal forms when known to
> elaborate on the idea. So, Kellner's example may or may not be challenged
> by further data. There is no need to question the man, just the work, and
> the details therein (like a cladistic analysis NOT based on unverified
> tracings).

I didn't question the man. I did question the work. (I mean, where did _that_ 
comment come from??)

And the cladistic analysis was done before the days of 'unverified tracings' 
after personal examination of the specimens. Sharov, Ellenberger and Renesto 
all saw the same characters. I just raised my hand and said, "anybody happened 
to
notice -- these guys look kind of like pterosaurs!"

David Peters
St. Louis






>
>
>   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)
>
>
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