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Re: Unwin's cladogram - long



> 9. Rostrum low with straight or concave dorsal outline.
>
> Good character for all non-dimorphodontids -- except that Cosesaurus and
> Longisquama also display the apomorphic condition. It goes to show that
> the convex rostrum is derived.

The reversal from the convex state would still be an apomorphy of
Caelidracones. Just like no longer opposable 1st toes are a good human
apomorphy.

> 11. External narial opening low and elongate.
>
> Good character for nearly all non-dimorphodontids, except that
> Cosesaurus and Longisquama also display the apomorphic condition. It
> goes to show that the big naris is derived.

See above.

> 14. Orbit larger than antorbital fenestra.
>
> Again, Cosesaurus and Longisquama display the apomorphic condition. So
> do Tanystropheus and Megalancosaurus. Dimorphodontids are different
> because they are derived. After all you have to develop an AOF _after_
> you have an orbit, right? So the AOF has to start small.

First the AOF appears, then it grows beyond orbit size, and then the orbit
grows. This seems to be the interpretation here.

> 20. Metacarpals I, II and III of equivalent length.
>
> I noted a similar character, but unfortunately it doesn't start to kick
> in until after Scaphognathus crassirostris, when I<II=III. This occurs
> three times by convergence. I=II=III occurs five times, and once in the
> outgroup, the Anurognathidae, which isn't supposed to happen according
> to Unwin, who scored a zero for this matrix box.

Is Anurognathidae one OTU, and does the change happen inside that group? If
so, 0 is the proper coding, because it's the inferred state in the ancestral
anurognathid.

> In this character section Unwin muses on the possibility "that
> Pterodactyloidea might share a closer relationship with Anurognathidae
> than with any other 'rhamphorhynchoid' clade" ? noting pelvic shape
> similarities, reduction of cervical ribs and reduction of caudal series.
> David, if your analysis can't get you any closer to the answer than
> this, it's time to dig deeper. Seriously.

The problem is just that this could have to be taken literally. The "digging
deeper" part, I mean. If despite a huge number of characters an analysis
doesn't produce a well-resolved tree, then the solution is to add more
taxa -- and if all taxa are already included, then it's time to dig for more
fossils.

> Wait to publish until you're sure!

Until he is subjectively sure? That's not the purpose of a cladistic
_analysis_, which is supposed to show what _the data_ say.

> Rhamphorhynchidae ? Sordes > Rhamphorhynchus muensteri
>
> 22. Less than 11 pairs of teeth in the rostrum.
>
> Unwin includes Angustinaripterus in this clade, and it has more than 11
> pairs of rostral teeth. Same with Rhamphorhynchus intermedius.
> Otherwise, this clade is internally consistent.

Two reversals, so what? Or are those two the basalmost rhamphorhynchids?

> 27. Caudal vertebral series shorter than dorsal series.
>
> One of the outgrowths of the unossified juvenile theory is that some
> parts never ossify as adults in certain taxa (i.e. Nyctosaurus fingers).
> The caudal series in pterodactyloid-grade pteros is another example.
> Often longer than the ossification will show, still not always longer
> than the torso.

The problem is just... unossified bones are cartilage or tendon. The latter
is probably never, the former never at all preserved in fossils, even when
keratin is still present. (Except _perhaps_ in some mummies, but I don't
know that, and I doubt it.) Unossified finger bones would be cartilage, and
that stuff rots very fast. It simply doesn't fossilize, not even as a
colored stain. Now do you think you've found skin impressions of the
fingers?

> 29. Wing metacarpal (IV) at least 80% the length of the humerus.
>
> Good character. No exceptions.

Wouldn't matter anyway. :-)

> 30. Pes digit V with a single phalanx or entirely absent.
>
> Actually the ungual (sometimes soft) is retained by basal pterosaurs. A
> rather large two phalanx pedal digit V is retained by Azhdarchids

See above.

> (and shows up in their footprints!),

Really? Is there a photo somewhere? :-9

> neural spines grow together without fusion

Approach each other? Or what? ~:-|

> 34. Pneumatopore piercing the anconal surface of the proximal part of
> the humerus.
>
> I avoid characters like this, which can only be viewed on a few taxa.

