re: Pterosaur.net

[David Peters <davidpeters@att.net>]

www.pterosaur.net

First of all, congratulations on a website with great potential.

Here's a note to alert DMLers and site owners to some internal conflicts in the 
data presented at Pterosaur.net which BTW is a GOOD-looking site! Nice to see 
the traditionalists put their cards on the table. What follows is only meant to 
improve the site. I'm sure we don't want to confuse young (and old) minds by 
first saying one thing and then its opposite.

Page at a time:
http://www.pterosaur.net/index.php

1. Introduction to Pterosaurs by Dave Hone

"Pterosaur fossils are rare" is found in the same paragraph as "Even so, we 
have thousands of specimens."

"This makes them unsuitable for fossilisation" is found in the same paragraph 
as "many pterosaur fossils are from exceptionally well preserved fossil beds 
and thus are known with skin, beaks, claws, wings and other soft tissues 
preserved, and not just bones."

"Pterosaurs are not dinosaurs (or birds for that matter), but close relatives 
of them. Their exact origins are still uncertain (see the origins section)." In 
the Origins Section one reads, "Essentially, much of the information we would 
look for was lost, so there is little to tie pterosaurs to other groups through 
shared characters. This means that it is actually quite hard to see how 
pterosaurs fit in the great tree of life." then "It really boils down to two 
possibilities - the dinosauromorphs (that also produced the dinosaurs) or the 
basal archosauromorphs (that spawned many lineages)." then "There is not much 
to chose between them, and even many pterosaur experts disagree, but right now 
the weight of evidence falls (just) on the side of the dinosauromorphs." This 
all seems a bit vague, especially since the origins section includes this note, 
"We can look at their DNA, bones, muscles, physiology and much more. Since all 
organisms (if you go back far
 enough) have a shared evolutionary history, the more similar two species are, 
the more closely related they must be." 

All in all it sounds like no one has cared enough or was persistent enough, to 
find the lineage of taxa that really demonstrates an increasing number of 
pterosaur synapomorphies. Seems like anyone, even an amateur, could find a 
lineage that was closer to pterosaurs than the vague enigmas that are presented 
here. 

What is really a shame is the two studies that claimed to figure this out once 
and for all (Hone and Benton, 2007, 2008) came to their conclusions by ousting 
the other candidates, rather than testing them head to head and toe to toe. 
Yes, it was a supermatrix, but Hone & Benton chose that route when they could 
have chosen to actually look at the specimens. Too bad that study also failed 
to find a distinct lineage of proto-pterosaurs.

"To do this they had a large wing membrane stretched from an elongate finger on 
their hand that connected to their body." This conflicts with the John Conway 
illustration at http://www.pterosaur.net/anatomy.php in which the wings 
attached at the leading edge of the thighs.

"Some also had a long tail with a small âtail vaneâ flap on the end which may 
have also helped with steering (see the flight section)." There are no 
descriptions of the tail or vane in the flight section. Tail vanes on living 
flyers are purely decorative.

"The additional membranes (especially the front one) controlled by a special 
bone called the pteroid would have helped with steering." The pteroid was 
inboard and would not have been such a great steering aid.

"On the ground the ârhamphorhynchoidsâ were probably pretty poor. Their large 
rear membrane would have shackled their hindlegs together making walking 
difficult, and the shape of their hips and upper legs meant that could only 
really sprawl and not walk upright." Wait a minute! This doesn't make sense. 
The plesiomorphic condition is "unshackled," no matter which ancestry one 
chooses. Perhaps there was a misidentificat
in the uropatagia(um)? Maybe it was more like the unshackled Sharovipteryx?

"Eggs were probably laid a few at a time and buried in nests..." If buried in 
nests, were these made of mud, sand or leaves and sticks? If they were buried, 
how did the eggs end up being covered in volcanic ash (Wang et al. 2004) or 
flood sediments (Ji et al. 2004, Chiappe et al. 2004)? Why didn't they just 
stay buried where momma put them? And if buried, why did they have eggshells 
thinner than any known archosaur? -- As thin as lizards that retain their eggs 
until just before partuition?

Since this site seems to be devoted to clearing up myths and misunderstandings, 
it sure would be great to see some EVIDENCE put forth for a single uropatagium, 
deep chord wing membrane, a buried nest, etc.  A website like this, owned and 
operated, is capable of doing anything, from propaganda to real substance.  

Again, this is just a note of encouragement with a few editor's notes as alerts 
to potential confusion.

Cheers, and more later.


David Peters
davidpeters@att.net

cc: MW, DH, pterosaur.net@googlemail.com