[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: they keep on growing despite early fusion
> re: squamates. Anybody can discover what I did, just by plugging
> in taxa.
David Marjanovic wrote:
That sounds simple, but you're talking about a PhD thesis in terms of amount of
work. The fact that you expended far less effort than a thesis does not bode
well for the quality of your work.
>>>> Wait a minute. You guys love cladograms! If you don't have one already
>>>> prepared, then you can start with just Iguana, Eudimorphodon,
>>>> Preondactylus, Marasuchus and Euparkeria. That's not a big deal. Or use an
>>>> established data matrix and plug in the excluded taxa. And why insult a
>>>> work you are unfamiliar with? Ten times more taxa than any prior study,
>>>> and growing every day, is not "far less effort". And who says it takes
>>>> alot of effort? Either you don't like your boat rocked, or you are happy
>>>> with keeping your various enigma taxa as enigmas. That's fine by me, but
>>>> quit beefing and come up with a genus that's demonstrably closer to
>>>> pterosaurs! <<<<<
> In fact, Benton 1985 nested pterosaurs next to lepidosaurs and far
> from archosaurs in the only published cladogram that had all three
> taxa included.
Do you mean this paper?
Classification and phylogeny of the diapsid reptiles, Zool. J. Linn. Soc. 84:
97 -- 164 (1985)
Because this one has Pterosauria as the sister-group to the rest of
Archosauromorpha (fig. 17 and p. 154).
>>>> But also next to Lepidosaurs and far from Euparkeria + all other
>>>> archosaurs. Check the entirety of the literature. For all its faults, this
>>>> is the one and only time Lepidosaurs have NOT been excluded from
>>>> consideration. Benton 1985 was a breakthrough and a one-time-shot. Also,
>>>> perhaps, an unfounded embarrassment, because Benton dropped Lepidosaurs
>>>> from all subsequent lists. <<<<
Also note that it does not present a cladistic analysis. I don't know if the
computing power for a matrix with that many taxa was even available in 1985.
Instead, Benton presented subtrees (called "cladograms") and supplied a list of
apomorphies for each node, without trying to find out if his subtrees together
were in fact the most parsimonious tree that explains the data. There is no
data matrix, just those lists!
>>>> However done, this is one of the first papers of the cladistic era.<<<<
At the time, it was the most thorough treatment of the question that had ever
been made. For today's standards, it's _not even publishable_ in the form it
was published. (Even though the data -- the mentions of which character states
are present in which taxa -- must not be ignored in modern studies.)
>>>>True. I also have beefs with those who put today's standards on yesterday's
>>>>papers -- without demonstrating more parsimonious solutions.<<<<
Here's the section of the text on Pterosauria (pp. 134 and 136) [NO LONGER] in
Pterosaurs possess an antorbital fenestra, but Wild (1978: 247) considered that
this may be a convergence.
[True. Also in Varanodon, Chroniosaurus and Proterochampsids + Parasuchians
which have a separate origin from Proterosuchians, or so you'll see when you
test them.] So it does happen. Often enough.]
Further, Wild (1978: 246Ã253) reviewed numerous similarities between the early
pterosaurs and various 'eosuchians' and differences from early thecodontians.
[Sounds phenetic to me.]
[Not to me. Completely different lineage--NOT both derived from Youngina, but
Wild did not know that back then.]
The characters shared with *Youngina*, *Prolacerta* and others are all
primitive to diapsids as a whole, except for the reduced quadratojugal, the
ossified sternum, the 'hooked' 5th metatarsal [which is now considered an
autapomorphy of the diapsid crown-group, now that the younginiforms have been
thrown out of that clade], and the 3-pointed teeth seen in *Eudimorphodon*.
>>>>> This is a case of looking for your wallet under the streetlight when you
>>>>> know you lost it in the alley, because the light is better. A priori
>>>>> [always a sin] and pre-cladistically, Wild was looking for something
>>>>> lizardy with a long finger four. You don't find that among small
>>>>> archosaurs. If you do, let me know. This is the BIG sticking point. Wild
>>>>> was familiar with the little version of Tanystropheus. Had the right
>>>>> teeth, toes, slender tail, etc. but perhaps, with that neck, too far off
>>>>> the imagined ancestor. Also, back then a pterosaur sternum was a sternum
>>>>> lacking clavicles. Now we know, thanks to Wild 1993, a pterosaur sternal
>>>>> complex includes clavicles and interclavicle.<<<<<
Pterosaurs display all of the characters of the Neodiapsida as far as can
be determined, except B2 (ventral processes on parietals) and B6 (emarginated
quadrate). [B is the list of autapomorphies of Neodiapsida.] They show some
archosauromorph synapomorphies (C4--10), but lack others: C1--3, 11--14.
Pterosaurs share two characters with the Lepidosauromorpha [including
Younginiformes]: the single ossified sternum, and specialized sternal
attachments for the ribs. The most parsimonious position for the pterosaurs at
present [based only on the mentioned characters!] is within the
Archosauromorpha, as sister-group of all other archosauromorphs. Further work
is needed on this question as well as on the [surprisingly ignorant] suggestion
that Pterosauria are the sister-group of Aves (Gardiner, 1982)."
>>>> Understood. And I understand Benton's world view that both
>>>> archosauromorphs (rhynchosaurs, Trilophosaurus, Prolacerta and
>>>> Archosauriformes (Proterosuchus to Dinosaurs) and lepidosauriformes are
>>>> both derived from Youngina and kin. If you test that you'll find it no
>>>> longer true. I know, it's a struggle to find sister taxa to the
>>>> Pterosauria without Longisquama, Sharovipteryx, Cosesaurus and
>>>> Langobardisaurus in the mix. I can see why earlier workers, desperate for
>>>> a solution, plugged pterosaurs into archosauria or archosauromorpha [but
>>>> notice no single genus is EVER closely associated! Even by Hone & Benton
>>>> who had the last word.]. But you and I both know this was by default.
>>>> Nothing in the archosauromorpha looks like or even smells like a
>>>> pterosaur, and that [paraphrased] according to Bennett 1996 quoted in Hone
>>>> & Benton 2007.] <<<<<
so I conclude the paper I quote above is what you mean and misremember. It is,
after all, the closest the pterosaurs have ever come to the lepidosaurs -- and
to the younginiforms! -- in a published paper.
>>>> Good, then I've made my point: Exclusion is bad. Try to plug in a
>>>> lepidosaur. Take another look at Huehuecuetzpalli (free pdf if you Google
>>>> 'basal lizard Reynoso') Happy hunting, David. I am always at your service.
>>>> DP <<<<