There are several very good papers on missing data -- and how it doesn't
matter if there aren't _huge_ lots of it -- in the JVP of June.

> 37. Reduction of proximal ends of metacarpals [all or some do not reach
> the carpus]
>
> Here is a great example of selective ossification in that the
> metacarpals only ossify distally, but most certainly maintained some
> sort of softer tissue contact with the carpus.

Fine, then let that be the character. :-) (And why do you write "most
certainly"?)

> Euornithocheira ? Ornithocheirus mesembrinus > Pteranodon [same as above
> clade, sans Istiodactylus]
>
> 39. Concave posterior margin of nasoantorbital fenestra
>
> Also occurs in the outgroup: Scaphognathus, Pterorhynchus,
> Cycnorhamphus, Diopecephalus, Thalassodromeus.

Is any of these the sistergroup or 2nd outgroup of Euornithocheira?

> Absent in the ingroup:
> Haopterus, Coloborhynchus spielbergi, Criorhynchus, and possibly the
> Field Museum Nyctosaurus.

Is any of those the basalmost member of Euornithocheira?

> Unwin also notes the character "radius less than half the diameter of
> the ulna" which joins Istiodactylus to this clade, but is not found in
> Pteranodon and Nyctosaurus. Now that's a good character!

Two reversals somewhere high up don't matter.

> Pteranodontia ? Nyctosaurus > Pteranodon [finally a clade I can believe
> in!]

"To believe means to know nothing"
-- proverb

> 43. Dentition absent
>
> Actually the anterior premaxillary and dentary teeth form anterior jaw
> tip spikes in this clade,

Are you sure you haven't just found the shadow of the beak tips on some
photos?

> 45. Pneumatic opening in palmar surface of proximal part of humerus.
>
> As before, I avoid such minor and restrictive characters.

Why "minor and restrictive"?

> 48. Extensive sagittal cranial crest
>
> Unwin admits that this character is absent in some six ingroup taxa, has
> a different morphology in select taxa, then guesses that immaturity or
> gender might explain the differences. Then scores for the plesiomorphic
> condition (with the proviso that this may be inappropriate). No. You
> can't do this when you build a matrix. Score the character as is and let
> PAUP tell you what the relationships are later.

But... if those _are_ ontogenetic or sexually dimorphic features, then your
proposal would amount to "garbage in, garbage out". I can't say what I'd do
if I actually knew something about pterosaurs, but if I had to do it right
now, I'd probably just ignore the character, instead of running the risk of
parthenogenetic clades.

> Unwin also notes that
> relationships within this clade are difficult to resolve. Heck yeah!
> This is a mixed bag, Dave!

In that case it should (ideally) be a polytomy of several well-resolved
clades.

> Unwinnotes that in putative juveniles the plesiomorphic
> state is present. That's because they're not juveniles.

Why? It's expected that juveniles look more plesiomorphic than adults.

> Unwin also notes a strong anterior bowing of the wing phalanx 1. Not
> sure if this means anterior convex or concave. But in all
> Germanodactylus available to me (about 5 specimens) this phalanx is
> straight.

And the photos were taken in which angles...? :-)

> Neoazhdarchia ? Tupuxuara > Quetzalcoatlus
>
> Not numbered, only under remarks: Apomorphies include: notarium, loss of
> metacarpal contact with distal syncarpal, rostrum forms 88+% of the
> total skull length. All of these characters are also shared with some
> Pteranodons and Nyctosaurus. The latter character is also shared with
> Pterodaustro and Liaoningopterus.

All of which are far away in the cladogram, right?

> In conclusion ~
>
> With so many internal problems, many recognized by the author, this
> report appears to be fatally flawed and essentially useless.

Sounds like a vast exaggeration to me. I mean, even Sereno finds lots of
universally accepted clades. :-)

> Even so, this analysis has taught me that the next time a cladistic
> analysis is proposed, more taxa and more characters have to
> be employed. No supra-generic taxa. Only specimens.

Yep.

> And strict reliance on the data
> without guesstimates regarding maturity and gender differences.

Maturity is not always such a guess. It's often a certainty, when things
like bone texture are known.