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Sobral and Langer 2008 (was pteros have lift-off)

David Peters wrote:

> And you might want to reread the Langer and student
> abstract in the 2008 JVP abstracts. That will bring the
> total to 2.

Not having seen or read the Langer and student abstract in question, could you
(or someone else) elaborate? Or at least cite these "2".

It's not online yet, but here is the ref and a truncated quote from it:

Sobral, G. and Langer, M. 2008 JVP 28: supplement to (3): 145A
A supertree approach to prolacertiform phylogeny

"based on 28 published phylogenies...the majority consensus tree shows a paraphyletic Prolacertiformes with two major clades: ...(1) drepanosaurids, Longisquama, Sharovipteryx, and Pterosauria; (2) the other group has Protorosaurus basal to another dichotomy including the Prolacerta-archosaur clade, and a group composed of tanystropheids plus forms such as Boreopricea, Pamelaria, and Malerisaurus."

I quibble with the second tree, but the key here is the connection with some fenestrasaurs (sensu Peters 2000b) and pterosaurs has been confirmed by this study.

Hone and Benton 2006 tested Peters 2000b and found similar topologies (!) -- but urged caution and wished to stay with conventional trees aligning pteros with dinos -- despite agreeing with Bennett 1996 when they stated, "Pterosaurs have been allied to virtually every basal and crown-group archosaur clade as well as to the dinosaurs, but few characters can be found that unite them with any other clade among the archosaurs." That admission is powerful evidence and is probably the source for their next statement...

Hone and Benton 2006 also wrote: "The Pterosauria has been a notoriously difficult clade to place in the diapsid tree: pterosaurs appear suddenly in the fossil record and in full possession of all their highly derived characters."

No taxon appears suddenly in the fossil record! There are always clues to ancestry.

You just have to include the candidates, do the work and PAUP will reveal what you seek. Unfortunately Hone and Benton 2006 made their conclusions without supporting them with the supertree they mentioned in their conclusion, nor even one sentence within the body of the text. Evidently these were oversights that will hopefully be corrected within the upcoming Zitteliania volume. We'll see. Not holding my breath though, because n 2006 they indicated a very broad range of taxa they preferred, stating, " The Pterosauria are not closely related to the Prolacertiformes and should instead remain among the Archosauria and probably among the derived archosaurs." That's a very bad sign when the 'preferred' cladogram can't nail down a sister taxon.

The word 'should' you'll recognize as a "weasel word." By that I mean, it's a prediction leaving some room for retraction, not a statement of fact supported by evidence. The word 'probably' falls into the same category. If these guys were playing poker, I'd say they were bluffing by including such weasel words.

I can state without fear of retraction and with lots of evidence (see prior "pteros have lift-off for a preview) that Cosesaurus, Sharovipteryx and Longisquama were sister taxa to the Pterosauria. But let's forget about those taxa for a second: we can go back to Langobardisaurus, Tanytrachelos and Tanystropheus, all of which share that attenuated tail, hyper-elongated fifth toe and lots of other characters. But let's forget about those taxa for a second: we can go back to Macrocnemus, Jesairosaurus and drepanosaurs, which Senter and others seem to like. I would take you back further, but then you'd have to see the MacClade file.

(I know of two Tecovas taxa (Late Triassic, Texas) that have been earmarked as
potential proto-pterosaurs. But these have yet to be formally described.)

Yes! Tim, good work!
If you're referring to Pteromimus, it is indeed related to pterosaurs. It's a langobardisaur The first one recorded for North America, but cladistically its pre-Cosesaurus but it shows they too had an antorbital fenestra. Very important.

If Procoelosaurus is also on your Tecovas list, it's a basal croc. Both interesting specimens.

Tom Holtz wrote:

> _Guanlong_, a basal tyrannosauroid, is older than _Archaeopteryx_.

Thanks - I'd forgotten about that one. I guess _Guanlong_ would be the oldest
coelurosaur that has forelimbs preserved. Forelimb length is about 60% of the
hindlimb length.

Yes, you're right, but let's take it up a notch. Forelimb length is about 100% of the hindlimb length in Archaeopteryx. i'm still wondering, what is the explanation for such an extension on this taxon -- or any pre-Archaeopteryx taxon -- with such elongated forelimbs, non-supinating/pronating antebrachia and trenchant manual unguals if not for arboreality?



David Peters