a closer look at Lu and Ji 2006

[David Peters <davidrpeters@earthlink.net>]

And yes, please forgive the typo of Li vs. Li (Ji). Thank you Dr. Unwin.

Let's start with the basal taxon: Anurognathidae. It would be better  
to start with some Triassic taxon, I would think. So there's the  
first red flag.

Strangely the anurognathidae are not a sister taxon (to the exclusion  
of all other pteros) to Dimorphodon + Preondactylus (which form a  
clade of their own when properly reconstructed (and a tip of the hat  
to Dr. Unwin again who predicted this many years ago)). Here both are  
successively basal to Sordes, a mistake I also put into print many  
years ago. It's easy enough to do given too few taxa and characters.  
Strangely that forces Eudimorphodon three steps higher in the  
cladogram, higher than Scaphognathus and Dorygnathus. That's another  
red flag.

The inclusion of Peteinosaurus(?) Ex3359 and MCSNB 8950 would help  
this portion of the cladogram.

When MPUM 6009 and Austriadactylus are included, they attract  
Eudimorpodon ranzii and the other Eudimorphodons abit lower on the  
cladogram, keeping the Triassic forms at the base, morphologically  
and chronologically where they belong. In this way, the various Mid  
Jurassic Campylognathoides,  which are strongly attracted to  
Eudimorphodon, forms a separate branch which, in time, begets the  
various late Jurassic Rhamphorhynchus species, but not without a size  
squeeze during the transition. All forms blending and in  
chronological order.

When six Dorygnathus are used in a cladogram, instead of one as in  
prior works, you find that the short-toothed Donau specimen is basal  
to the more derived wicked-toothed forms, and that Sordes is its  
sister (more about Sordes and Co. later). The Dorygnathus more  
precisely known as SMNS 50164 has a tiny pterosaur as its sister  
taxon, TM 10341. When this pterosaur is included (which it is not in  
Lu and Ji 2006) not-so-tiny Beipiaopterus is strongly attracted to it  
as are a number of other tiny pterosaurs, including SOS 2428, AMNH  
1715 and Wellnhofer's No. 42.  The last two tiny pteros are sister  
taxa to SOS 2179 and Huanhepterus on one branch. On another sister  
branch are a series of increasingly larger forms beginning with  
Jidapterus and Chaoyangopterus and leading to Zhejiangopterus and  
Quetzalcoatlus (but not Azhdarcho and Co. more about them later). So,  
some pterodactyloid-grade pterosaurs show up on this branch, but the  
rest do not.

The Dorygnathus known more specifically by their numbers as SMNS  
55886 and R 156 are basal to a branch that includes in order: D.  
purdoni (another tip of the hat to Dr. Unwin for that) and  
Angustinaripterus, long touted as a good transitional form between  
'rhamphorhynchoids' and 'pterodactyloids' but strangely missing from  
this analysis, and as I look back -- all other recent analyses. What  
happened to our star quarterback? Put him back into the game and see  
what happens!

Anyway, the wonderful Angustinaripterus with the garage door teeth  
does lead, not surprisingly, to others with similar teeth and  
everything else, Gnathosaurus and Ctenochasma + Pterodaustro, but not  
without yet another phylogenetic size squeeze. And with that we have  
our second branch of 'pterodactyloid' - grade pteros without  
including all of them. Strangely, Lu and Ji place the horizontal- 
toothed pteros with sharp-snouted Germanodactylus, which seems as  
unlikely as pairing a spoonbill with a woodpecker. There are better  
matches out there. They just need to be included.

Back to Sordes.

Pterorhynchus is strongly attracted to Sordes, but so far has left no  
sister taxa. Where is Pterorhynchus in these latest studies? Nowhere.

Scaphognathus is also strongly attracted to Sordes and is basal to  
all remaining pterosaurs. If one includes all three (?) well-known  
Scaphognathus specimens (which Lu and Ji do not), one finds that S.  
crassirostris and SMNS 59395 are basal among them. The third named  
specimen, the Maxberg specimen, continues a size squeeze that  
continues even further with an even tinier pterosaur, TM 13104 and  
further up the line, G-mu 10157, both with slightly elongated  
metacarpals. Afterwhich one gets a big size jump with cycnorhamphids  
and ornithochierids (they have the same strange feet among other  
characters) emerging from the genetic pool. And so a third branch of  
'pterodactyloid'- grade pterosaurs emerges with a morphological  
spectral blend from a 'rhamphorhynchoid' base. Again, remember, this  
doesn't happen in a cladogram with tiny pterosaur exclusion. In other  
cladograms you get confusion and 34,000+ MPTs.

There is another pterosaur that is so strongly attracted to  
Scaphognathus that, if not for its diminutive size and neotenous tail  
(already on the wane in other Scaphognathus anyway) and its slightly  
elongated metacarpus, it might have been named Scaphognathus sp.  
That's the tiny pterosaur Wellnhofer named No. 9. Despite having a  
short scaphognathine rostrum, it also has a slightly sharper rostrum.  
And here begins the fourth and final branch of 'pterodactyloid' - 
grade pterosaurs derived from rhamph-type ancestors.

Strongly attracted to No. 9 is AMNH 1942, which has the same size  
torso, wings and legs, but a longer neck and rostrum. AMNH 1942 is  
also known as Pterodactylus and it is basal to the other  
Pterodactylus forms we all know and love, including the big one,  
Diopecephalus. Lu and Ji place two Pterodactylus between  
Beipiaopterus and Eosipterus. In this case, the addition of No. 9,  
AMNH 1942 and other pteros would provide the realignment.

Another sister to No. 9 is No. 12 which has a longer and noticeably  
sharper rostrum. It begets all of the sharp-nosed pteros, starting  
with various versions of Germanodactylus (including Eosipterus). Lu  
and Ji show Eosipterus to be a sister taxon to Germanodactylus (which  
is good) and also to the ctenochasmatids + cycnorhamphids (which is  
bad = doesn't make sense). See above for better matchups.

It is difficult for me to understand how Germanodactylus can be so  
far removed from (azhdarchids (not including Q. and Co.)) +  
(nyctosaurs + pterandons)) + (tapejarids + dsungaripterids), but  
that's how Lu and Ji show it.

As mentioned earlier, the addition of more tiny pteros and more  
pteros in general pulls Quetzalcoatlus, Zhejiangopterus, Jidapterus  
and Chaoyangopterus away from Eopteranodon + Eoazhdarcho + Azhdarcho,  
which form a separate clade with a convergent elongated cervical  
series. The flat versus pointed shapes of the dentaries are  
diagnostic, as are a whole raft of other post-cranial characters.

Lu and Ji's family tree of tapejarids and dsungaripterids has  
problems (but that's because Quetzalcoatlus and Zhejiangopterus are  
incorrectly basal here). The dsungaripterids should branch off first  
(if germanodactylids are basal, as they should be), followed by the  
monophyletic tapejarids.

It just takes more taxa and more characters and all the confusion  
melts away.

David Peters
St. Louis